Depa men o Chemical Enginee ing
S udy on adso p ion beha io o a e ea h elemen s on o magne ic
nanocomposi es o ca boxyme hyl chi osan, algina e and no el
biodeg adable polyamide
by
Hamed eza Ja adian
in ul ilmen o he awa d o he deg ee o
DOCTOR
by
Uni e si a Poli ècnica de Ca alunya
Supe ised by:
D . Ana Ma ia Sas e Requena
D . Mon se a Ruiz Planas
Ba celona, 2020
Thesis p esen ed by compendium o publica ions
ACKNOWLEDGEMENT
I would like o exp ess my since e g a i ude and hea el hanks o my supe iso P o .
Ana Ma ia Sas e Requena o gi ing me he oppo uni y o do he esea ch wo k in
Depa men o Chemical Enginee ing, Uni e si a Poli ècnica de Ca alunya, and he since e
guidance and e o s owa ds he success ul comple ion o he esea ch wo k, apa om being a
g ea sou ce o suppo and mo i a ion o me.
My hea el hanks go o P o . Mon se a Ruiz o he cons an help and p o iding
necessa y labo a o y acili ies o pe o m he esea ch wo k. P o ound hanks o he kind hea
and g ea cons an suppo o sol e my p i a e p oblems ou side he esea ch wo k.
I exp ess my since e hanks o P o . Mehdi Tagha i, Depa men o Chemis y, Facul y
o Science, Shahid Cham an Uni e si y o Ah az, 61357-43337, I an, o his in e es o
con ibu e in he esea ch wo k by his con inuous suppo and aluable sugges ions.
Las bu no he leas ; I would like o dedica e my hesis o my belo ed pa en s o hei
cons an inspi a ion and encou agemen no only du ing he esea ch wo k bu also a all he
momen s o my li e.
The hesis is de eloped in he ame o he p ojec en i led “Sepa acion/ ecupe acion de
ie as a as median e p ocesos de so cion en biopolime os, composi es y memb anas.
(ReRa E)” (Re .: CTM2014-52770-R), “Es a egias de eciclado de esiduos que con ienen
ie as a as: p ocesos de so ción median e nanocomposi es magné icos y memb anas liquidas
pa a su sepa ación y ecupe ación”(ReciRa ) (Re .: CTM2017-83581-R) and he con ac 2015
BES-2015-072506 inanced by he Spanish Minis y o Indus y and Compe i i eness.

LIST OF ACRONYMS
CA
Calcium algina e
CCD
Cen al composi e design
CMC
Ca boxyme hyl chi osan
CTAB
Ce yl ime hylammonium b omide
DMF
N,N-dime hyl o mamide
DMSO
Dime hyl sul oxide
DW
Deionized wa e
EDX
Ene gy-dispe si e X- ay spec oscopy
FE-SEM
Field emission scanning elec on mic oscopy
FT-IR
Fou ie ans o m in a ed
HREEs
Hea y a e ea h elemen s
ICP
Induc i ely coupled plasma
ILs
Ionic liquids
LREEs
Ligh a e ea h elemen s
MREEs
Middle a e ea h elemen s
NMR
Nuclea magne ic esonance
P(PTA)
Poly(py imidine- hiophene-amide)
PAs
Polyamides
REEs
Ra e ea h elemen s
REOs
Ra e ea h oxides
RSM
Response su ace me hodology
TGA
The mog a ime ic analysis
TMAPD
5,5'-( hiophene-2-ylme hylene)bis(2-aminopy imidine-4,6-
diol)
TPP
T iphenyl phosphi e
US EPA
Uni ed S a es En i onmen al P o ec ion Agency
VSM
Vib a ing sample magne ome e
XRD
X- ay di ac ion
INDEX
Page
SUMMARY………………………………………………………………………………………2
CHAPTER I: INTRODUCTION………………………………………………………….……4
Impo ance o REEs………………………………………………………………………...…4
1.1. Wha a e a e ea h elemen s?……………………..……………………………………...4
1.2. Chemical cha ac e is ics and solu ion chemis y o REEs……………………………….9
1.3. Re inemen and p oduc ion o REEs…………………………………………………....12
1.4. Heal h impac s and en i onmen al e ec s o REE exposu e..........................................14
1.5. Applica ions o REEs ………………………………………...…..….…….….………..16
1.6. C i ical issues ela ed o REEs………………………………….....................................19
1.7. Sepa a ion and eco e y o REEs……………………………………………………….25
1.8. Sepa a ion by adso p ion…………………………………………………..……..…..…25
1.8.1. Adso p ion by me al oxides………………………….……………………..…..26
1.8.2. Nano echnology and nano me al
oxides…………………………………………………………………………...26
1.8.3. Biopolyme s……………………………………………………………...…......27
1.8.4. Syn he ic me al chela ing polyme s……………….………….…………….......32
1.8.5. Syn he ic biodeg adable polyamide con aining chela ing g oups…………..….32
1.8.6. Nano echnology and nanocomposi es…………………………………….…....33
1.8.6.1. Polyme /me al oxide nanocomposi es………………………….….......34
1.8.6.2. Nano echnology and usage o magne ic sepa a ion…………………....34
CHAPTER II: SCOPE OF THE WORK ………………………….………………………....36
2.1. Scope o he wo k………………………………………………………….……………36
2.2. Objec i es ………………………………………………………………………………36
2.2.1. Syn heses and cha ac e iza ion o he magne ic nanocomposi es……………….36
2.2.2. Adso p ion s udies o Nd+3, Tb+3, and Dy+3 REEs om syn he ic aqueous
solu ions………………………………………………………………………..37
CHAPTER III: METHODOLOGY…………………………………………...………..….…38
3.1. Ma e ials and eagen s……………………………………………………...………...…38
3.2. Syn hesis o he P(PTA)………………………………………………………………...38
4
CHAPTER I
INTRODUCTION
Impo ance o REEs
In ecen decades, he applica ion o a e-ea h elemen s (REEs) has become appa en in
nume ous echnological sec o s. The ele ance o he REEs was inc easing o each a peak in
ecen yea s since hese me als play an impo an ole in he eme ging clean echnologies because
o hei excellen elec onic op ic, magne ic and ca aly ic p ope ies. Cu en ly, he e a e abou
132 million ons o REEs ese es a ound he wo ld (Gambogi, 2016). Conside ing he mine
p oduc ion, China is nowadays known as he bigges REEs p oduce while i s mine p oduc ion
a e is abou 79%. In he ollowing, Aus alia is known as he second bigges p oduce wi h a
mine p oduc ion a e o 15%. Russia, B azil, and India wi h mine p oduc ion a es o 2.2%,
1.5%, and 1.1% a e espec i ely known as he o he coun ies ha ha e he la ges amoun s o
REEs p oduc ion (Gambogi, 2016). Since China has educed i s amoun o expo , he o he
coun ies in he wo ld a e con on ing wi h a isk o supplying hei equi ed REEs. Due o he
gap in supplying he equi ed amoun s o hese elemen s and ul illing hei inc easing demands,
as well as he inc easing pollu ion o REEs, i is no only qui e necessa y o ecycle he REEs
om seconda y sou ces bu also o eco e hem om was e s eams.
1.1. Wha a e Ra e Ea h Elemen s?
Lan hanides oge he wi h scandium and y ium in he pe iodic able a e known as REEs
ha a e usually asso ed in o h ee classes, excluding p ome hium and scandium. These h ee
classes a e as ollows: (1) lan hanum (La-57), ce ium (Ce-58), p aseodymium (P -59) and
neodymium (Nd-60) as Ligh Ra e Ea h Elemen s (LREEs), (2) sama ium (Sm-62),
eu opium (Eu-63) and gadolinium (Gd-64) as middle a e ea h elemen s (MREEs) and (3) he
es o lan hanides and y ium as hea y a e ea h elemen s (HREEs) (Yan ei e al., 2016). The e
is ano he classi ica ion ha di ides REEs o LREEs and HREEs as shown in Fig. 1.1.

5
.
Fig. 1.1. Ra e ea h elemen s di ision as LREEs and HREEs (Schule e al., 2011).
Gadolinium and dysp osium a e some imes classi ied as medium-weigh lan hanides
because o hei physicochemical a ibu es. No ably, he wo d “ a e” has come om
me allu gical chemis s a ound he 1940s (Gup a and K ishnamu hy, 2004). Due o he ac ha
mos o hem a e commonly sold as oxide compounds, hey a e also known as " a e ea h
oxides”. Howe e , i can be claimed ha hey a e ha dly ound in su icien abundance in a
single place o be economically easible o mining (Chakhmou adian and Wall, 2012) since
mos o hese elemen s a e no a e wi h ega ds o he gene al amoun o hese elemen s in he
ea h's c us while hei le els in he ea h’s c us a e gene ally equal o o mo e han some
physiologically impo an elemen s like pla inum, cobal , gold, sil e , and selenium (B zyska
1996). Fig. 1.2 indica es he wo ldwide dis ibu ion o REEs while Table 1.1 p esen s he REEs
abundance in he ea h’s c us ela i e o o he o dina y me als. No ewo hy, al hough hese
abundances om Wedephol (1995) ha a e p esen ed he e a e only one o he se e al
in e p e a ions, hey can be conside ed as a gene al ep esen a i e.
As can be seen, he lan hanides con en ela i e o o he REEs in ock- o ming mine als
is no anywise a e. Mo eo e , as depic ed in Table 1.1, ce ium (60 mg/kg), lan hanum (30
mg/kg), neodymium (27 mg/kg), y ium (24 mg/kg) and scandium (16 mg/kg) can be conside ed
6
as he mos common ones. Lu e ium (0.4 mg/kg) and hulium (0.3 mg/kg) a e espec i ely he
a es elemen s while he concen a ions o he emainde s a e in he ange o 0.7 o 6.7 mg/kg.
Fig. 1.2. (A) Deposi s o REEs in he G eenland and Ame icas and (B) Deposi s o REEs in he
es o he wo ld (Ganguli and Cook, 2018).
7
Table 1.1. The abundance o elemen s in he Ea h’s c us (Wedepohl, 1995) (Bold:
Lan hanides, scandium, and y ium).
Elemen s
Abundance (pa s pe million)
Nickel (28Ni)
90
Zinc (30Zn)
79
Coppe (29Cu)
68
Ce ium (58Ce)
60
Lan hanum (57La)
30
Cobal (27Co)
30
Neodymium (60Nd)
27
Y ium (39Y)
24
Scandium (21Sc)
16
Lead (82Pb)
10
P aseodymium (59P )
6.7
Tho ium (90Th)
6
Sama ium (62Sm)
5.3
Gadolinium (64Gd)
4
Dysp osium (66Dy)
3.8
Tin (50Tn)
2.2
E bium (68E )
2.1
Y e bium (70Yb)
2
Eu opium (63Eu)
1.3
Holmium (67Ho)
0.8
Te bium (65Tb)
0.7
Lu e ium (71Lu)
0.4
Thulium (69Tm)
0.3
Sil e (47Ag)
0.08
Gold (79Au)
0.0031
P ome hium (61Pm)
10-18
Based on he o dina y pa e n o he pe iodic able, i can be s a ed ha he lan hanides
wi h e en a omic numbe s a e gene ally mo e ypical in na u e. Mo eo e , a pa e n in he
occu ence and c us al abundance o some lan hanides has been obse ed by geochemis s
(McLeod and Shaulis, 2018). I is wo h men ioning ha lan hanides ha ing lowe a omic
numbe s we e no only known as ypical ionic cons i uen s in REEs mine al o es bu also
gene ally happened in mo e conside able abundance compa ed o he lan hanide elemen s ha ing
mo e a omic numbe s (Dos al, 2017).
8
REEs we e named “ a e” due o he ac ha jus a e hey we e disco e ed, i was
hough ha only small amoun o hem was p esen in he Ea h’s c us and he e m “ea hs”
also e e s o he ac ha hei oxides ha e an ea hy appea ance. These me als a e gene ally
ound oge he in geologic deposi s because o ha ing many iden ical a ibu es ha a e used in
an ex ensi e ange o applica ions. Fo ins ance, magne s ha a e made using REEs a e no only
much mo e powe ul and weigh less bu also smalle compa ed o s anda d magne s. Mo eo e ,
some REEs can wi hs and se e e hea as well as gi ing o in ense whi e ligh when hea ed
besides ha ing g ea elec ical conduc i i y. The REEs elemen al o ms, ex ac ed om mine al
o es as oxides (i.e., REOs), a e i on-g ay o sil e y lus ous me als ha a e no mally malleable,
duc ile so and gene ally eac i e, pa icula ly when hey a e inely di ided o a ele a ed
empe a u es (Hed ick, 2004). As hey a e no na u ally p esen as pu e elemen s, e inemen
p ocesses a e needed o sepa a e hese elemen s om o es. Howe e , mo e han 200 REEs-
bea ing mine als a e known. Phospha es (xeno ime, monazi e, habdophane, ningyoi e, and
lo enci e) ollowed by ca bona es (synchysi e, bas nasi e, pa asi e, and lan hani e) a e known as
he mos common a e elemen s ha con ain o es (Oli ei a and In e no, 2014).
The main REEs mine al o es ha a e mos p ac ical o he REEs ex ac ion a e xeno ime
monazi e and bas nasi e acco ding o he ollowing desc ip ion: Bas nasi e, which is he mos
abundan one compa ed o he o he h ee REEs mine al o es, is a ca bona e mine al ha is
mos ly ound in en iched LREEs (like lan hanum, y ium, and ce ium). Bas nasi e is mainly
ound in pegma i es, ein deposi s, and con ac me amo phic zones and o ms in ocks o
ca bona e-silica e associa ed o alkaline in usions (Gup a and K ishnamu hy, 2004). Al hough
LREEs ce ium, neodymium, and lan hanum a e gene ally used o en ich monazi e, hey can also
include HREEs, especially y ium (Ni e al., 1995). The LREEs p edominance is because o he
lowe p essu es and c ys alliza ion empe a u e o his mine al while i also has mo e HREEs
compa ed o he bas nasi e o e deposi s. I mus be no ed ha i gene ally happens in
me amo phic ocks, acidic igneous ocks (mainly pegma i es) and some ein deposi s. Monazi e
is no only esis an o wea he ing bu also happens in se e al place deposi s while he hos
ocks a e e oded. Tho ium can be also ela ed o monazi e in di e en amoun s (Chen e al.,
2017). While xeno ime is c ys allized unde highe p essu es and empe a u es compa ed o
monazi e, i s c ys alline s uc u e can eadily accommoda e a highe a io o HREEs ( e bium
h ough y ium and lu e ium) compa ed o he one ha is gene ally ound in monazi e. I is
9
basically a y ium phospha e mine al and happens as a mino elemen o gneissic and g ani ic
ocks. In spi e o he ac ha i is no always p esen in ema kable quan i ies, ho ium and
u anium can also happen as elemen s o xeno ime (Pei ó and Méndez, 2013). Mo eo e , i has
been seen ha ligh a e ea hs (gene ally wi h coo dina ion numbe s o 8 o 10) concen a e on
phospha es and ca bona es. On he o he hand, hea y a e ea hs (gene ally wi h coo dina ion
numbe s o 6 o 8) concen a e on oxides and phospha es (E ans 1997).
1.2. Chemical cha ac e is ics and solu ion chemis y o REEs
In o de o illus a e he esemblance o he a e ea h me als, i is necessa y o conside
he s uc u e o hei a oms. In his ega d, all o hem ha e h ee elec ons in hei ou e mos
shell while hei chemical beha io is also de e mined using hese elec ons. Thei di e ence
e e s o hei inne shell -4 , wi h he sys ema ic illing o o bi al, as well as 5d, 6s and 6p a e
emp y. In spi e o ce ium ha can exis as Ce+4 and Eu+2, happening in bo h he i alen and
di alen s a es, all lan hanides happen as Ln+3 in aqua ic sys ems. In con a y o he di alen ions,
i alen ones a e enough s able (Topp, 1965). These ions a e speci ied using la ge ionic adii
which means ha subs i u ion eac ions no only equi e la ge ca ions, like s on ium o calcium
join ly wi h hei high alence bu also end o be sepa a ed om o he i alen ions.
Fu he mo e, he ionic adii o lan hanides educes om La+3 o Lu+3. These ions a e
undamen ally sphe ical and able o o m complexes ha a e simila o alkaline and alkaline
ea h ions besides being e y elec oposi i e. The e o e, hei bonding a ibu es a e mos ly ionic
(Hende son, 1996). The ions ha e low pola izabili y due o hei high z/ a io. They a e usually
ound in solids wi h coo dina ion numbe 8, while he smalle Sc+3 is ound in coo dina ion
numbe o 6. Howe e , Ln(H2O)63+ is he mos common lan hanide which ends o bind he wa e
molecules (B ookins, 1989). Al hough he hyd olysis o hese ions is sligh , hei hyd a ion is
inc eased wi h he a omic numbe . In his ega d, he hyd a ed ion size is inc eased om La o
Lu while hyd olysis below pH 5 seems o be insigni ican . Consequen ly, he lan hanide species
a e no easily hyd olyzed. The Ln(OH)2+, Ln(OH)3 and Ln(OH)4- s epwise o ma ional cons an s
a e signi ican ly dec eased while Ln+3 may be he dominan o m in he wa e a acidic o neu al
pH media.
Se e al complexes a e impo an and pH-speci ic, depending on he ionic media and pH
ange. MEDUSA so wa e is applied o unde s and he specia ion o me als in dilu e solu ions

10
(Puigdomenech, 2000). Fo ins ance, in Fig. 1.3A, when he solu ion con ains mul i-me als in he
p esence o H2SO4, a he pH nea 6, Tb3+ and TbSO4+ a e he impo an ionic species while in
he case o Dy3+ and Nd3+, he o ma ion anges o ionic species a e di e en depending on he
ype o REE. By inc easing pH o he solu ion om a ound 6 o Tb3+ and Dy3+ and a ound 7 o
Nd3+, Tb(OH)3 (s), Dy(OH)3 (s) and Nd(OH)3 (s) a e o med and hei amoun s a e inc eased by
inc easing pH o he solu ion up o 12. As depic ed in Figs. 1.3B and 3C, when he concen a ion
o SO42- inc eases in he solu ion, Tb3+ is changed o TbSO4+, Tb(SO4)2- and Tb(OH)3 depending
on he pH o he solu ion. Simila esul s a e seen o Tb3+ and Dy3+ which demons a e ha he
concen a ion o eagen can a ec he ypes o complexes, hei o ma ion anges, and ac ions
in he solu ion. In Figs. 1.3D-F, by changing he eagen o HNO3, di e en condi ions a e
ob ained when o he condi ions a e cons an ha indica es he ype o eagen has an impo an
e ec on he ype o ions in he solu ion. I can be concluded ha he ype o eagen and i s
concen a ion is impo an as i can a ec on he complex ypes and hei o ma ion anges
acco ding o he pH alue, also hei ac ions in he solu ion. I can be obse ed om he Figs.
1.3A-F ha pH ≤ 5.5 and low concen a ion o NO3- p e en he o ma ion o complexes. The
impo ance o he halide complexes o he lan hanides is mino , e en a low pH. Gene ally, a
basic pH, hyd olysis becomes mo e signi ican o i alen ions, Ln(OH)3 and Ln(OH)2+ (Topp,
1965). In he e minology o Pea son, he lan hanides a e known as ha d acids and can
p e e en ially bond wi h ha d bases con aining oxygen as dono a oms. The majo ligands
gene ally include a leas one dono oxygen a om, and kine ically, a e ea hs eac quickly o
o m complexes. Table 1.2 con ains some cha ac e is ics o REEs.
11
Fig. 1.3. Species o Nd3+, Tb3+, and Dy3+ (A) in he concen a ion o 1 mM SO42-, (B) in he
concen a ion o 10 mM SO42-, (C) in he concen a ion o 100 mM SO42-, (D) in he
concen a ion o 1 mM NO3-, (E) in he concen a ion o 10 mM NO3-, and (F) in he
concen a ion o 100 mM NO3-.
12
Table 1.2. Some cha ac e is ics o REEs.
Symbol
Elemen
A omic
numbe
Molecula
weigh
Ionic adii (pm)
Coo dina ion
numbe =6
Elec onic
con igu a ion
Y
Y ium
39
88.91
104
[K ]4d15s2
La
Lan hanum
57
138.9
117.2
[Xe]5d16s2
Ce
Ce ium
58
140.1
115
[Xe]4 26s2
P
P aseodymium
59
140.9
113
[Xe]4 36s2
Nd
Neodymium
60
144.2
112.3
[Xe]4 46s2
Sm
Sama ium
61
147
109.8
[Xe]4 56s2
Pm
P ome hium
62
150.4
111
[Xe]4 66s2
Eu
Eu opium
63
152
108.7
[Xe]4 76s2
Gd
Gadolinium
64
157.3
107.8
[Xe]4 7d16s2
Tb
Te bium
65
158.9
106.3
[Xe]4 96s2
Dy
Dysp osium
66
162.5
105.2
[Xe]4 106s2
Ho
Holmium
67
164.9
104.1
[Xe]4 116s2
E
E bium
68
167.3
103
[Xe]4 126s2
Tm
Thulium
69
168.9
102
[Xe]4 136s2
Yb
Y e bium
70
173
100.8
[Xe]4 146s2
Lu
Lu e ium
71
175
100.1
[Xe]4 145d16s2
The ionic adii o Ce4+ and Eu2+ is 101 and 131 pm, espec i ely.
1.3. Re inemen and p oduc ion o REEs
REEs a e sepa a ed as ecognizable elemen s due o he physical simila i ies in he a omic
adius and cha ge be ween hem. I is wo h men ioning ha be o e ecen ad ances ha made
sepa a ion economically p ac ical, no common echnological use was ound o REEs (Ha ch,
2012). Due o he ac ha hese REEs a e low in abundance in ock deposi s, hei sepa a ion is
e y di icul . The e o e, i can be concluded ha besides hei low abundance in many ock
deposi s, REEs we e no able o ind common use in echnologies be o e ecen de elopmen s
ha made sepa a ion economically p ac ical. Thei simila i y signi ies ha al hough hey can
make good subs i u es o one ano he while hei applica ions di e conside ably o he o e all
g oup (Koe h-Bake , 2012).
Gene ally, p oduc ion o REEs includes some s eps as ollows: ex ac ion o REEs ha
con ain mine al, milling, lo a ion, pu i ica ion and subsequen p ocessing o he o e (Schüle e
al., 2011). Mo eo e , REEs a e p incipally a ailable as oxidic compounds and he esou ces a e
mos ly ep esen ed as REOs because o hei s ong a ini y wi h oxygen. P ocessing REOs in o
13
u ilizable p oduc s is no only a e y complica ed p ocedu e bu also signi ican ly di e en
be ween deposi s. The main ac o s ha a ec he selec ion o ea men p ocesses a e
men ioned as ollowing (Fe on e al., 1991):
 Na u e and ype o he deposi s (like ein ype, beach sand, complex o es and igneous)
and hei complexi y.
 Na u e and ype o o he p ecious mine als ha a e a ailable wi h REOs.
 Na u e and ype o gangue mine als ha a e a ailable in he deposi (like clay, slimes and
soluble gangue).
 Composi ion and ype o he exclusi e REO mine als.
 The accessabili y o he p ocess in en i onmen al and social e ms.
Di e en chemical echniques and some imes housands o s eps a e equi ed o occu
e inemen ia physical sepa a ion o he REEs. Unluckily, all REEs and hei pa icula o es a e
a ious and he e o e need a ious chemical me hods o e ining (acco ding o he apo
p essu e and mel ing poin along wi h o he physical a ibu es o he elemen ) (Tiesman, 2010).
Gene ally, sepa a ion and concen a ion om he hos ma e ial in alkaline o acidic solu ions, he
indi idual REOs educ ion in o pu e me als, and REO sepa a ion u ilizing ion exchange o
sol en ex ac ion a e known as he undamen al s eps in REOs p ocessing (Gup a and
K ishnamu hy, 2004). The p ima y s ep commonly con ains g inding and c ushing whe e o e is
educed o ine pa icles and REO is sepa a ed using di e en me hods like magne ic, lo a ion o
g a ime ic sepa a ion. The pe cen age o REOs in he wo king ma e ial is d ama ically
inc eased along wi h he sepa a ion p ocess.
The aim o he ollowing s eps in he p ocess is o change he concen a ed mine al in o a
mo e p ecious chemical ha is o med ia di e en chemical and he mal eac ions. The mine al
concen a es a e ypically sepa a ed in o u ilizable oxides by employing hyd ome allu gy
me hods (like p ecipi a ion, leaching, and ex ac ion). Mo eo e , he oxides o me al mix u es
can be e ined in o high-pu i y a e ea h me als using me hods like he me allo he mic educ ion
o u he p ocessing (Suli e al., 2017).
Hyd ome allu gy is he mos ypical chemical ex ac ion echnique ha is used o he
sepa a ion o indi idual REOs om he mine al concen a e. Basici y a ia ions be ween he
di e en a e ea hs a ec he hyd olysis o ions, he sol abili y o hei sal s and he c ea ion o
complica ed species (Gup a and K ishnamu hy, 2004). In his ega d, ac ional c ys alliza ion,
20
en i onmen . Flo a ion in ol es chemical bene icia ion in ponds, known as ailings. The
eminde s, like adioac i e ho ium o u anium o he chemicals, a e le in he was ewa e .
Conside ing he ac ha his wa e is exposed o dis up ions o na u al en i onmen al condi ions,
i can pose c i ical isks o en i onmen al pollu ion (Schüle e al., 2011). Mo eo e , al hough
pu i ica ion is cos ly and ene gy-in ensi e, i is c ucial due o he pu i y o 99% ha is almos
equi ed (Ha ch, 2012). The p oblem in he p oduc ion s ep o REEs is no he only one.
Al hough REEs a e ex ensi ely u ilized in plen y o applica ions a ound he wo ld,
supplying hem is conside ably limi ed o only a ew la ge mining dis ic s (Chakhmou adlan and
Wall, 2012). In spi e o he ac ha REEs occu a ound he wo ld, he la ges mining ields o
o es, such as monazi e, bas näsi e, and xeno ime ha ing essen ial REEs, a e loca ed in he Asian
s a es (Manchen e al., 2019) and among hem, China is changed o he i s coun y in mining
and ex ac ing REEs due o hei mos abundan REE deposi s. As can be seen in Table 1.7,
mo e han 90 % o mine p oduc ion o a e ea h occu s in China, al hough his coun y has less
han 40 % o he iden i ied deposi s. While China's domes ic demand has ema kably inc eased,
i igh ened i s REEs expo quo a om 50145 onnes o only 31130 onnes om 2009 o 2012
which led o se ious p oblems o REEs use s ha we e ou side o China (I was p o ed by he
a e-ea h c isis in 2011 wi h he eco d o he highes p ices) (Binnemans e al., 2013).
Table 1.7. Wo ld a e ea h elemen p oduc ion and a e ea h s o es es ima ion, 2012 (Lucas
e al., 2015).
Coun y
Mine P oduc ion o
REEs
(Kilo onnes)
Deposi s o Ra e
Ea h Elemen s
(Mega onnes)
China
75
44
USA
1
13
Aus alia (mined and
concen a ed in Aus alia,
ex ac ed in Malaysia)
1
1
India
3
2
O he
33
In 2018, he o al wo ld REE deposi s we e es ima ed o be a ound 120 million ons
(Table 1.8) (Manchen e al., 2019) which seems o be su icien o global equi emen s o e
hund eds o yea s (Zhou e al., 2017). Howe e , he REEs wo ld demand was abou 142
housand ons in 2018 (Manchen e al., 2019).

21
Table 1.8. Wo ld mine p oduc ion and ese es o REEs* (U.S. Geological Su ey, 2019).
Coun y
Mine p oduc ion
Rese es
2017
2018
Uni ed S a es
-
15000
1400000
Aus alia
19000
20000
3400000
B azil
1700
1000
22000000
Bu ma (Myanma )
No a ailable
5000
No a ailable
Bu undi
-
1000
No a ailable
China
105000
120000
44000000
India
1800
1800
6900000
Malaysia
180
200
30000
Russia
2600
2600
12000000
Thailand
1300
1000
No a ailable
Vie nam
200
400
22000000
O he coun ies
-
-
4400000
Wo ld o al ( ounded)
132000
170000
120000000
*Da a in me ic ons o REEs oxide
I is wo h men ioning ha no only China has he mos ex ensi e deposi s o REEs bu
also i has he mos complica ed p ocessing echnologies and acili ies o p oducing he a e
ea h me als. Each yea , China can p oduce a ound 120,000 ons o a e ea h while he o al
wo ld p oduc ion is abou 170,000 ons (Manchen e al., 2019, Zhou e al., 2016). Al hough
mining in o he coun ies (like he USA, India, and Aus alia) is g owing, i s p ocess is e y
slow. The peak o all a e ea hs p ices was in 2011 and a e ha hei p ices ha e allen down
which had a discou aging impac on new mining p ojec s (Gambogi, 2013). This si ua ion has
also mo i a ed o he coun ies like Japan and mos EU Membe S a es ha do no ha e any kind
o main a e-ea h ese es on hei e i o y o sea ch o seconda y and al e na i e a e ea h
esou ces o de eloping hei own a e-ea h indus y o acqui e a sou ce o bo h hea y and ligh
a e ea hs (Binnemans e al., 2013). Using na u al esou ces is essen ial in a sus ainable and
ci cula economy. This can only happen by ecycling and eusing ma e ials om end-o -li e
consume goods.
REEs a e conside ed as he mos c ucial aw ma e ials g oup wi h he highes supply isk
by he Eu opean Commission (Eu opean Commission C i ical aw ma e ials o he EU). To
o e come he challenge o supplying he REEs, a h ee old me hod can be sugges ed. The i s
s a egy is o subs i u e c ucial a e ea hs by less c ucial me als. Secondly, he isk o supplying
REEs can be educed by in es ing in sus ainable undamen al mining om new o old REEs
22
ese es. Nowadays, mining companies a e now ex ensi ely looking o new usable a e ea h
ese es and old mines a e being opened again (Humph ies, 2012). P io o he REEs mining
boom in China, he global ma ke was domina ed by he US. The ope a ions we e s a ed by
Moun ain Pass in Cali o nia in 1965 (Fig. 1.6) and i was known as he main p oduce a ound he
wo ld o decades (Ba akos, 2017). No ably, because o he con es in China as well as in
esponse o en i onmen al ma e s in he su ounding a ea o Moun ain Pass, mining ac i i ies
s opped in 1998 (Manche i, 2015). The p oduc ion was es a ed in 2012 due o he REEs supply
isk. None heless, mos o he coun ies ha e o in es in echnosphe ic mining due o he
absence o ope a ional and/o economic p ima y ese es on hei e i o y (Johansson e al.,
2013).
Fig. 1.6. Molyco p Moun ain Pass a e ea h acili y in Cali o nia's Moja e Dese .
Gene ally, echnosphe ic mining can ha e many o ms. Wi h conside a ion o c ucial
me al-ha ing s eams, such mining con ains (1) di ec ecycling o p e-consume manu ac u ing
REEs esidues/sc ap; (2) u ban mining o pos -consume (usually complica ed mul i-ma e ial)
End-o -Li e p oduc s; (3) land ill mining o his o ic (and u u e) u ban and indus ial was e
esidues ha ing REEs. The ocus o u ban mining and di ec ecycling is on esou ces wi h e y
g ea con en o a e ea hs. Howe e , he o al accessible olumes o ecycling a e ela i ely
low. Howe e , base me als like i on, coppe , and aluminum along wi h aluable me als (sil e ,
gold, and pla inum-g oup me als) achie ed high ecycling a es. In spi e o he ac ha he e is
an ex ensi e li e a u e dealing wi h (mos ly lab-scale) esea ch a emp s on ecycling REEs, only
23
less han 1% o hem we e being ecycled in 2011. This is gene ally because o ine ec i e
collec ion, lack o incen i es, and echnological di icul ies (Binnemans e al., 2013).
Gene ally, neodymium, dysp osium, eu opium, y ium, and e bium (Fig. 1.7) a e known
as he i e mos c i ical REEs based on he medium- e m c i icali y ma ix o he U.S.
Depa men o Ene gy (DOE), and hei essen ial applica ions a e in g een ene gy as ollows
(Binnemans e al., 2013; US Depa men o Ene gy, 2011):
• Dysp osium and neodymium a e u ilized in he pe manen magne s manu ac u ing which a e
employed in wind u bines and many o he p oduc s like speake s, ha d disk d i es, and
headphones.
• Y ium, eu opium, and e bium a e u ilized besides ce ium, lan hanum, and gadolinium in
phospho s in low-ene gy luo escen lamps.
• Y ium, neodymium, lan hanum, ce ium, and p aseodymium a e u ilized in he manu ac u ing
o nickel me al hyd ide (NiMH) ba e ies o hyb id ehicles.
In addi ion, hei haza ds a e men ioned in Table 1.9. Consequen ly, ecycling REEs
om end-use p oduc s, such as luo escen lamps and magne s ha p esen o e 70% o he
a e-ea h ma ke in e ms o alue (32% o lamp phospho s; 38% o magne s), can p o ide he
oppo uni y o main ain he supply o hese c ucial elemen s and dec ease he dependency o UE
om o he coun ies. In his con ex , he e is a necessi y o de elop ad anced sepa a ion
p ocesses o eco e y o Nd, Dy, and Tb which a e h ee o he mos c i ical elemen s.
24
Fig. 1.7. DOE medium e m (2015-2025) c i icali y ma ix, ep esen ing he i e mos c ucial
a e-ea h elemen s (Nd, Y, Tb, Eu, Dy).
Table 1.9. Signi ican uses o Dy, Nd, and Tb and hei oxicological in o ma ion (Rim e al.,
2013).
Elemen
Toxicological in o ma ion
Dy
Soluble Dy sal s, like dysp osium ni a e and chlo ide, a e
mildly oxic when inges ed. Howe e , he insoluble sal s a e
non- oxic. Acco ding o he oxici y o dysp osium chlo ide o
mice, i is de e mined ha he inges ion o 500 g o mo e migh
be a al o a human.
Nd
Nd compounds a e o low o mode a e oxici y. None heless, i s
oxici y has no been explo ed ho oughly. Neodymium sal s a e
e y i i a ing o he mucous memb anes and eyes, and
mode a ely i i a ing o he skin.
Tb
I may cause se ious i i a ion o he skin and eyes.
25
1.7. Sepa a ion and eco e y o REEs
Indi idual REEs pu i ica ion has ob ained ema kable a en ion in ecen yea s due o he
g owing equi emen s o high-pu i y REEs and hei compounds (Anas opoulos e al., 2016).
Se e al echniques a e used o he sepa a ion and eco e y o me al ions om aqueous solu ion,
like chemical p ecipi a ion, memb ane echnology, and ex ac ion o sol en .
Among he di e en sepa a ion echniques, sol en ex ac ion is ex ensi ely used o
aqueous solu ions ea men con aining me al ions. Howe e , i is cos ly on a la ge scale and
yields o ex ensi e en i onmen al p oblems due o he oxic o ganic diluen s and modi ie s ha
a e widely used (Yada e al., 2015). The pu i ica ion and sepa a ion o REEs using sol en
ex ac ion need he ea men o a la ge olume o dange ous ola ile o ganic compound sol en s
(Flo ek e al., 2014). Since lammable ola ile o ganic compound sol en s a e conce ned, sol en
ex ac ion seems o be dange ous.
Chemical p ecipi a ion also needs an ex ensi e amoun o chemicals o dec ease me als o
a sa is ac o y discha ge le el. Ex eme sludge p oduc ion is known as i s o he d awbacks which
needs mo e ea men , poo se ling, slow p ecipi a ion o me al, me al p ecipi a es agg ega ion,
and he long- e m en i onmen al e ec s o sludge disposal (Aziz e al., 2008). High ene gy
consump ion ela ed o he high ope a ion p essu es, he cos s associa ed wi h ouling p oblems,
and eplacemen o memb anes can be conside ed as he main d awbacks o memb ane
echnology.
1.8. Sepa a ion by adso p ion
Adso p ion can be conside ed highly e ec i e, especially because o dilu e solu ions,
cheap and easy echniques and being able o s a en i onmen ally wi hou u ilizing any o ganic
sol en s o eco e y o me al ions om aqueous solu ion. The e o e, i can be conside ed as a
compe i i e al e na i e o sol en ex ac ion. Some adso ben s ha e been used o a e ea h
me als adso p ion, such as Sa gassum sp (Oli ei a e al, 2011) ac i a ed ca bon (Mu y e al.,
1996), i anium dioxide (Liang e al., 2001), cellulose (Zhu e al., 2015), b-cyclodex in (Zhao e
al., 2016), silica (Esse e al., 1994), aminoca boxylic adso ben s (G ebne a e al., 1996), and
oxidized mul iwalled ca bon nano ubes (Koochaki-Mohammadpou e al., 2014), SiO2/UF
imp egna ed wi h o ganophospho us ex ac an (Nase e al., 2015), ac i a ed biocha s om
cac us ib es (Hadji o i, 2016), g aphene oxide-co n zein composi es (Xu e al., 2018) .

26
Due o some disad an ages ha a e a ailable in he adso ben s which ha e been used o
adso p ion o REEs, such as low adso p ion capaci y, weak mechanical p ope ies, poo chemical
esis ance, di icul adso ben sepa a ion om he aqueous phase, and high-dose equi emen o
he adso ben o comple e me al ions emo al, i is necessa y o pe o m ex ensi e
in es iga ions on he p oduc ion o no el adso ben s o o e come such de ec s. The selec ion o
adso ben elies on he na u e o he me al ion, as each ype o me al may need a pa icula
adso ben . On he o he hand, adso p ion e iciency elies on physicochemical a ibu es, such as
unc ional g oups, po osi y, pa icula su ace a ea, and adso ben pa icle size (Chen e al 2003).
1.8.1. Adso p ion by me al oxides
Gene ally, he high su ace a ea and high speci ic a ini y o adso ben a e he wo key
ac o s o de e mine he e iciency o me al ion sepa a ion om pollu ed wa e . Me al oxides a e
a ac i e candida es as adso ben s o me al ion sepa a ion and eco e y (Ri mann e al., 2011).
The high su ace a ea o me al oxides may p o ide ich si es o me al ion adso p ion which is
no mally bene i ed om po ous s uc u es. The high speci ic a ini y is mainly due o he
abundan su ace hyd oxyls on me al oxides (Qu, 2008). Some me al oxides ha e been used as
an adso ben o adso p ion o REEs, such as Al2O3 (Ma mie e al., 1997), amo phous silica
(Ma mie e al., 1999), and α-TiO2 (Ridley e al., 2005). The in es iga ions showed ha me al
oxides a e no only cheap and non oxic bu also chemically s able and en i onmen ally iendly
(Chu e al., 2009). None heless, esea che s all a ound he wo ld ha e been ying o dec ease he
main disad an age o me al oxides, such as no being easily dispe sed in aqueous solu ion
because o being mic osized. Besides, by inc easing pa icle size, he a io o su ace a ea o
olume declines; he e o e, he capaci y o me al adso p ion dec eases.
1.8.2. Nano echnology and nano me al oxides
Nanos uc u ed ma e ials wi h dimensions (g ain size, laye shapes o hickness below
100 nm) ha e yielded o he g owing in e es in nano echnology (Ho nyak e al., 2009). The
eccen ic a ibu es o nanoma e ials a e ela ed o hei nano-dimensions. In ac , nanoma e ials
a e he ma e ials ha ha e a leas one dimension which is below 100 nm (Cha opadhyay e al.,
2009).
27
Du ing he las wo decades, a lo o a emp s ha e been done a ound he wo ld in bo h
he heo y and he empi ical esea ch o he de elopmen , speci ica ion and applica ions o
ino ganic nanos uc u es con aining me al oxides, composi es and ce amics and hey ha e
yielded o a ma u e and mul idisciplina y ield. Nanos uc u ed ma e ials a e gene ally known
because o hei g een chemis y, s abili y, and a ious echnical applica ions (Bhushan e al.,
2010).
Amongs ino ganic nanos uc u es, me al oxides nanos uc u es ha e ecei ed so much
a en ion in ecen yea s. They a e applied in e sa ile applica ions, such as gas senso s, op ical
senso s, p essu e senso s, elec ochemical pe o mance o ene gy s o age, ca aly ic and
pho oca aly ic, en i onmen al applica ion, e c. Sepa a ion o me al ions om pollu ed wa e s by
he adso p ion p ocess is known as one o he mos impo an en i onmen al applica ions o
me al oxides nanos uc u es ha has been in es iga ed by many esea che s. Thei majo bene i s
include hei abili y o be simply dispe sed in aqueous solu ion and he exis ence o a la ge
numbe o hei a oms, known as su ace a oms, which no only ha e high adso p ion capaci ies
o many me al ion bu also a e unsa u a ed. In addi ion, he ex emely small size o nanopa icles
c ea es a la ge su ace a ea in ela ion o hei olume and makes hem highly eac i e in
compa ison o non-nano o ms o he same adso ben s (S i as a a e al., 2015). The adso p ion
beha io o nanome al oxides, such as nickel oxide (Saik ishna and Babu, 2015), aluminum
oxide (Pa a e al., 2012), i anium oxide (Jegadeesan e al., 2010), and zi conium oxide
(H is o ski e al., 2008) ha e been p o ed by he esea che s including he me als ha we e
adso bed by aluminum oxide, i anium oxide, and zi conium oxide om he pape s men ioned
abo e. The p ima y mechanisms o adso p ion o REEs on nanos uc u ed ma e ials, like me al
oxides, a e su ace complexa ion, p ecipi a ion, ion exchange, physical adso p ion, and
elec os a ic a ac ion.
1.8.3. Biopolyme s
Biopolyme s a e polyme s p oduced om biobased ma e ials ha a e also biodeg adable.
Biopolyme ic ma e ials con ain algina es, cellulose, p o eins, lignins, ca ageenan, chi osan, and
chi in de i a i es. The salien a ibu e o biopolyme s is ha hey own a g ea amoun o a ious
unc ional g oups like amines and hyd oxyls ha can enable me al ions o bind ei he by
chemiso p ion o physiso p ion (Sa a anan and Sudha, 2014).
28
Amongs he biopolyme s in es iga ed o me al ions adso p ion, algina e and chi osan as
na u al ca bohyd a e biopolyme s a e indus ially and scien i ically a ac i e and ha e ecei ed
so much a en ion as adso ben and complexing agen by hei unc ional g oups ha ha e a
s ong a ini y o hea y me al ions. Due o he ac ha na u al ma e ials, which a e accessible in
g ea quan i ies, o pa icula was es ob ained om manu ac u ing ope a ions, a e ex ensi ely
a ailable, en i onmen ally iendly and p ac ically unexploi ed esou ces, hey may ha e a g ea
po en ial o be u ilized as low-cos adso ben s (Spinelli e al., 2004).
Algina e
Algina e, a na u al polysaccha ide, is he bina y copolyme o (1,4) glycosidically linked
α-D-mannu onic acid (M) and β-L-gulu onic acid (G) (Fig. 1.8). The abundance o ca boxylic
and hyd oxyl g oups gi es algina e s ong chela ing p ope ies o me al ions (Fise e al., 2008).
I is nega i ely cha ged in aqueous solu ion a pH > 3.4 owing o he ca boxyl g oups a ailable in
bo h M and G subuni s, whe e he ca boxyl g oups a e dep o ona ed excluding a e y low pH
(Yu e al., 2013). Poly alen ca ions can in e ac wi h blocks o M and G esidues coope a i ely
in he gela ion p ocess o c ea e ionic c oss-links be ween a ious polyme chains (Fig. 1.9) ha
is known as “egg-box” model (B accini and Pé ez, 2001). The poly alen ca ions, like calcium
ca ions, can be subs i u ed by ionic adso ba es. Because o hei abili y o o m s able s uc u es,
c oss-linked algina e has been u ilized o he adso p ion o hea y me als, like lead (Yakup A ıca
e al., 2003), me cu y (Yakup A ıca e al., 2004), manganese (Go oh e al., 2004), and ch omium
(Ibáñez and Ume su, 2004). Algina e adso ben s ha e been also used o he REEs adso p ion,
such as sodium algina e hyd ogel c oss-linked wi h poly-γ-glu ama e (Xu e al., 2015), calcium
algina e beads (Nayak, 2005), and algina e–poly glu amic acid hyb id gels (Wang e al., 2014).
The p ima y binding mechanism o me al ions o calcium-algina e gel beads con ains ion
exchange and adso p ion. Addi ionally, new hypo heses o ca ion binding and algina e c oss-
linking (Siew e al., 2005) ha e been explo ed in ecen s udies. Based on hem, only one o wo
M and G blocks a e in ol ed in c ea ing a binding si e. Mo eo e , Rod igues and Lagoa
p oposed ha he numbe o binding si es and binding mechanisms elied on he accessibili y o
ca ion in he solu ion (Rod igues and Lagoa, 2006). Resul s showed he success ul usabili y o
algina e adso ben s o sepa a e REEs om aqueous solu ion.
29
Fig. 1.8. Gulu onic acid (G) and Mannu onic acid (M) subuni s in he chemical s uc u e o
algina e a pH>3.4 (Yu e al., 2013).
Fig. 1.9. Gela ion p ocess by a di alen ca ion (B accini and Pé ez, 2001).
Chi osan
Chi osan, a ca ionic polysaccha ide composed o N-ace yl glucosamine and glucosamine
subuni s (Fig. 1.10), is a po en ial biopolyme acqui ed cos -e ec i ely by he de i a ion o
chi in, which is a na u al ma e ial ex ensi ely ound in c us acean shells and is p o ed o ha e
he bes chela ing p ope ies among o he na u al polyme s (Va ma e al., 2004). I has also been
ex ensi ely aken in o conside a ion du ing he las decade o hea y me als adso p ion om
aqueous solu ion due o i s unique p ope ies, especially abundan amine (NH2) and hyd oxyl
(OH) g oups. The amine g oups in he s uc u e o chi osan a e gene ally conside ed p ima y
ac i e si es o adso p ion o he me al ion. In addi ion o amine g oups, hyd oxyl g oups may
con ibu e o adso b me al ion. Chi osan is posi i ely cha ged a pH < 6.5 owing o he abundan
a ailabili y o amine g oups ha a e p o ona ed a low pH (Yu e al., 2013). Mo eo e , chi osan
36
CHAPTER II
SCOPE OF THE WORK
2.1. Scope o he wo k
The objec i e o his p ojec is o in es iga e he sepa a ion/ eco e y o he Tb+3, Dy+3,
and Nd+3 om aqueous solu ion by syn hesizing no el magne ic nanocomposi es using wo
biopolyme s o a biopolyme mixed wi h a syn he ic chela ing polyme ha ing di e en
unc ional g oups, and magne ic nanopa icles. Fo hese pu poses, calcium algina e (CA),
caboxyme hyl chi osan (CMC), and a no el syn he ic biodeg adable poly(py imidine- hiophene-
amide) (P(PTA)) will be used o p oduce new nanocomposi es ha a e g een, en i onmen al-
iendly, and easy sepa able om aqueous media by an ex e nal magne ic ield.
Such magne ic polyme ic nanocomposi es a e expec ed o ha e some ad an ages, such as
easy sepa a ion om aqueous solu ion, a ou able adso p ion capaci y because o ha ing
di e en unc ional g oups, a ou able chemical esis ance, and less agglome a ion in aqueous
solu ion. The new magne ic nanocomposi es will be s udied o he sepa a ion/ eco e y o Nd+3,
Tb+3, and Dy+3 selec ed among he REEs ha a e c i ical me als wi h a high isk o supply.
2.2. Objec i es
2.2.1. Syn heses and cha ac e iza ion o he magne ic nanocomposi es
The magne ic nanopa icles (Ni0.2Zn0.2Fe2.6O4) nanocomposi es will be syn hesized by
hyd o he mal me hod o be used o he syn hesis o he magne ic
P(PTA), a no el syn he ic biodeg adable polyamide, will be syn hesized by polycondensa ion o
a diamine-phenol in 1,3-dip opyl imidazolium b omide ionic liquid as a sol en o a oid he use
o he oxic iphenyl phosphi e/N-me hylpy olidone/py idine/LiCl ha is equi ed in he
con en ional di ec polycondensa ion.
The syn heses o he CA/CMC/Ni0.2Zn0.2Fe2.6O4, CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 magne ic nanocomposi es will be ca ied ou by gela ion
echnique, and he P(PTA)/Ni0.2Zn0.2Fe2.6O4 will be syn hesized by hyd o he mal echnique.
To cha ac e ize he ma e ials de eloped, a ious echniques will be used, including
nuclea magne ic esonance (NMR), X- ay di ac ion (XRD), ield emission scanning elec on

37
mic oscopy (FE-SEM), Ene gy-dispe si e X- ay spec oscopy (EDX), he mog a ime ic
analysis (TGA), ib a ing sample magne ome e (VSM), and Fou ie ans o m in a ed (FT-IR).
2.2.2. Adso p ion s udies o Nd+3, Tb+3, Dy+3 REEs om syn he ic aqueous solu ions
In he adso p ion s udies o Nd+3, Tb+3, and Dy+3 by he syn hesized nanocomposi es, he
in luence o di e en pa ame e s such as pH, adso ben dose, con ac ime, ini ial concen a ion
o Nd+3, Tb+3, and Dy+3, ionic s eng h on he adso p ion e iciency will be in es iga ed in single
and e na y ba ch modes.
The adso p ion kine ic and iso he m models will be applied o i ing he expe imen al
adso p ion da a. The e ec o empe a u e on he adso p ion p ocess o Nd+3, Tb+3, and Dy+3, will
be s udied and he modynamic pa ame e s will be de e mined. In addi ion, o model he
adso p ion o he Nd+3, Tb+3, and Dy+3 in he e na y sys em, RSM-CCD will be applied. To
e alua e he eusabili y o he syn hesized nanocomposi e, adso p ion-deso p ion cycles will be
pe o med. Finally, Nd+3, Tb+3, and Dy+3 adso p ion in a ixed-bed column and i ing he
expe imen al da a by he models will be s udied.
38
CHAPTER III
METHODOLOGY
3.1. Ma e ials and eagen s
Sodium algina e and CMC we e espec i ely bough om China and PanReac
AppliChem and Nan ong Chem-Base Co. Dy(NO3)3.5H2O was pu chased om Al a Aesa .
Nd(NO3)3.6H2O, Tb(NO3)3·6H2O, Zn(NO3)2.6H2O, Fe(NO3)3.9H2O, Ni(NO3)2·6H2O,
glu a aldehyde, ce yl ime hylammonium b omide (CTAB), 2-amino-4,6-dihyd oxypy imidine,
2- hiopheneca boxaldehyde, e eph halic acid, iphenyl phosphi e (TPP), dime hyl sul oxide
(DMSO), and me hanol we e bough om Sigma-Ald ich. CaCl2, HNO3 and HCl we e bough
om PanReac AppliChem. Since he analy ical g ade o all chemicals was chosen, hey we e
u ilized wi hou u he pu ifica ion.
3.2. Syn hesis o he P(PTA)
The syn hesis o he P(PTA) was pe o med in wo s eps. Fi s ly, a diamine-phenol
monome (TMAPD) was syn hesized. Secondly, he polyme was ob ained by polycondensa ion o
TMAPD in 1,3-dip opyl imidazolium b omide ionic liquid as a sol en o a oid he use o he oxic
iphenyl phosphi e/N-me hylpy olidone/py idine/LiCl ha is equi ed in he con en ional di ec
polycondensa ion. P e iously, he 1,3-dip opyl imidazolium b omide ionic liquid (IL) was p epa ed
based on he p ocedu e epo ed by Vygodskii e al. (2004).
The p ocedu es o he syn heses o he TMAPD and P(PTA) we e as ollows:
3.2.1. Syn hesis o he monome (5,5'-( hiophene-2-ylme hylene)bis(2-aminopy imidine-4,6-
diol) (TMAPD))
TMAPD was syn hesized acco ding o he ollowing p ocedu e: A mix u e o 2.54 g (0.02
mol) 2-amino-4,6-dihyd oxypy imidine, 1 mL (0.01 mol) 2- hiopheneca boxaldehyde, and 20 mL
DMSO was s i ed o 6 h a 110 °C. While he eac ion es ed by hin-laye ch oma og aphy was
comple ed, he solu ion empe a u e was dec eased o he oom empe a u e, and he iole powde
ob ained by pou ing he solu ion in o 400 mL o cold DW (-5 °C) was il e ed, insed many imes
using DW and hen d ied using acuum o en a 100 °C. The eac ion yield was 92 % (3.20 g), and
39
he ob ained compound did no show a sha p mel ing poin and s a ed o be decomposed a abo e
300 °C. TMAPD s uc u e is shown in Fig. 3.1.
Fig. 3.1. S uc u e o TMAPD.
3.2.2. Syn hesis o he biodeg adable P(PTA) by he polycondensa ion eac ion o TMAPD in
TPP/IL
The P(PTA) was achie ed by polycondensa ion o TMAPD using TPP-IL as ca alys and
sol en by he ollowing p ocedu e: A lask o h ee-necked ound-bo omed wi h he olume o 50
mL was i ed wi h a mechanical s i e , a wa e cooled condense , and a gon gas and hen, a
mix u e con aining 1 mmol TMAPD, 1 mmol e eph halic acid, 0.7 g 1,3-dip opyl imidazolium
b omide {[1,3-(p )2im]B } as IL, and 1.29 mmol TPP was placed. The solu ion became s icky as he
eac ion con inued a 110 °C o 2.5 h. In he ollowing, he eac ion mix u e empe a u e was
dec eased o he empe a u e o he oom and he p ecipi a ion o he ob ained P(PTA) was
pe o med using 100 mL o me hanol. Then, a e he p ecipi a e il a ion, he ho wa e was used
o washing i . A e wa d, he p ecipi a e was u he e ined in a Soxhle appa a us using me hanol
o 24 h o elimina e he oligome s wi h low molecula weigh . The PA s uc u e is shown in Fig.
3.2.
Fig. 3.2. S uc u e o he P(PTA).
40
3.3. Syn hesis o he magne ic nanopa icles
Hyd o he mal me hod was used o syn hesize he Ni0.2Zn0.2Fe2.6O4 magne ic
nanopa icles. A mixed solu ion o 2.6 M Fe3+, 0.2 M Zn2+ and 0.2 M Ni2+ was made eady in
HCl solu ion and in he ollowing NaOH solu ion was added in o mixed solu ion unde ni ogen
gas while he pH alue o he mix u e was se o 10.5. The ea e , 0.3 g o CTAB was added o
his mix u e and i was hen loca ed in o an au ocla e (Te lon-lined s ainless s eel) o 8 h a 200
⁰C o an o en o pe o m hyd o he mal ea men . Then, he au ocla e empe a u e was educed
o he empe a u e o he oom na u ally, and he p ecipi a e was collec ed and insed many imes
using deionized wa e o ob ain neu al pH. Consequen ly, he ob ained pa icles we e d ied a 50
°C.
3.4. Syn hesis o he nanocomposi es
Fou di e en magne ic nanocomposi es, namely CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4,
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, CA/CMC/Ni0.2Zn0.2Fe2.6O4, and P(PTA)/Ni0.2Zn0.2Fe2.6O4, we e
syn hesized acco ding o he p ocedu es desc ibed below.
3.4.1. Syn hesis o he magne ic CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4 nanocomposi e
Sodium algina e powde was dissol ed in DW wi h a concen a ion o 1.5 % (w/ ) o
p epa e a sodium algina e solu ion. 0.5 g o P (PTA) and 0.7 g o Ni0.2Zn0.2Fe2.6O4 we e
comple ely expanded in he sodium algina e solu ion wi h se e e s i ing o 24 h o achie e a
homogeneous solu ion, A. A e wa ds, he gela ion p ocess was pe o med by adding he
solu ion A o a solu ion o CaCl2 (0.05 M) and 2 % glu a aldehyde. Then, he mix u e was s i ed
o 24 h. In he ollowing, he desi ed p oduc was accumula ed by an ex e nal magne ic ield and
insed many imes using DW un il eaching he solu ion pH o 7 and hen d ied a 50 °C. Finally,
i was powde ed.
3.4.2. Syn hesis o he magne ic CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 nanocomposi e
The magne ic nanocomposi e was syn hesized by he gela ion me hod. CMC powde was
dissol ed in deionized wa e (DW) (3 % w/ ) unde s i ing a 150 pm o 3 h o p epa e CMC
solu ion. Then, 0.5 g o he P(PTA) and 0.7 g o Ni0.2Zn0.2Fe2.6O4 we e added o CMC solu ion
and ully dispe sed wi h igo ous s i ing wi hin 24 h. The gela ion p ocess was hen pe o med
41
by adding he mix u e o a solu ion o CaCl2 (0.05 M) and 2 % glu a aldehyde. The mix u e was
s i ed o 24 h and he sepa a ion o he ob ained nanocomposi e was pe o med using an
ex e nal magne . I was also washed using deionized wa e many imes o elimina e all impu i ies
(un eac ed GA) and each he solu ion pH alue o 7. Then, he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4
bionanocomposi e was d ied a 50 °C. Ul ima ely, he ob ained p oduc was powde ed.
3.4.3. Syn hesis o he magne ic CA/CMC/Ni0.2Zn0.2Fe2.6O4 nanocomposi e
The p ocedu e o CA/CMC/Ni0.2Zn0.2Fe2.6O4 syn hesis is men ioned in he ollowing: 1 g
o sodium algina e was dissol ed in 80 mL o deionized wa e a oom empe a u e using a
labo a o y s i e . The ea e , CMC powde (0.5 g) was added in o he solu ion and mixed
homogeneously. Then, he Ni0.2Zn0.2Fe2.6O4 (0.7 g) was added o he biopolyme s mix u e. In
o de o acqui e a homogeneous blend solu ion, he magne ic and biopolyme s pa icle solu ion
was s i ed a he empe a u e o he oom o 24 h. Then, he gela ion p ocess was pe o med by
adding he mix u e o a solu ion o calcium chlo ide 0.05 M and 2 % glu a aldehyde. To sepa a e
he esul ing bionanocomposi e om solu ion, an ex e nal magne ic ield was used and hen i
was washed se e al imes wi h dis illed wa e o emo ing any emaining glu a aldehyde and
calcium chlo ide ill he pH alue o he solu ion was equal o 7. Finally, he
CA/CMC/Ni0.2Zn0.2Fe2.6O4 bionanocomposi e was d ied a 50 °C. Ul ima ely, he ob ained
p oduc was powde ed.
3.4.4. Syn hesis o he magne ic P(PTA)/Ni0.2Zn0.2Fe2.6O4 nanocomposi e
The P(PTA)/Ni0.2Zn0.2Fe2.6O4 nanocomposi e was syn hesized by hyd o he mal me hod
as ollows: 1.8 g o he P(PTA) was added o he solu ion o HCl and N,N-Dime hyl o mamide
con aining 0.2 M Ni2+, 2.6 M Fe3+, and 0.2 M Zn2+. The ea e , NaOH solu ion was added in o
he mixed solu ion unde ni ogen gas and he pH alue o he mix u e was se o 10.5. 0.3 g o
CTAB and 4 mL glu a aldehyde we e added o he mix u e and he ea e i was loca ed in o an
au ocla e (Te lon-lined s ainless s eel) o 8 h a 200 ⁰C o an o en. The au ocla e empe a u e
was hen na u ally educed o he empe a u e o he oom, and he p oduc was collec ed and
insed wi h DW se e al imes o each neu al pH. Consequen ly, he composi e was d ied a 50
⁰C.

42
3.5. Ins umen a ion and cha ac e iza ion
KB pelle was used o eco d he FT-IR spec a on a Pe kinElme , USA. The GBC
MMA ool wi h CuKα adia ion in he 2θ ange o 10–70⁰ was used o eco d he XRD pa e n.
FE-SEM (Zeiss Neon-40, Ge many) was used o speci ying he mo phology o he p oduc s.
The magne ic a ibu es o he p oduc s we e in es iga ed a he empe a u e o he oom using a
VSM (Daghigh Ka i Co po a ion, I an). Mo eo e , TGA was pe o med on a Me le
TGA/SDTA 851e/LF/1100 he mobalance. The sample empe a u e was enhanced om he
empe a u e o he oom o 1000 ⁰C ( a e=10 ⁰C/min) while ni ogen low was cons an . An
Agilen 4100 MP-AES Spec ome e was employed o analyze Nd+3, Dy+3, and Tb+3
concen a ion.
3.6. Adso p ion s udies o Nd+3, Tb+3, and Dy+3
The adso p ion beha io o Nd+3, Tb+3, and Dy+3 by he magne ic nanocomposi es was
in es iga ed in ba ch sys em o analyze he e ec s o di e en pa ame e s on he p ocess o
adso p ion and de e maine he op imum condi ions o maximum adso p ion e iciency o he
ions. In addi ion, he adso p ion o he ions was s udied in he packed-bed column.
3.6.1. Ba ch adso p ion expe imen s
Ba ch adso p ion es s we e done in 125 mL lasks con aining 50 mL solu ions wi h he
concen a ions in he ange o 30-300 mg/L ha we e made eady om he dilu ion o 1000 mg/L
s ock solu ions o he me al ions a 180 pm. The alues o pH we e egula ed ia adding a
sui able amoun o 0.1 M sodium hyd oxide o ni ic acid solu ions and moni o ed by a pH
me e . While he con ac ime was inished, a magne ic ield was used o sepa a e he adso ben
and he esidual Nd+3, Tb+3, and Dy+3 in he solu ion we e hen analyzed using an Agilen 4100
MP-AES Spec ome e .
The adso p ion e iciency (%) o Nd+3, Tb+3, and Dy+3 by he adso ben s was compu ed
using he bellowing equa ion:
Adso p ion e iciency (%)= (𝐶0−𝐶𝑒
𝐶0)×100 (3.1)
He e Ci and C espec i ely e e o he ini ial and inal concen a ion o Nd+3, Tb+3, and Dy+3
(mg/L).
43
The adso p ion capaci y (q (mg/g)) a ime is acqui ed as bellow:
(3.2)
He e Ci and C (mg/L) espec i ely show Nd+3, Tb+3, and Dy+3 concen a ions a p ima y and
gi en ime . V (L) also e e s o he solu ion olume and M (g) shows he adso ben mass.
The equilib ium adso p ion capaci y (qe (mg/g)) was compu ed using he equa ion in he
ollowing:
(3.3)
He e Ce shows he concen a ion o Nd+3, Tb+3, and Dy+3 a equilib ium (mg/L).
3.6.1.1. pH e ec
As men ioned in sec ion 1.2, he solu ion pH a ec s he solu ion chemis y o REEs.
The e o e, he adso p ion p ocess is always pH-dependen and he capaci y o adso p ion is
changed wi h he pH o he medium. The impac o pH on adso p ion o Nd+3, Tb+3, and Dy+3
was explo ed a a ious le els o 1.5 o 5.5 by adding a gi en amoun o he adso ben s in o he
Nd+3, Tb+3, and Dy+3 solu ions a cons an ini ial concen a ion and con ac ime a oom
empe a u e.
3.6.1.2. Con ac ime e ec
The con ac ime is impo an as he possible apidness o binding and adso p ion
p ocesses o he me al ion by adso ben needs o be iden i ied o each he op imum ime o
comple e adso p ion o he me al ion (Mehdinia e al., 2015). Any change in adso p ion capaci y
by he conside a ion o con ac ime can be asc ibed o he capaci y o adso ben si es and me al
concen a ion g adien . The e ec o con ac ime was pe o med a di e en con ac imes by
adding a gi en quan i y o he adso ben in o he Nd+3, Tb+3, and Dy+3 solu ions unde con inuous
s i ing a cons an ini ial concen a ion and pH a oom empe a u e.
3.6.1.3. Adso ben dosage e ec
As he ex en o adso p ion is changed by inc easing he amoun o adso ben due o he
enhancemen in he a ailable numbe o ac i e si es o adso p ion o me al ion, he e ec o he
 
M
VCC
q i


 
M
VCC
qei
e


44
adso ben dosage on he adso p ion o Nd+3, Tb+3, and Dy+3 om aqueous solu ions was
in es iga ed by changing he dosage o he adso ben a cons an ini ial concen a ion, ime and
pH a oom empe a u e.
3.6.1.4. Ini ial concen a ion e ec
The me al ion mass ans e be ween he solid phase and aqueous is changed by he
d i ing o ce ha is a ied a any ini ial concen a ion, esul ing in adso p ion capaci y change.
To in es iga e he in luence o ini ial concen a ion on he adso p ion o he me al ions om
aqueous solu ion, he empi ical es s we e ca ied ou in he solu ions ha ing a pa icula amoun
o he adso ben wi h di e en concen a ions o Nd+3, Tb+3, and Dy+3 anging om 30 o 300
mg/L a cons an pH alue and ime a oom empe a u e.
3.6.1.5. Ionic s eng h e ec
In gene al, indus ial e luen s con ain a ious sal s a highe le els ha dec ease he
adso p ion e iciency owing o he con es wi h a ge me al ions o in ol e adso p ion si es.
NaNO3, KNO3, and NaCl a e he mos impo an ones ha ha e been applied o explo e he ionic
s eng h in luence on he me al ions adso p ion. Among all, NaNO3 can be ega ded as an e icien
and widely-used sal ha has been used by many esea che s o his goal. The e o e, he ionic
s eng h e ec on he adso p ion o Nd+3, Tb+3, and Dy+3 on o he adso ben s was s udied by a se ies
o expe imen s a a ious concen a ions o NaNO3 solu ions.
3.6.1.6. Adso p ion kine ic models
The solu e up ake a e o a sys em is gene ally desc ibed using adso p ion kine ics ha
go e ns he adso ba e up ake esidence ime a a solid-solu ion in e ace along he di usion p ocess.
I is p esumed ha no mass ans e esis ance (bo h in e nal and ex e nal) is obse ed along he
whole p ocess o he adso p ion. Consequen ly, he adso p ion kine ics can be in es iga ed using he
esidual me al ion concen a ion in he solu ion.
Th ee kine ic models including pseudo- i s -o de , pseudo-second-o de , and in a-pa icle
di usion we e u ilized o e i y he alidi y o empi ical da a ega ding Nd+3, Tb+3, and Dy+3
adso p ion on o he adso ben s as ollowing:
45
(1) Pseudo- i s -o de model (Janos e al., 2007):
q = qe (1 − exp−K1 ) (3.4)
Whe e qe (mg/g) e e s o he capaci y o adso p ion a equilib ium, q is he adso p ion capaci y a
ime , is ime, and K1 (1/min) e e s o he pseudo- i s -o de a e cons an . The applicabili y o
he model o adso p ion o Nd+3, Tb+3, and Dy+3 on o he adso ben is in es iga ed by plo ing q s
ime ‘ ’.
(2) Pseudo-second-o de model (Sma anda e al., 2010):
q = K2qe2 /1 + K2qe (3.5)
The a e cons an (K2 (g/mg min)) and he coe icien o de e mina ion a e calcula ed om he plo
o q s .
(3) In a-pa icle di usion (Youse e al., 2016):
q = Ki 0.5 + C (3.6)
He e Ki (1/min) is he pseudo- i s -o de a e cons an while C p esen s in o ma ion abou he
hickness o he bounda y laye . A highe alue o C is ela ed o he bounda y laye di usion
e ec . Ki and C a e also compu ed using he plo o q s .
E o analysis was used o op imize he expe imen al da a wi h he kine ic models. Chi-
squa e (χ2) was employed in his pape o compa ing each model's alidi y using he equa ion in
he ollowing:
χ2 = ∑(𝑞𝑒,𝑒𝑥𝑝−𝑞𝑒,𝑐𝑎𝑙)
𝑞𝑒,𝑐𝑎𝑙
𝑛
𝑖=1 2 (3.7)
He e qe,exp and qe,cal espec i ely p esen he empi ical and calcula ed adso ben capaci ies while
n ep esen s he numbe o da a poin s.
3.6.1.7. Adso p ion iso he m models
Iso he m models a e gene ally used o ep esen he ela ions be ween he amoun o
me al adso bed on o he equi alen adso p ion si es and me al concen a ion in solu ion while he
empe a u e is cons an (Papand eou e al., 2007).
In his wo k, he wo mos impo an iso he m models we e applied o speci y he
maximum adso p ion capaci y o he adso ben and i s ela ionship wi h Nd+3, Tb+3, and Dy+3
adso bed om he solu ion as ollows:
52
4.1.2. Cha ac e iza ion o he Ni0.2Zn0.2Fe2.6O4
The esul s o FE-SEM showed ha he size o nea ly sphe ical Ni0.2Zn0.2Fe2.6O4 pa icles
was less han 100 nm (Fig. 4.2A). In Fig. 4.2B, he peaks a 2θ = 18.13°, 30.07°, 35.50°, 37.08°,
43.07°, 53.95°, 56.96°, and 63.89° a e in acco dance wi h he s anda d pa e n o nickel zinc
e i e (JCPDS 08-0234) (Ni e al., 2015; Babua and Ta a chuk, 2018, Albuque que e al., 2000).
The a e age size o he nanopa icles was 27.68 nm acco ding o he Sche e equa ion a he
Full Wid h a Hal Maximum (FWHM) o he s onges e lec ion o he XRD pa e n o he
Ni0.2Zn0.2Fe2.6O4. Fig. 4.3 indica es ha he nanopa icles a e ga he ed and o ien a ed e ically
unde a magne ic ield.
Fig. 4.2. (A) FE-SEM image and (B) XRD pa e n o Ni0.2Zn0.2Fe2.6O4 nanopa ciles.

53
Fig. 4.3. O ien a ion o he Ni0.2Zn0.2Fe2.6O4 unde a magne ic ield.
4.1.3. Cha ac e iza ion o he nanocomposi es
The FE-SEM image o he CA/CMC/Ni0.2Zn0.2Fe2.6O4 in Fig. 4.4 indica es ha he
Ni0.2Zn0.2Fe2.6O4 was dis ibu ed on he biopolyme s’ su ace o embedded wi h he biopolyme s
ha con i med he e ec i e syn hesis o he magne ic nanocomposi es. Such a esul was
ob ained o he CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4 and CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4. The FE-SEM
image o he P(PTA)/Ni0.2Zn0.2Fe2.6O4 in Fig. 4.5 shows ha he Ni0.2Zn0.2Fe2.6O4 pa icles a e
also syn hesized nea ly sphe ically in he p esence o he P(PTA) in he solu ion wi h he a e age
pa icle size o 31.62 nm. Simila peaks we e ob ained in he XRD pa e n o he
P(PTA)/Ni0.2Zn0.2Fe2.6O4 in compa ison o he XRD pa e n o he Ni0.2Zn0.2Fe2.6O4. FT-IR
esul s ob ained o he nanocomposi es con i med hei success ul syn hesis in compa ison o
he FT-IR esul s o he CA, CMC, Ni0.2Zn0.2Fe2.6O4, and P(PTA).
The EDX spec a o he biopolyme nanocomposi es showed he success ul c osslinking
eac ion o sodium algina e wi h calcium as he peak o Na+ was no seen in he spec a, and he
expec ed elemen s we e seen in he EDX o he biopolyme nanocomposi es. In he case o he
P(PTA)/Ni0.2Zn0.2Fe2.6O4, he EDX spec um showed N, C, O, Ni, Zn, Fe and S peaks ha
con i med he c ea ion o he P(PTA)/Ni0.2Zn0.2Fe2.6O4.
54
Fig. 4.4. FE-SEM image o he CA/CMC/ Ni0.2Zn0.2Fe2.6O4.
Fig. 4.5. FE-SEM image o he P(PTA)/Ni0.2Zn0.2Fe2.6O4.
55
Acco ding o he ob ained esul s o VSM, he magne ic nanopa icles showed
supe pa amagne ic beha io while he a o able magne ic sa u a ion alue was abou 45.78
emu/g. Since he magne ic nanopa icles we e combined wi h o he ma e ials, lowe magne ic
sa u a ion (14.14 emu/g o he CA/CMC/Ni0.2Zn0.2Fe2.6O4, 15.28 emu/g o he
CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and 14.88 emu/g o he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4) was
ob ained o all syn hesized composi es as expec ed. The ob ained dec ease did no a ec he
sepa a ion o he nanocomposi es and hey we e easily sepa a ed by a magne ic ield as shown in
Fig. 4.6. In he case o he P(PTA)/Ni0.2Zn0.2Fe2.6O4, he magne ic sa u a ion alue (50.49 emu/g)
was close o ha ob ained o he magne ic nanopa icles, indica ing ha he magne ic sa u a ion
was no a ec ed unde he condi ion o he solu ion and in he p esence o he dissol ed P(PTA)
in he solu ion. Thus, he P(PTA)/Ni0.2Zn0.2Fe2.6O4 was he s onges magne ic adso ben in
compa ison wi h o he s.
Fig. 4.6. Pho o o magne ic sepa a ion.
Acco ding o he TGA analysis ob ained o he P(PTA), a o able he mal s abili y as
17.53% weigh loss was seen by inc easing empe a u e om RT o 330 ◦C. The weigh loss o
he P(PTA) was 61.69 % by inc easing empe a u e up o ⁓ 600 ◦C. Enhancing he empe a u e
up o 1000 ◦C caused he comple e decomposi ion o he P(PTA). By combining he P(PTA) wi h
56
he Ni0.2Zn0.2Fe2.6O4, CA, and CMC, deg ada ion empe a u e was shi ed o a highe
empe a u e. The he mal s abili y o he syn hesized p oduc s in he ange o oom empe a u e
o 1000 ◦C was in he o de o P(PTA)/Ni0.2Zn0.2Fe2.6O4 (43.21 % weigh loss) ˃
CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4 (64.1 % weigh loss) ˃ CA/CMC/Ni0.2Zn0.2Fe2.6O4 (66.8 % weigh
loss) ˃ CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 (70.65 % weigh loss).
4.2. Adso p ion o Nd+3, Tb+3, and Dy+3 om aqueous solu ion
The adso p ion o Nd+3, Tb+3, and Dy+3 om aqueous solu ion was s udied in single,
e na y, and column sys ems.
4.2.1. In es iga ion o gene al abili y o he P(PTA) o Nd+3, Tb+3, and Dy+3 adso p ion
The P(PTA) was used o he so p ion o a e ea h me als in p ima y es s. Fo his
pu pose, 0.1 g o he P(PTA) was added in o 50 mL solu ion ha ing 30 mg/L o Dy3+ a pH o
5.3, and in he ollowing he solu ion was s i ed o 14 h. The adso p ion e iciency was
app oxima ely 100 %. Simila esul o adso p ion e iciency was achie ed by adding 0.1 g o he
P(PTA) in o he mul i-me al solu ion con aining 10 mg/L o Dy+, Tb+3, and Nd+3. The esul s
con i med he adso p ion abili y o he P(PTA) o adso p ion o Nd+3, Tb+3, and Dy+3. Mo eo e ,
he p esence o py imidine and hiophene ings, hyd oxyl g oups and amide linkages in he
backbones o he P(PTA) could ac as hos s o he o ma ion and adso p ion o he complex wi h
he me al ions. Mechanism o me al adso p ion by he P(PTA) is o e ed (depic ed) in Fig. 4.7.
Fig. 4.7. Mechanism o e ed o he sepa a ion o me al ions.
57
4.2.2. Nd+3, Tb+3, and Dy+3 adso p ion in he single sys em
The adso p ion o Nd+3, Tb+3, and Dy+3 in he single sys em was s udied as a unc ion o
di e en pa ame e s including pH, con ac ime, adso ben dosage, ini ial ion concen a ion, ionic
s eng h, and empe a u e.
4.2.2.1. pH e ec on Nd+3, Tb+3, and Dy+3 adso p ion
pH is gene ally known as an essen ial con olling pa ame e along he adso p ion p ocess.
In his ega d, hyd ogen ion concen a ion ole was s udied o he adso p ion o Nd+3, Tb+3, and
Dy+3 a a ious pH, pa icula ly in he ange o 1.5 o 5.5 (1.5, 2.5, 3.5, 4.5, and 5.5) wi h a ious
p epa ed ma e ials a oom empe a u e o 25 °C by ba ch mode adso p ion s udies a 30 mg/L o
he ions wi h 0.03 g o he CA/CMC/Ni0.2Zn0.2Fe2.6O4, CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4,
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 nanocomposi es o 20 min. The expe imen s we e no s udied a
a pH highe han 5.5 because he o ma ion o he ions hyd oxides may ha e aken place
(Aghayan e al., 2013). The obse ed expe imen al esul s o he impac o pH on he ions
adso p ion om he aqueous solu ion using he adso ben s p esen ed ha he adso p ion
e iciency o he ions inc eased om 0 % o a maximum alue o all he adso ben s, o a
a ia ion o pH om pH = 1.5 o pH = 5.5 wi hin 20 min o adso p ion s udy. Based on he
ob ained esul s, i was clea ha he e was p ac ically no adso p ion a pH = 1.5 due o he
highly acidic solu ion, p e en ing he ions om u he adso p ion on o he su ace o he
adso ben s. The maximum adso p ion e iciency was achie ed a pH = 5.5 o all he adso ben s
wi h ini ial ions concen a ion o 30 mg/L, which indica ed hei maximum adso p ion e iciency
a a highe pH alue. Howe e , while he pH alue is low, elec os a ic epulsion will be high
along wi h he me al ions up ake which can be because o he high posi i e cha ge densi y and
he p o ons on he su ace ac i e si es. Mo eo e , he e is a compe i ion be ween he me al ions
and H+ ions o occupying he same si e which esul s in lowe e iciency o elimina ion. On he
o he hand, by inc easing he pH alue, elec os a ic epulsion will be educed which can be due
o he posi i e cha ge densi y educ ion on he adso p ion si es which esul s in an inc ease in he
me al ions adso p ion. Se e al ea lie s udies had also suppo ed he men ioned ac abou he
in luence o pH on adso p ion (Koochaki-Mohammadpou e al., 2014, Akkaya, 2014).
The e o e, he op imum alue o he solu ion pH was 5.5. In he case o he

58
P(PTA)/Ni0.2Zn0.2Fe2.6O4 he in luence o pH was no conduc ed and he solu ion pH o
adso p ion s udies was 5.5.
4.2.2.2. Con ac ime e ec on Nd+3, Tb+3, and Dy+3 adso p ion
Nd+3, Tb+3, and Dy+3 adso p ion e iciency also depends on hei con ac ime wi h he
adso ben s. The ions adso p ion a a ious con ac imes was in es iga ed o ini ial ions
concen a ion o 30 mg/L a pH = 5.5 keeping all o he pa ame e s cons an . Ba ch adso p ion
es s we e ca ied ou a 25 °C by changing he con ac ime om 2.5 o 70 minu es o he
CA/CMC/Ni0.2Zn0.2Fe2.6O4 and CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, 2.5 o 120 min o he
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and 2.5 o 150 min o he P(PTA)/Ni0.2Zn0.2Fe2.6O4.
Based on he ob ained esul s, mo e han 65% o adso p ion e iciency ook place wi hin
he i s 5 min o he CA/CMC/Ni0.2Zn0.2Fe2.6O4 and CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4 and
equilib iums we e espec i ely es ablished a e 40 min and 50 min. In he case o he
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, he adso p ion e iciency o mo e han 65% occu ed a he
con ac ime o 90 min. Simila esul o adso p ion e iciency was ob ained a 50 mg/L o he
ions wi h 0.13 g o he P(PTA)/Ni0.2Zn0.2Fe2.6O4 while a con ac ime o 30 min was applied. The
alue o adso p ion e iciency was ound o inc ease o mo e han 90% o he
CA/CMC/Ni0.2Zn0.2Fe2.6O4 and CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4 and 70% o he
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 by enhancing he con ac ime o he equilib ium ime.
Fo he P(PTA)/Ni0.2Zn0.2Fe2.6O4, he adso p ion e iciency was ound o inc ease o mo e
han 80% wi h a con ac ime o 130 min as equilib ium o ini ial ions concen a ion o 50 mg/L.
The change in he adso p ion e iciency a e migh e e o he ac ha all adso ben si es a e
ini ially emp y and he solu e concen a ion g adien is high. The e o e, he adso p ion a e is
high oo. The ea e , he ions up ake a e by adso ben dec eases owing o he educ ion in
adso p ion si es besides he ions concen a ion. By passing he ime, he numbe o si es on he
adso ben packed wi h he ions enhances oo (Fa ghali e al., 2013). No ably, he adso p ion a e
is equal o he deso p ion a e a equilib ium while all he si es a e packed. The e o e, i is
obse ed ha he e is no any enhancemen in adso p ion e iciency by inc easing he con ac
ime a e equilib ium. Dec eased a e o emo al, especially owa ds he end o expe imen s,
indica es he easible monolaye c ea ion o he ions on he ou e su ace o he adso ben s. In he
cu en s udy, s eady g ow h in adso p ion e iciency was seen up o a con ac ime o 40 min o
he CA/CMC/Ni0.2Zn0.2Fe2.6O4, 50 min o he CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, 90 min o he
59
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and 130 min o he P(PTA)/Ni0.2Zn0.2Fe2.6O4, while he e was
no any u he enhancemen in adso p ion e ec i eness wi h an enhancemen in ime.
4.2.2.3. Adso ben dosage e ec on Nd+3, Tb+3, and Dy+3 adso p ion
Ba ch adso p ion in es iga ions we e conduc ed a 25 °C a pH = 5.5 and he op imum
ime o each adso ben . The in luence o di e en adso ben dosage on he adso p ion e iciency
o he ions om aqueous solu ion wi h adso ben s u ilized in his wo k p esen ed ha he ions
adso p ion inc eased by enhancing he adso ben dosage o all he adso ben s. I was seen ha
he adso p ion e iciency o ions espec i ely inc eased om 53.08 o 97.75 %, 51.4 o 96.83 %,
and 59.04 o 97.88 % o Nd+3, Tb+3, and Dy+3, by using 0.01 o 0.04 g o he
CA/CMC/Ni0.2Zn0.2Fe2.6O4 and ini ial ions concen a ion o 30 mg/L. Unde he same condi ions,
he esul s we e 51.14 o 96.73 %, 49.33 o 94.82 %, and 50.66 o 97.58 % o Nd+3, Tb+3, and
Dy+3, espec i ely, by using he CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4. The adso p ion e iciency
inc eased om 26.63 o 88.24 %, 23.13 o 82.03 %, and 28.96 o 91.27 % o Nd+3, Tb+3, and
Dy+3 espec i ely, using he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 in he ange o 0.01 o 0.04 g ha
was lowe han hose o he CA/CMC/Ni0.2Zn0.2Fe2.6O4 and CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4. By
inc easing he adso ben dosage o he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 o 0.06 g, 98.15, 97.6, and
99.42 % adso p ion e iciencies we e espec i ely ob ained o Nd+3, Tb+3, and Dy+3. As o he
P(PTA)/Ni0.2Zn0.2Fe2.6O4, he ob ained esul s we e 26.34 o 95.67 %, 31.21 o 97.48 %, and
32.08 o 98.41 % o Nd+3, Tb+3, and Dy+3, espec i ely a 50 mg/L o he ions in he dosage
ange o 0.05 o 0.15 g. Such esul s we e expec ed o a cons an ini ial concen a ion o he ions
because an inc ease in adso ben dosage p o ides la ge adso p ion si es o su ace a ea which
esul s in a highe adso p ion e iciency (Das and Das, 2013). Howe e , i was seen ha a e
uppe alue o he dosage o each adso ben , he e was no any conside able modi ica ion in he
adso p ion e iciency o he ions ha migh be owing o he ac i e si es o e lapping a a highe
dosage. The e o e, he e was no any conside able enhancemen in he e icien su ace a ea
because o he adso ben pa icles conglome a ion (Pa hania e al., 2017).
4.2.2.4. Ini ial concen a ion e ec on Nd3+, Tb+3, and Dy+3 adso p ion
The ini ial me al ions concen a ion plays a signi ican ole in adso p ion due o he ac
ha only a ixed amoun o me al ions can be adso bed by he gi en mass o adso ben ma e ial.
The ini ial concen a ion o he ions solu ion was anging om 30 o 300 mg/L (excep as o he
60
adsop ion o he ions by he P(PTA)/Ni0.2Zn0.2Fe2.6O4 ha he lowe ini ial ions concen a ion
alue was 50 mg/L), and ba ch mode es s we e ca ied ou using he op imum dosage o he
adso ben s a oom empe a u e o 25 °C o explo e he impac o ini ial concen a ion o he ions
on hei adso p ion by he magne ic adso ben s. The expe imen al da a p esen ed ha he ions
adso p ion e iciency educed by enhancing he ini ial concen a ion. Adso p ion e iciencies o
he CA/CMC/Ni0.2Zn0.2Fe2.6O4 o Nd+3, Tb+3, and Dy+3 espec i ely dec eased om 97.3 o 19.4
%, 96.83 o 27.53 %, and 97.85 o 31.51 % which indica ed ha inc easing ini ial concen a ion
had mo e e ec on he adso p ion o in compa ison o Tb+3 and Dy+3. The ob ained alues o he
CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4 we e app oxima ely simila o hose o he
CA/CMC/Ni0.2Zn0.2Fe2.6O4. A he op imum dosage o he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 (0.06
g), he ob ained adso p ion e iciencies a he ini ial concen a ion o 300 mg/L we e 16.74,
21.45, and 21.76 % o Nd+3, Tb+3, and Dy+3, espec i ely, ha we e lowe han hose o
CA/CMC/Ni0.2Zn0.2Fe2.6O4 and CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4 in he in es iga ed ange o ini ial
concen a ion. The eason o he obse ed dec ease by inc easing ini ial concen a ion is due o
he ac ha he amoun o ions ha can be adso bed o a gi en mass o adso ben ma e ial is
ixed. The e o e, he highe concen a ion o he ions leads o a smalle quan i y o adso p ion
e iciency. While he concen a ion is low, he e a e la ge acan ac i e si es on he su ace o he
adso ben s and by inc easing he ini ial ions concen a ion, he numbe o ac i e si es ha a e
equi ed o adso p ion is dec eased. None heless, he eal amoun o ions adso bed pe uni mass
o adso ben enhanced by inc easing he ions concen a ion. Consequen ly, i can be due o he
high d i ing o ce o o e come he mass ans e s abili y be ween he aqueous and solid phase a
a high ini ial ions concen a ion. Ac ually, as he ini ial concen a ion o me al ions is inc eased,
he in e ac ion be ween adso ben and adso ba e also enhances (Giese and Jo dão, 2019).
Howe e , he adso p ion e iciency o he ions is maximum a lowe ini ial concen a ions.
The e o e, he p ocess o he adso p ion g ea ly elies on he ini ial concen a ion o he ions.
4.2.2.5. Adso p ion kine ics
F om i ing he da a o kine ic o he adso p ion o Nd+3, Tb+3, and Dy+3 by he
adso ben s (Tables 4.1-4.4), i was ound ha he R2 alues o he ions o he pseudo- i s -o de
model ˂ 0.91 o he CA/CMC/Ni0.2Zn0.2Fe2.6O4, ˂ 0.90 o he CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, ˂
0.89 o he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and ˂ 0.91 o he P(PTA)/Ni0.2Zn0.2Fe2.6O4 we e
61
lowe han hose acqui ed by pseudo-second-o de model (˃ 0.98 o he
CA/CMC/Ni0.2Zn0.2Fe2.6O4 and CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, ˃ 0.95 o he
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and ˃ 0.97 o he P(PTA)/Ni0.2Zn0.2Fe2.6O4, implying ha he
adso p ion o he ions was no desc ibed wi h pseudo– i s –o de model. Based on he ob ained
esul s, he calcula ed alues o adso p ion capaci y (qe,cal) o he me al ions on o he adso ben s
a equilib ium by he pseudo–second–o de we e in good comp omise wi h he expe imen al
alues (qe,exp) o adso p ion capaci ies o ions. The esul s we e also con i med by lowe alues
o χ2 ob ained by pseudo–second–o de i ing in compa ison wi h hose o he pseudo- i s -o de
model. The s abili y o he empi ical da a wi h he pseudo–second–o de kine ic model indica ed
ha he ions adso p ion on o he adso ben s was supe ised by chemical adso p ion
(chemiso p ion). The pseudo– i s –o de and pseudo–second–o de equa ions we e no able o
dis inguish he di usion me hod. The da a we e hen i ed by he in a-pa icle di usion
echnique. Based on he model, he cu e o q s. 0.5 can be linea i in a-pa icle di usion is
ela ed o he adso p ion. I he plo s go h ough he o igin, hen in a-pa icle di usion is he
a e-de e mining s ep (I ekha e al., 2018).
The da a i ing by he in a-pa icle di usion model showed a mul i-s eps adso p ion
p ocess o each me al by he CA/CMC/Ni0.2Zn0.2Fe2.6O4, CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and
P(PTA)/Ni0.2Zn0.2Fe2.6O4. The i s sha pe po ion was a ibu ed o he di usion o he ions
h ough he solu ion o he ex e nal su ace o he adso ben s (ex e nal di usion). The second
linea po ion explained he g adual adso p ion s age whe e he in a-pa icle di usion is a e-
limi ing. Finally, he hi d linea po ion deno ed he es ablishmen o he equilib ium s ep whe e
he in a-pa icle di usion s a ed o decele a e owing o he ema kably low concen a ion o he
ions in he solu ion (in apa icle di usion) (Song e al., 2013). The cu es did no go h ough he
o igin (in e cep > 0) ha migh be indica i e o some deg ee o e ec and con ol by bounda y
laye . This migh be ep esen a i e o some deg ee o bounda y laye con ol. Mo eo e , i also
in ima es ha he in a-pa icle di usion does no only con ibu e o he a e-de e mining s ep bu
also he adso p ion a e may be simul aneously con olled by o he p ocesses (Das e al., 2017).
In he case o he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, he R2 alues o 0.9737, 0.9782, and 0.9676
along wi h he χ2 alues o 1.63, 1.31, and 2.03 espec i ely ob ained by i ing wi h he in a-
pa icle di usion o Nd+3, Tb+3, and Dy+3, showed ha his model can also explain he ions
adso p ion.
68
4.2.2.7 Ionic s eng h e ec
The p esence o sal s in he solu ion can cause a dis u bance in he adso p ion pe o mance
o a ge ions wi h compe i ion o in e ac ion wi h he ac i e si es o he adso ben . In he p esen
s udy, he in luence o NaNO3 in he solu ion on he Nd+3, Tb+3, and Dy+3 adso p ion was s udied a
pH = 5.5 wi h 30 mg/L concen a ion o he ions and NaNO3 concen a ion in he ange o 0.02 o 1
M a op imum condi ions ob ained o he dosage o he adso ben s and con ac ime. I was ound
ha by inc easing he concen a ion o NaNO3, a nega i e in luence on he adso p ion e iciency o
he adso ben s was ob ained. The adso p ion e iciency o he CA/CMC/Ni0.2Zn0.2Fe2.6O4 dec eased
om 97.75 o 85.7, 96.83 o 84.73, and 97.85 o 93.5 % o Nd+3, Tb+3, and Dy+3, espec i ely. The
nega i e e ec o NaNO3 on he adso p ion he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 was app oxima ely
he same as he esul s ob ained o he CA/CMC/Ni0.2Zn0.2Fe2.6O4 wi h he alues o 98.15 o
88.39, 97.6 o 82.4, and 99.42 o 94.1 % ha we e espec i ely ob ained o Nd+3, Tb+3, and Dy+3.
The alues o adso p ion e iciency ob ained by he P(PTA)/Ni0.2Zn0.2Fe2.6O4 exp essed educ ion
om 95.67 o 67.42 o Nd+3, 97.48 o 81.7 o Tb+3, and 98.41 o 87.41 % o Dy+3, espec i ely. In
he case o he CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, he p esence o NaNO3 in he solu ion had he highes
nega i e e ec s on he adso p ion o he ions wi h he alues o 96.73 o 56.8, 94.82 o 63.23, and
97.58 o 63.96 % espec i ely ob ained o Nd+3, Tb+3, and Dy+3. The esul s migh be due o he
compe i ion o Na+ ions in he solu ion wi h he me al ions o in e ac ing wi h he ac i e si es o he
adso ben s and educ ion in he ac i i y coe icien o he me al ions ha causes he limi a ion o he
ions ans e o he adso ben su ace. Simila e ec o NaNO3 o he adso p ion o REEs using
adso ben s has been epo ed by he esea che s (Šolić e al., 2020).
4.2.2.8. Tempe a u e e ec and he e alua ion o he modynamic pa ame e s
In es iga ing he e ec o empe a u e on he ions adso p ion e iciency using he
syn hesized nanocomposi es was pe o med a di e en empe a u es o 25, 35, and 45 °C wi h
90 mg/L o me al ion solu ions a op imum condi ions o adso ben dosage and con ac ime. I
was obse ed ha he adso p ion e iciency owa ds Nd+3, Tb+3, and Dy+3 was posi i ely a ec ed
by inc easing he empe a u e (Tables 4.10-4.13).
As s a ed in sec ion 3.6.1.8, he iscosi y o me al solu ion dec eased a he highe
empe a u e which esul ed in an inc ease in he di usion o adso ba e molecules ac oss he
ex e nal bounda y laye and he in e nal po es o he adso ben pa icle. The alues o

69
he modynamic pa ame e s in Tables 4.10-4.13 show ha he alues o ΔH° we e posi i e,
con i ming he endo he mic p ocess o he ions adso p ion. The posi i e alues o ΔS° we e a
esul o an inc ease in andomness on he liquid-solid in e ace. As o ΔG°, he ob ained alues
o he CA/CMC/Ni0.2Zn0.2Fe2.6O4 and CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4 we e nega i e a all
empe a u es, indica ing ha he p ocess was na u ally spon aneous and easible while he
ob ained alues o he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 showed he spon anei y o he p ocess a
a highe empe a u e. In he case o P(PTA)/Ni0.2Zn0.2Fe2.6O4, he alues o ΔG0 we e ob ained o
be posi i e a all empe a u es in he case o Nd+3, sugges ing ha he adso p ion o Nd+3 on o
he P(PTA)/Ni0.2Zn0.2Fe2.6O4 he was non-spon aneous, while he alues ob ained o Tb+3 and
Dy+3 showed he spon anei y o he adso p ion p ocess a highe empe a u es.
Table 4.10. E ec o empe a u e on he adso p ion o he ions a 90 mg/L by he
CA/CMC/Ni0.2Zn0.2Fe2.6O4 and he modynamic pa ame e s.
Tempe a u e (ºC)
Adso p ion e iciency (%)
Nd+3
Tb+3
Dy+3
25
61.72
68.51
71.95
35
65.95
74.61
77.31
45
71.81
80.59
83.84
The modynamic
pa ame e s
Nd+3
Tb+3
Dy+3
ΔHº (kJ/mol)
19.00
26.86
29.27
ΔSº (kJ/mol K)
0.068
0.097
0.106
ΔGº (kJ/mol)
Tempe a u e (ºC)
25
35
45
Nd+3
Tb+3
Dy+3
Nd+3
Tb+3
Dy+3
Nd+3
Tb+3
Dy+3
-1.737
-2.478
-2.887
-2.263
-3.331
-3.710
-3.062
-4.353
-4.943
70
Table 4.11. E ec o empe a u e on he adso p ion o he ions a 90 mg/L by he
CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4 and he modynamic pa ame e s.
Tempe a u e (ºC)
Adso p ion e iciency (%)
Nd+3
Tb+3
Dy+3
25
61.71
66.79
69.33
35
65.10
71.78
73.90
45
69.15
77.25
79.73
The modynamic
pa ame e s
Nd+3
Tb+3
Dy+3
ΔHº (kJ/mol)
13.72
21.78
23.03
ΔSº (kJ/mol K)
0.051
0.079
0.084
ΔGº (kJ/mol)
Tempe a u e (ºC)
25
35
45
Nd+3
Tb+3
Dy+3
Nd+3
Tb+3
Dy+3
Nd+3
Tb+3
Dy+3
-1.736
-2.284
-2.574
-2.168
-2.961
-3.236
-2.725
-3.823
-4.211
Table 4.12. E ec o empe a u e on he adso p ion o he ions a 90 mg/L by he
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 and he modynamic pa ame e s.
Tempe a u e (ºC)
Adso p ion e iciency (%)
Nd+3
Tb+3
Dy+3
25
45.72
50.58
52.61
35
51.05
57.51
59.89
45
58.08
64.8
67.5
The modynamic
pa ame e s
Nd+3
Tb+3
Dy+3
ΔHº (kJ/mol)
20.66
24.40
25.97
ΔSº (kJ/mol K)
0.065
0.079
0.085
ΔGº (kJ/mol)
Tempe a u e (ºC)
25
35
45
Nd+3
Tb+3
Dy+3
Nd+3
Tb+3
Dy+3
Nd+3
Tb+3
Dy+3
0.877
0.394
0.193
0.359
-0.308
-0.559
-0.861
-1.131
-1.446
71
Table 4.13. E ec o empe a u e on he adso p ion o he ions a 90 mg/L by he
P(PTA)/Ni0.2Zn0.2Fe2.6O4 and he modynamic pa ame e s.
Tempe a u e (ºC)
Adso p ion e iciency (%)
Nd+3
Tb+3
Dy+3
25
60.22
68.83
73.94
35
63.53
71.54
77.32
45
69.16
79.41
85.34
The modynamic
pa ame e s
Nd+3
Tb+3
Dy+3
ΔHº (kJ/mol)
16.32
23.18
29.88
ΔSº (kJ/mol K)
0.048
0.074
0.098
ΔGº (kJ/mol)
Tempe a u e (ºC)
25
35
45
Nd+3
Tb+3
Dy+3
Nd+3
Tb+3
Dy+3
Nd+3
Tb+3
Dy+3
1.694
0.759
0.137
1.391
0.452
-0.328
0.770
-0.664
-1.753
4.2.2.9. Reusabili y s udies
To s udy he eusabili y o he adso ben s, he op imum dosage o each adso ben (0.04 g
o he CA/CMC/Ni0.2Zn0.2Fe2.6O4 and CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, 0.06 g o he
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and 0.15 g o he P(PTA)/Ni0.2Zn0.2Fe2.6O4) was shaken wi h 50
mL solu ion o 30 mg/L o Nd+3, Tb+3, and Dy+3 (excep o he P(PTA)/Ni0.2Zn0.2Fe2.6O4 wi h 50
mg/L o Nd+3, Tb+3, and Dy+3) on a shake a 180 pm. The pH o he solu ion was adjus ed o he
desi ed alue by adding HNO3 o NaOH solu ions. A e eaching equilib ium a he op imum
ime, he magne ized adso ben s we e sepa a ed by an ex e nal magne and he concen a ions o
he Nd+3, Tb+3, and Dy+3 in he solu ions we e measu ed. Then, he adso ben s we e washed wi h
deionized wa e o emo e he unadso bed me al ions. Fo deso p ion o he ions om he
adso ben s, 50 mL o 0.2 M HNO3 was used. The deso p ion p ocess was pe o med o 2 h. The
egene a ed adso ben was employed o adso p ion o he Nd+3, Tb+3, and Dy+3 a he op imized
condi ions. The deso p ion e iciency alues o mo e han 95, 96, and 99 % we e espec i ely
ob ained o Nd+3, Tb+3, and Dy+3 using he CA/CMC/Ni0.2Zn0.2Fe2.6O4. The deso p ion
e iciencies o he Nd+3, Tb+3, and Dy+3 we e espec i ely mo e han 89, 91, and 95 % o he
CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, mo e han 82, 84, and 88 % o he
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and 82, 86, and 90 % o he P(PTA)/Ni0.2Zn0.2Fe2.6O4. I was
obse ed ha he adso p ion e iciencies o he adso ben s we e dec eased a e he ou h cycle.
A e he ou h cycle, he dec eases in adso p ion e iciency o Nd+3, Tb+3, and Dy+3 we e
72
espec i ely mo e han 95, 94, and 95% using he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4 ha we e lowe
han hose o o he adso ben s. A e he ou h cycle o adso p ion, adso p ion e iciencies o
Nd+3, Tb+3, and Dy+3 we e educed o 91.78, 90.36, and 93.56 % using he
CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, 86.43, 84.61, and 87.52 % using he
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and 84.64, 86.37, and 88.75 % using he
P(PTA)/Ni0.2Zn0.2Fe2.6O4, which showed highe e iciency o he CA/CMC/Ni0.2Zn0.2Fe2.6O4 in
compa ison wi h o he adso ben s. The educ ion in he e iciency o adso p ion migh be due o
he chemically bonding o he ions wi h he unc ional g oups ha canno be deso bed easily,
dec ease in he unc ional g oups du ing acid ea men , and dec ease in he weigh o adso ben
du ing cycles. Ne e heless, he ob ained esul s e ealed ha he adso ben s can be po en ially
used o he adso p ion o he Nd+3, Tb+3, and Dy+3.
4.2.2.10. Compe i i e adso p ion
The op imum dosage o he adso ben s ob ained in he single sys em was used o e alua e
he adso p ion o Nd+3, Tb+3, and Dy+3 ions compe i i ely in he e na y sys em o 30 mg/L o he
ions while he a io o he ions was 1:1:1. The esul s showed ha he adso p ion e iciencies o
Nd+3, Tb+3, and Dy+3 ions educed o 28.25, 48.62, and 50.58 % using he
CA/CMC/Ni0.2Zn0.2Fe2.6O4, 22.3, 48.05, and 50.28 % using he CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4,
19.4, 37.6, and 40.9 % using he CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4, and 14.32, 32.46, and 34.64 %
using he P(PTA)/Ni0.2Zn0.2Fe2.6O4. In a mul i-componen sys em, an agonism, syne gism, and
non-in e ac ion e ec s can occu wi h alues o qmix/q0 ˂ 1, qmix/q0 ˃ 1, and qmix/q0 = 1 (Wang e
al., 2017), espec i ely, whe e qmix and q0 a e espec i ely he adso p ion capaci ies o each ion
in he mix u e and single sys ems. Resul s showed an an agonism e ec o each ion on he
adso p ion o o he ions in a mul i-componen sys em wi h he qmix/q0 alues o Nd+3, Tb+3 and
Dy+3 ha we e espec i ely 0.27, 0.5, and 0.52 using CA/CMC/Ni0.2Zn0.2Fe2.6O4, 0.23, 0.51, and
0.51 using he CA/P(PTA)/Ni0.2Zn0.2Fe2.6O4, 0.2, 0.38, and 0.41 using he
CMC/P(PTA)/Ni0.2Zn0.2Fe2.6O4. 0.15, 0.33, and 0.35 o Nd+3, Tb+3, and Dy+3 using he
P(PTA)/Ni0.2Zn0.2Fe2.6O4. EDX spec um was also eco ded o each ions loaded-adso ben s a e
he adso p ion p ocess and he ob ained esul s showed he exis ence o Nd+3, Tb+3, and Dy+3
peaks in he spec a.
73
4.2.3. Simul aneous adso p ion o Nd3+, Tb+3, and Dy+3 in he e na y sys em
Al hough all he syn hesized adso ben showed hei a o able e icacy o he adso p ion
o Nd3+, Tb+3, and Dy+3, he CA/CMC/Ni0.2Zn0.2Fe2.6O4 was ound o be mo e e icien han o he
adso ben s, acco ding o he esul s ob ained by he single adso p ion s udies. The e o e, i was
applied o s udying Nd+3, Tb+3, and Dy+3 adso p ion in a mul i-componen sys em.
Fi s , he e ec o pH on he adso p ion o Nd+3, Tb+3, and Dy+3 was in es iga ed. The
esul s we e he same as hose ob ained in he single sys em as ollowing: minimum adso p ion
e iciency a pH 1.5 due o he highly acidic solu ion and maximum adso p ion e iciency a pH
5.5 because o educ ion in H+ ions. Then, o dec ease he numbe o expe imen s, ob ain use ul
in o ma ion abou he e ec o independen pa ame e s indi idually and/o in e ac i ely ha
leads o a dec ease in expe imen al e o , and model he p ocess o Nd+3, Tb+3, and Dy+3
adso p ion by he CA/CMC/Ni0.2Zn0.2Fe2.6O4, Response Su ace Me hodology (RSM) was
applied. RSM app oach usually includes h ee s ages: design and expe imen s, esponse su ace
modeling by eg ession, and op imiza ion. By conside ing adso ben dosage, con ac ime, ini ial
concen a ion, esponse (ions adso p ion e iciency), and CCD a i e le els o -α (-2), low (-1),
cen al (0), high (+1) and +α (+2), 32 indi idual expe imen al uns we e p oposed by Design
Expe 10.0. The quad a ic polynomial model o esponse e sus he independen a iables was
p esen ed as ollows (S i as a a, 2015):
2
01 1 1 1
k k k k
i i ij i j ii i
i i j i
Y x x x x
    
   
    
  
(4.2)
Whe e Y e e s o he p edic ed esponse (adso p ion e iciency), and
0

,
i

,
ii

, and
ij

espec i ely e e o he cons an coe icien , linea coe icien , quad a ic coe icien , and
in e ac ion coe icien . No ably, xi and xj a e he independen a iables, k shows he numbe o
he independen a iables, and

is he esidual e o .
Analysis o a iance (ANOVA) was used o ob ain in o ma ion abou he adequacy o he
models by e alua ing coe icien o de e mina ion (R2), lack o i , and he Fishe es (F- alue)
alues (Ma kandeya e al., 2017). By applying quad a ic eg ession modeling be ween he
esponse and independen a iables o each me al, he equa ions ob ained o adso p ion
e iciency (%) we e as ollows:
Nd (III) adso p ion e iciency (%) = 45.421 + 1.866 X1 + 514.024 X2 – 0.571 X3 – 1.322 X4 +
0.175 X5 – 0.0043 X1X3 + 0.00312 X1X4 – 0.00255 X1X5 – 2.27 X2X1 + 1.796 X2X3 + 1.351

74
X2X4 + 0.759 X2X5 + 0.00712 X3X4 -0.00258 X3X5 + 0.00469 X4X5 – 0.0126 X12 – 1237.07 X22
– 0.000393 X32 + 0.00122 X42 – 0.00378 X52
(4.3)
Tb (III) adso p ion e iciency (%) = 51.793 + 1.663 X1 + 410.645 X2 – 0.502 X3 – 0.603 X4 +
0.24 X5 – 7.549 X1X3 + 1.073 X1X4 – 1.132 X1X5 – 2.253 X2X1 + 1.651 X2X3 + 1.185 X2X4 +
1.283 X2X5 + 0.00328 X3X4 – 0.00178 X3 X5 + 0.00243 X4X5 -0.0124 X12 -1059.01 X22 –
0.0001808 X32 + 0.000553 X42 – 0.00103X52
(4.4)
Dy (III) adso p ion e iciency (%) = 58.691 + 1.632 X1 + 405.813 X2 - 0.354 X3 – 0.778 X4 –
0.315 X5 – 0.00156 X1X3 + 0.00241X1X4 – 0.000818 X1X5 – 2.405 X2X1 + 1.486 X2X3 + 1.371
X2X4 + 1.272 X2X5 + 0.00183 X3X4 – 0.00243 X3X5 + 0.00253 X4X5 – 0.0122 X12 – 1039.17
X22 + 0.000237 X32 + 0.000437 X42 – 0.0000959 X52
(4.5)
ANOVA esul s showed R2 and Radj2 o 0.9951 and 0.9862 o Nd+3, 0.9948 and 0.9853
o Tb+3, and 0.9938 and 0.9826 o Dy+3, indica ing a good ag eemen be ween he p edic ed
and expe imen al da a. The F- alues wi h a e y low p obabili y alue o 0.0001 showed ha he
p edic ed models a e s a is ically signi ican . The ‘Adequa e p ecision’’ alues o Nd+3, Tb+3,
and Dy+3 ob ained by ANOVA we e a o able due o a alue > 4 (Sol ani e al., 2013).
Addi ionally, he coe icien o a ia ion alues (C.V. %) we e ob ained o be 2.1, 1.87, and 1.97
o Nd+3, Tb+3, and Dy+3 espec i ely, ha a e low and show he eliabili y o he modeling.
Unde he condi ions o pH = 5.5, he adso ben dosage o 0.1 g, ini ial concen a ion o 30 mg/L,
and con ac ime o 53 min we e p edic ed by RSM while he adso p ion e iciencies o Nd+3,
Tb+3, and Dy+3 we e espec i ely equal o 95.72, 96.17and 99.44 %.
4.2.3.1. Ba ch adso p ion kine ic and iso he m s udies
Using 50 mL o he solu ions a 30 mg/L o Nd+3, Tb+3, and Dy+3 ions, kine ic s udies
we e pe o med by con ac ing he ions wi h 0.09 g o he CA/CMC/Ni0.2Zn0.2Fe2.6O4 a di e en
imes. The CA/CMC/Ni0.2Zn0.2Fe2.6O4 was used a he dosage o 0.09 g con ac ing wi h 50 mL o
Nd+3, Tb+3, and Dy+3 solu ions a di e en concen a ions in he ange o 30-180 mg/L a pH = 5.5.
The esul s o kine ic s udies showed ha he main mechanism o he adso p ion o he ions is
chemiso p ion due o he highes alues o R2 (0.9927 o Nd+3, 0.9933 o Tb+3, and 0.9929 o
75
Dy+3) and lowes alues o ꭓ2 (0.045 o Nd+3, 0.043 o Tb+3, and 0.048 o Dy+3) ob ained by
PSO as compa ed wi h PFO (R2 alues o 0.9617, 0.9585, and 0.9587, and ꭓ2 alues o 0.24,
0.268, and 0.279 espec i ely o Nd+3, Tb+3, and Dy+3) and IPD (R2 alues o 0.8157, 0.8225,
and 0.8222, and ꭓ2 alues o 1.16, 1.15, and 1.20 espec i ely o Nd+3, Tb+3, and Dy+3) models.
F om he i ing esul s ob ained by he iso he m models, F eundlich iso he m showed o be mo e
sui able o he desc ip ion o he adso p ion o Nd+3, Tb+3, and Dy+3 by he
CA/CMC/Ni0.2Zn0.2Fe2.6O4 acco ding o he highe alues o R2 (0.9879, 0.9654, and 0.9633
espec i ely o Nd+3, Tb+3, and Dy+3) and lowe alues o ꭓ2 (0.159, 0.55, and 0.675 espec i ely
o Nd+3, Tb+3, and Dy+3) in compa ison wi h he Langmui model (R2 alues o 0.8773, 0.9238,
and 0.9125, and ꭓ2 alues o 1.62, 1.21, and 1.61 espec i ely o Nd+3, Tb+3, and Dy+3). In
addi ion, he alues o RL o Nd+3, Tb+3, and Dy+3 we e be ween 0 and 1 (0.007, 0.006, and
0.004 espec i ely o Nd+3, Tb+3, and Dy+3), sugges ing a o able adso p ion o Nd+3, Tb+3, and
Dy+3 by he CA/CMC/Ni0.2Zn0.2Fe2.6O4. The alues o 9, 9.26, and 9.71 ha we e ob ained o n
showed a s ong in e ac ion be ween he CA/CMC/Ni0.2Zn0.2Fe2.6O4 and he me al ions.
4.2.3.2. Ionic s eng h e ec
The esul s o ionic s eng h p esen ed a nega i e e ec o NaNO3 on he adso p ion o
Nd+3, Tb+3, and Dy+3. As o Nd+3, he nega i e e ec was g ea e han hose ob ained o Tb+3
and Dy+3. G ea e nega i e e ec o NaNO3 on he adso p ion e iciency o Nd (III) was ound in
compa ison wi h Tb (III) and Dy (III). The adso p ion e iciencies o Nd (III), Tb (III), and Dy
(III) wi hou he p esence o NaNO3 we e 92.33, 93.91, and 96.25 %. In he p esence o 0.1 M
NaNO3, adso p ion e iciencies dec eased o 77.12, 85.6, and 91.43 % espec i ely o Nd+3,
Tb+3, and Dy+3 ha migh be due o he compe i ion o sodium ions wi h Nd+3, Tb+3, and Dy+3 o
in e ac ing wi h he ac i e adso p ion si es o he adso ben and a dec ease in he adso p ion si es
o he adso ben as a esul o an inc ease in agg ega ion o he adso ben by an enhancemen in
ionic s eng h.
4.2.3.3. Tempe a u e e ec and he e alua ion o he modynamic pa ame e s
50 mL o he ions a he concen a ion o 90 mg/L was con ac ed wi h 0.09 g o he
adso ben o in es iga e he in luence o a ious empe a u es (25, 35, and 45 °C) on he
adso p ion e iciency o he ions. A posi i e e ec o empe a u e was seen o he p ocess o
76
ions adso p ion while adso p ion e iciencies inc eased om 44.31, 47.14, and 49.21 o 52.64,
55.99, and 58.42 o Nd+3, Tb+3, and Dy+3, espec i ely. The posi i e alues o ΔH° (13.9, 14.76,
and 15.45 espec i ely o Nd+3, Tb+3, and Dy+3) showed an endo he mic p ocess. The posi i e
alues o ∆G◦ a all empe a u es e ealed a non-spon aneous p ocess o he ions adso p ion a
he s udied concen a ion. ΔS° alues we e also posi i e ha indica ed an inc ease in andomness
a he in e ace o he solid–solu ion was ob ained du ing he me al ions ixa ion on he adso ben
su ace.
4.2.3.4. Reusabili y s udies
Reusabili y es o he adso ben was pe o med by he adso ben loaded wi h he ions a
he condi ions o ini ial concen a ion = 30 mg/L and pH = 5.5 wi h 0.1 g o he adso ben o 53
min. Deso p ion p ocess by 0.2 M HNO3 showed ha deso p ion e iciencies we e ˃ 93, 96, and
97 % o Nd+3, Tb+3, and Dy+3, espec i ely. Using he adso ben in ou cycles showed an
insigni ican dec ease in he adso p ion e iciency as he di e ence be ween he adso p ion
e iciency o he i s cycle and he ou h cycle which we e abou 2.54, 1.63, and 1.16 %
espec i ely o Nd+3, Tb+3, and Dy+3. This esul migh be due o he easons men ioned in
sec ion 4.2.2.9. The eusabili y o he adso ben was concluded acco ding o he ob ained esul s.
4.2.3.5. Column mode
The adso p ion o Nd+3, Tb+3, and Dy+3 was s udied using a glass column (D: 0.5 cm and
L:12 cm) packed wi h 0.3 g o he adso ben while mixed wi h 1.8 g acid-cleaned sand o
dec easing p essu e d op. Fi s , a low a e o 1 mL/min o DW p o ided by a pe is al ic pump
was passed upwa d o lushing he column o an hou . Then, a e na y solu ion o 30 mg/L o
Nd+3, Tb+3, and Dy+3 was injec ed o he column o 520 min while a ac ion collec o was used
o collec he e luen e e y 10 min. Finally, Agilen 4100 MP-AES Spec ome e was used o
de e mine he concen a ion o he ions in he e luen . The imes o b eak h ough (Ce/C0=0.05)
and exhaus ion (Ce/C0=0.95) we e ob ained o be 95 and 410 min o Nd+3, 105 and 430 min o
Tb+3, and 120 and 440 min o Dy+3. Adso p ion e iciencies o Nd+3, Tb+3, and Dy+3 we e
espec i ely 46.33, 47.07, and 49.11 % while he ob ained adso p ion capaci ies we e equal o
22.70, 24.00, and 25.54 mg/g o Nd+3, Tb+3, and Dy+3, espec i ely. Bo h Thomas and Yan
77
models we e i ed well he expe imen al da a o Nd+3, Tb+3, and Dy+3 column adso p ion. The
esul s o column adso p ion indica ed success ul p ac ical usage o he adso ben .
84
REFERENCES
 Aghayan, H., Mahjoub, A.R., Khanchi, A.R., Sama ium and dysp osium emo al using 11-
molybdo- anadophospho ic acid suppo ed on Z modi ied mesopo ous silica SBA-15,
Chemical Enginee ing Jou nal, 225 (2013) 509–519.
 Akkaya, R., Syn hesis and cha ac e iza ion o a new low-cos composi e o he adso p ion o
a e ea h ions om aqueous solu ions, Chemical Enginee ing Jou nal, 200 (2012) 186–191.
 Akkaya, R., Te bium adso p ion on o polyhyd oxye hylme hac yla e–hyd oxyapa i e
composi e and i s modi ied composi ion by phy ic acid, Desalina ion and Wa e T ea men ,
52 (2014) 1440-1447.
 Albuque que, A.S., A disson, J.D., Macedo, W.A.A., Al es, M.C.M., Nanosized powde s o
NiZn e i e: Syn hesis, s uc u e, and magne ism, Jou nal o Applied Physics, 87, 4352
(2000).
 Anas opoulos, I., Bha naga , A., Lima, E.C. Adso p ion o a e ea h me als: A e iew o
ecen li e a u e, Jou nal o Molecula Liquids, 221 (2016) 954-962.
 Ani ha, A., Di ya Rani, V.V., K ishna, R., S eeja, V., Sel amu ugan, N., Nai S.V., Tamu a
H., Jayakuma , R., Syn hesis, cha ac e iza ion, cy o oxici y and an ibac e ial s udies o
chi osan, O-ca boxyme hyl and N,O-ca boxyme hyl chi osan nanopa icles, Ca bohyd a e
Polyme s, 78 (2009) 672–677 .
 Ashou , R.M., El-Sayed, R., Abdel-Magied, A.F., Abdel-Khalek, A.A., Ali, M.M., Fo sbe g,
K., Uheida, A., Muhammed, M., Du a, J., Selec i e sepa a ion o a e ea h ions om
aqueous solu ion using unc ionalized magne i e nanopa icles: kine ic and he modynamic
s udies, Chemical Enginee ing Jou nal, 327 (2017) 286–296.
 Awual, M.R., Alha hi, N.H., Okamo o, Y., Ka im, M.R., Halim, M.E., Hasan, M.M.,
Rahman, M.M., Islam, M.M., Khaleque, M.A., Sheikh, M.C., Ligand ield e ec o
Dysp osium(III) and Lu e ium(III) adso p ion and EXAFS coo dina ion wi h no el
composi e nanoma e ials, Chemical Enginee ing Jou nal, 320 (2017) 427-435.
 Aziz H.A., Adlan M.N., A i in K.S., Hea y me als (Cd, Pb, Zn, Ni, Cu and C (III)) emo al
om wa e in Malaysia: pos ea men by high quali y limes one, Bio esou ce Technology,
99 (2008) 1578-1583.

85
 Babu, B.R., Ta a chuk, T., Elas ic p ope ies and an is uc u al modeling o Nickel-Zinc
e i e-alumina es, Ma e ials Chemis y and Physics, 207 (2018) 534-541.
 Bala am, V., Ra e ea h elemen s: A e iew o applica ions, occu ence, explo a ion,
analysis, ecycling, and en i onmen al impac , Geoscience F on ie s, 10 (2019) 1285-1303.
 Bala am, V., Recen ad ances in he de e mina ion o elemen al impu i ies in
pha maceu icals - S a us, challenges and mo ing on ie s, T ends in Analy ical Chemis y,
80 (2016) 83-95.
 Ba akos, G., An assessmen ool o he mineabili y o a e ea h elemen deposi s. Ph.D.
Diss. Technical Uni e si y Be gakademie F eibe g, Ge many, 2017.
 Ba os, Ó., Cos a, L., Cos a, F., Lago, A., Rocha, V., Vipo nik, Z., Sil a, B., Ta a es, T.,
Reco e y o a e ea h elemen s om was ewa e owa ds a ci cula economy, Molecules, 24
(2019) 1005.
 Baybaş, D., Ulusoy, U., Polyac ylamide–clinop iloli e/Y-zeoli e composi es:
Cha ac e iza ion and adso p i e ea u es o e bium, Jou nal o Haza dous Ma e ials, 187
(2011) 241–249.
 Bhushan, B., Handbook o Nano echnology, publishe Sp inge , (2010) 1-5.
 Binnemans, K., Tom Jones, P., Blanpain B., Van Ge en, T., Yang, Yongxiang., Wal on
Allan., Buche , M., Recycling o a e ea hs: a c i ical e iew, Jou nal o Cleane
P oduc ion, 51 (2013) 1-22.
 B accini, I., Pé ez S., Molecula basis o Ca2+-induced gela ion in algina es and pec ins:  he
egg-box model e isi ed, Biomac omolecules, 2 (2001) 1089-1096.
 B ookins, D.G., Aqueous geochemis y o a e ea h elemen s. Geochemis y and Mine alogy
o Ra e Ea h Elemen s, B.R. Lipin and G.A. McKay, eds. Washing on, DC, The
Mine alogical Socie y o Ame ica, 21 (1989) 201-212.
 B zyska, W., Lan hanides and Ac inides, Wydawnic wa Naukowo-Techniczne Poland,
(1996) 40-41.
 Chakhmou adlan, A.R., Wall, F., Ra e ea h elemen s: Mine als, mines, magne s (and mo e),
Elemen s, 8 (2012) 333–340.
 Cha opadhyay, K.K., Bane jee, A.N., In oduc ion o nanoscience and nano echnology,
Publishe PHI lea nings p l d, Chap 1 (2009) 1-5.
86
 Chen, W., Honghui, H., Bai, T., Jiang, S., Geochemis y o monazi e wi hin ca bona i e
ela ed REE deposi s, Resou ces, 6 (2017) 51.
 Chen, X.G., Pa k, H.J., Chemical cha ac e is ics o O-ca boxyme hyl chi osans ela ed o he
p epa a ion condi ions, Ca bohyd a e Polyme s, 53 (2003) 355-359.
 Chu, L., Yan, S., Xing, X.H., Sun, X., Ju cik, B., P og ess and pe spec i es o sludge
ozona ion as a powe ul p e ea men me hod o minimiza ion o excess sludge p oduc ion,
Wa e Resea ch, 43 (2009) 1811-1822.
 Das, N., Das, D., Reco e y o a e ea h me als h ough bioso p ion: An o e iew, Jou nal o
Ra e Ea hs, 31 (2013) 933-943.
 Das, R., Gi i, S., Muliwa, A.M., Mai y, A., High-pe o mance Hg(II) emo al using hiol-
unc ionalized polypy ole (PPy/MAA) composi e and e ec i e ca aly ic ac i i y o Hg(II)-
adso bed was e ma e ial, ACS Sus ainable Chemis y & Enginee ing, 5 (2017) 7524-7536.
 de Ab eu, F.R., Campana-Filho, S.P., Cha ac e is ics and p ope ies o ca boxyme hyl
chi osan, Ca bohyd a e Polyme s, 75 (2009) 214-221.
 Dos al, J., Ra e ea h elemen deposi s o alkaline igneous ocks, Resou ces, 6 (2017) 34.
 Dou, J., Liu, Z., A simple and e icien syn he ic me hod o poly(e hylene e eph hala e):
phenylalkyl py olidinium ionic liquid as polycondensa ion medium, G een Chemis y, 14
(2012) 2305-2313.
 Dupon , D., B ullo W., Bloemen, M., Ve bies , T., Binnemans, K., Selec i e up ake o a e
ea hs om aqueous solu ions by EDTA- unc ionalized magne ic and Nonmagne ic
nanopa icles, ACS Applied Ma e ials & In e aces, 6 (2014a) 4980−4988.
 Dupon , Da id., Luy en, J., Bloemen, M., Ve bies , T., Binnemans, K., Acid-s able magne ic
co e−shell nanopa icles o he sepa a ion o a e ea hs, Indus ial & Enginee ing
Chemis y Resea ch, 53 (2014b) 15222−15229.
 Esma , M., Fa ghali, A.A., Khed , M.H., El-She biny I.M., Algina e-based nanocomposi es
o e icien emo al o hea y me al ions, In e na ional Jou nal o Biological
Mac omolecules, 102 (2017) 272-283.
 Esse , B.K., Volpe, A., Kenneally, J.M., Smi h, D.K., P econcen a ion and pu i ica ion o
a e ea h elemen s in na u al wa e s using silica-immobilized 8-hyd oxyquinoline and a
suppo ed o ganophospho us ex ac an , Analy ical Chemis y, 66 (1994) 1736-1742.
87
 Eu opean Commission C i ical aw ma e ials o he EU, Repo o he Ad-hoc Wo king
G oup on de ining c i ical aw ma e ials, h p://ec.eu opa.eu/en e p ise/policies/ aw-
ma e ials/c i ical/index_en.h m.
 E ans, E.1., Fellows, J., Co e , A., Wood, R.D., Open complex o ma ion a ound a lesion
du ing nucleo ide excision epai p o ides a s uc u e o clea age by human XPG
p o ein, The EMBO Jou nal, 16 (1997) 625-638.
 Fagundes-Klen M.R., Fe i, P., Ma ins, T.D., Ta a es, C.R.G., Sil a, E.A., Equilib ium
s udy o he bina y mix u e o cadmium–zinc ions bioso p ion by he Sa gassum ilipendula
species using adso p ion iso he ms models and neu al ne wo k, Biochemical Enginee ing
Jou nal, 34 (2007) 136-146.
 Fa ghali, A.A., Bahga , M., Allah, A.E., Khed , M.H., Adso p ion o Pb(II) ions om
aqueous solu ions using coppe oxide nanos uc u es, Beni-Sue Uni e si y Jou nal o Basic
and Applied Sciences, 2 (2013) 61-71.
 Fe on, C.J., Bula o ic, S.M., Sal e , R.S., Bene icia ion o a e ea h oxide mine als.
Ma e ials Science Fo um. T ans Tech Publica ions, Swi ze land, (1991).
 Fise , J.F, Blais, J.F, Ri e os, P.A., Re iew on he emo al o me al ions om e luen s using
seaweeds, algina e de i a i es and o he so ben s, Jou nal o Wa e Science, 21 (2008) 283-
308.
 Flo ek, J., Chali ou , F., Bilodeau, F., La i iè e, D., Klei z, F., Nanos uc u ed hyb id
ma e ials o he selec i e eco e y and en ichmen o a e ea h elemen s, Ad anced
Func ional Ma e ials, 24 (2014) 2668-2676.
 Gabo , A.E. Da idescu, C.M., Neg ea, A., Ciopec, M., Bu na iu, M., Ianasi, C., Mun ean, C.,
Neg ea, P., Lan hanum sepa a ion om aqueous solu ions using magnesium silica e
unc ionalized wi h e abu ylammonium dihyd ogen phospha e, Jou nal o Chemical &
Enginee ing Da a, 61 )2016 ( 535−542.
 Gambogi, J., 2016. Ra e Ea hs. U.S. Geological Su ey. Mine al Commodi y Summa ies.
 Gambogi, J., Ra e Ea hs, Uni ed S a es Geological Su ey, Mine al Commodi y Summa ies,
(2017).
 Gambogi, J., Ra e Ea hs, Uni ed S a es Geological Su ey, Mine als Yea book, (2011).
 Gambogi, J., Ra e Ea hs. USGS Geological Su ey, Mine al Commodi y Summa ies,
USGS, Res on, VA, 2013.
88
 Ganguli, R., Cook, D.R., Ra e ea hs: A e iew o he landscape, MRS Ene gy &
Sus ainabili y, (2018).
 Gao, Z., Bandosz, T.J., Zhao, Z., Han, M., Qiu, J., In es iga ion o ac o s a ec ing
adso p ion o ansi ion me als on oxidized ca bon nano ubes, Jou nal o Haza dous
Ma e ials, 167 (2009) 357–365.
 Ga cía, JM., Ga cía, F.C., Se na, F., de la Peña, J.L., High-pe o mance a oma ic
polyamides, P og ess in Polyme Science, 35 (2010) 623–686.
 Giese, E.C., Jo dão, C.S., Bioso p ion o lan hanum and sama ium by chemically modi ied
ee Bacillus sub ilis cells, Applied Wa e Science, 9 (2019) 182.
 Gomez-Valdemo o, A., San-Jose, N., Clemen e Ga cia, F., De La Pena, J.L., Se na, F.,
Miguel Ga cia, J., No el a oma ic polyamides wi h main chain and pendan 1,2,4- iazole
moie ies and hei applica ion o he ex ac ion/elimina ion o me cu y ca ions om aqueous
media, Polyme Chemis y, 1 (2010) 1291–1301.
 Go oh, T., Ma sushima, K., Kikuchi, K.I., Adso p ion o Cu and Mn on co alen ly c oss-
linked algina e gel beads, Chemosphe e, 55 (2004) 57-64.
 G ebne a, O.N., Kuz'min, N.M., Tsysin, G.I., Zolo o , Y.A., On-line-so p ion
p econcen a ion and induc i ely coupled plasma a omic emission spec ome y
de e mina ion o a e ea h elemen s, Spec ochimica Ac a Pa B: A omic Spec oscopy, 51
(1996) 1417-1423.
 Guibal, E., In e ac ions o me al ions wi h chi osan-based so ben s: a e iew, Sepe a ion and
Pu i ica ion Technology, 38 (2004) 43-74.
 Gup a, C.K., K ishnamu hy, Ex ac i e me allu gy o a e ea hs, CRC P ess, (2004).
 Hadji o i, L., Cha alambous, S., Pashalidis, I., Remo al o i alen sama ium om aqueous
solu ions by ac i a ed biocha de i ed om cac us ib es, Jou nal o Ra e Ea hs, 34 (2016)
99–104.
 Hanbali, M., Holail, H., Hammud, H., Remedia ion o lead by p e ea ed ed algae:
adso p ion iso he m, kine ic, column modeling and simula ion s udies, G een Chemis y
Le e s and Re iews, 7 (2014) 342–358.
 Ha ch, G.P., Dynamics in he global ma ke o a e ea hs. Elemen s, 8(5) (2012) 341-346.
 Hea le, JW., High-pe o mance ib es, Woodhead Publishing L d, Camb idge, England
(2001).
89
 Hed ick, J.B., Ra e ea hs, Us. geological su ey mine als yea book, (2004).
 Hende son, P., The a e ea h elemen s: in oduc ion and e iew. In: Jones, A.P., Wall, F.,
Williams, C.T. (Eds.) Ra e ea h mine als: Chemis y, o igin and o e deposi s. Chapman &
Hall, London, (1996) 1–19.
 Ho nyak, L., Tibbals, H.F., Du a, J., Moo e, J.J., In oduc ion o nanoscience and
nano echnology Taylo and F ancis CRC P ess ISBN: 978-1-4200-4779-0.
 Ho s all J , M., Spi , A.I., Adso p ion o ansi ion me als in aqueous solu ions by lu ed
pumpkin (Tel ai ia occiden alis Hook ) was e, Chemis y & Biodi e si y, 2 (2005).
 H is o ski, K.D., Wes e ho , P.K., C i enden, J.C., Olson, L.W., A sena e emo al by
nanos uc u ed Z O2 sphe es, En i onmen al Science & Technology, 42 (2008) 3786-3790.
 Humph ies, M., Ra e Ea h Elemen s: The Global Supply Chain, CRS Repo o Cong ess,
R41347 (www.c s.go ), 2012.
 Ibáñez, J.P., Ume su, Y., Up ake o i alen ch omium om aqueous solu ions using
p o ona ed d y algina e beads, Hyd ome allu gy, 72 (2004) 327-334.
 I ekha , S., S i as a a, V., Casas, A., Sillanpää, M., Syn hesis o no el GA-g-PAM/SiO2
nanocomposi e o he eco e y o a e ea h elemen s (REE) ions om aqueous solu ion,
Jou nal o Cleane P oduc ion, 170 (2018a) 251-259.
 I ekha , S., S i as a a, V., Hammouda, S.B., Sillanpää, M., Fab ica ion o no el me al ion
imp in ed xan han gum-laye ed double hyd oxide nanocomposi e o adso p ion o a e ea h
elemen s, Ca bohyd a e Polyme s, 194 (2018b) 274-284.
 Jalali, M., Mo adi, F., Compe i i e so p ion o Cd, Cu, Mn, Ni, Pb and Zn in pollu ed and
unpollu ed calca eous soils, En i onmen al Moni o ing and Assessmen , 185 (2013) 8831–
8846.
 Janos, P., Sypecka, J., Mlcko ska, P., Ku an, P., Pila o a, V., Remo al o me al ions om
aqueous solu ions by so p ion on o un ea ed low- ank coal (oxihumoli e), Sepa a ion and
Pu i ica ion Technology, 53 (2007) 322-329.
 Jegadeesan, G., Al-Abed, S.R., Sunda am, V., Choi, H., Scheckel, K.G., Dionysiou, D.D.,
A senic so p ion on TiO2 nanopa icles: size and c ys allini y e ec s, Wa e Resea ch, 44
(2010) 965-973.

90
 Johansson, N., K ook, J., Eklund, M., Be glund, B., An in eg a ed e iew o concep s and
ini ia i es o mining he echnosphe e: owa ds a new axonomy, Jou nal o Cleane
P oduc ion, 55 (2013) 35-44.
 Kaneko, T., Naga a, F., Kugimiya, S., Ka o, K., Op imiza ion o ca boxyl- unc ionalized
mesopo ous silica o he selec i e adso p ion o dysp osium, Jou nal o En i onmen al
Chemical Enginee ing, 6 (2018) 5990-5998.
 Kegl, T., Ban, I., Lobnik, A., Košak, A., Syn hesis and cha ac e iza ion o no el γ-Fe2O3-
NH4OH@SiO2(APTMS) nanopa icles o dysp osium adso p ion, Jou nal o Haza dous
Ma e ials, 378 (2019) 120764.
 Koe h-Bake , M., 4 a e ea h elemen s ha will only ge mo e impo an , (2012).
 Koochaki-Mohammadpou , S.M.A., To ab-Mos aedi, M., Talebizadeh-Ra sanjani, A.,
Nade i-Behdani, F., Adso p ion iso he m, kine ic, he modynamic, and deso p ion s udies o
lan hanum and dysp osium on oxidized mul iwalled ca bon nano ubes. Jou nal o Dispe sion
Science and Technology, 35 (2014) 244−254.
 Lee, Y.R., Yu, K., Ra i, S., Ahn, W.S., Selec i e adso p ion o a e ea h elemen s o e
unc ionalized C -MIL-101, ACS Applied Ma e ials & In e aces, 10 (2018) 23918-23927.
 Li, H., XIAO, D., HE, H., Lin, R.; Zuo, P.; Adso p ion beha io and adso p ion mechanism
o Cu(II) ions on amino- unc ionalized magne ic nanopa icles, The T ansac ions o
Non e ous Me als Socie y o China, 23 (2013) 2657−2665.
 Liang, P., Hu, B., Jiang, Z., Qin, Y., Peng, T., Nanome e -sized i anium dioxide mic o-
column on-line p econcen a ion o La, Y, Yb, Eu, Dy and hei de e mina ion by induc i ely
coupled plasma a omic emission spec ome y, Jou nal o Analy ical A omic Spec ome y,
16 (2001) 863-866.
 Lim, A.P., A is A.Z., Con inuous ixed-bed column s udy and adso p ion modeling: Remo al
o cadmium (II) and lead (II) ions in aqueous solu ion by dead calca eous skele ons,
Biochemical Enginee ing Jou nal, 87 (2014) 50-61.
 Lin C.C., Lin, C.W., P epa a ion o N,O-ca boxyme hyl chi osan nanopa icles as an insulin
ca ie , D ug Deli e y, 16 (2009) 458–464.
 Liou, GS., Hsiao, SH., Ishida, M., Kakimo o, M., Imai, Y., Syn hesis and cha ac e iza ion o
no el soluble iphenylamine-con aining a oma ic polyamides based on N,N’-bis(4-
91
aminophenyl)-N,N’-diphenyl-1,4-phenylenediamine, Jou nal o Polyme Science Pa A:
Polyme Chemis y, 40 (2002) 2810−2818.
 Liu, E., Zheng, X., Xu, X., Zhang, F., Liu, E., Wang, Y., Li, C., Yan, Y., P epa a ion o
die hylene iamine-modi ied magne ic chi osan nanopa icles o adso p ion o a e-ea h
me al ions, New Jou nal o Chemis y, 41 (2017) 7739-7750.
 Long, K.R., Van Gosen, B.S., Foley, N.K., Co die , D., The p incipal a e ea h elemen s
deposi s o he Uni ed S a es—A summa y o domes ic deposi s and a global pe spec i e:
U.S. Geological Su ey Scien i ic In es iga ions Repo , 2010–5220, 96 p.
 Lucas, J., Lucas, P., Le Me cie , T., Rolla , A., Da enpo , W., Ra e ea hs: Science,
echnology, p oduc ion and use, Else ie Inc, (2014).
 Ma, Wei., Ya, F.Q., Han, M., Wang, R., Cha ac e is ics o equilib ium, kine ics s udies o
adso p ion o luo ide on magne ic-chi osan pa icle, Jou nal o Haza dous Ma e ials, 143
(2007) 296-302.
 Madbouly, H.A., El-He ny, N.E., El-Nadi, Y.A., Adso p ion and sepa a ion o e bium(III)
and gadolinium(III) om aqueous ni a e medium using solid ex ac an , Sepa a ion Science
and Technology, (2019) 1-13.
 Manchen, N.A., Sp eche , B., Bailey, G., Ge, J., Tukke , A., E ec o Chinese policies on
a e ea h supply chain esilience, Resou ces, Conse a ion & Recycling, 142 (2019) 101–
112.
 Manche i, N.A., Wo ld ade in a e ea hs, Chinese expo es ic ions, and implica ions,
Resou ce Policy, 46 (2015) 262-271.
 Mansoo i, Y., Mohsenzadeh, R., Designed polyamides based on 1,4-bis[(4-aminophenyl)-
1,3,4-oxadiazolyl]phenylene (BAPO) o emo al o Cu(II) and Co(II), Designed Monome s
and Polyme s, 18 (2015) 1-10.
 Mansu , H.S., Mansu , A.A.P., Cu i, E., De Almeida, M.V., Func ionalized chi osan/
quan um do s nano-hyb ids o nanomedicine applica ions: owa ds biolabeling and
bioso bing phospha e me aboli es, Jou nal o Ma e ials Chemis y B, 1 (2013) 1696-1711.
 Ma kandeya, Dhiman, N., Shukla, S.P., Kisku, G.C., S a is ical op imiza ion o p ocess
pa ame e s o emo al o dyes om was ewa e on chi osan cenosphe es nanocomposi e
using esponse su ace me hodology, Jou nal o Cleane P oduc ion, 149 (2017) 597-606.
92
 Ma mie , N., Delise´e, J.A., F omage, F., Su ace complexa ion modeling o Yb(III) and
Cs(I) so p ion on silica, Jou nal o Colloid and In e ace Science, 212 (1999) 228–233.
 Ma mie , N., Dumonceau, A.J., F omage, F., Su ace complexa ion modeling o Yb(III)
so p ion and deso p ion on hema i e and alumina, Jou nal o Con aminan Hyd ology, 26
(1997) 159–167.
 McLeod, C.L., Shaulis, B.J., Ra e ea h elemen s in plane a y c us s: Insigh s om
chemically e ol ed igneous sui es on ea h and he moon, Mine als, 8 )2018( 455.
 Mehdinia, A., Shege i, S., Shemi ani, F., Remo al o Lead(II), Coppe (II) and Zinc(II) ions
om aqueous solu ions using magne ic amine- unc ionalized mesopo ous silica
nanocomposi es, Jou nal o he B azilian Chemical Socie y, 26 (2015) 2249-2257.
 Melnyk, I.V., Goncha yk, V.P., Kozha a, L.I., Yu chenko, G.R., Ma ko sky, A.K., Zub,
Y.L., Alonso, B., So p ion p ope ies o po ous sp ay-d ied mic osphe es unc ionalized by
phosphonic acid g oups, Mic opo ous and Mesopo ous Ma e ials, 153 (2012) 171–177.
 MEP (Minis y o En i onmen al P o ec ion). Pollu an discha ge s anda ds o he Ra e
Ea h Indus y (in Chinese), (2011a).
 Meye , L., B as, B., Ra e ea h me al ecycling. Sus ainable Sys ems and Technology, (2011)
IEEE In e na ional Symposium, 16-18 May, Chicago Il.
 Mondal N.K., Ka , S., Po en iali y o banana peel o emo al o Congo ed dye om
aqueous solu ion: iso he m, kine ics and he modynamics s udies, Applied Wa e Science, 8
(2018) 157.
 Mu y, D.S.R., Chak apani, G., P econcen a ion o a e ea h elemen s on ac i a ed ca bon
and i s applica ion o g oundwa e and sea-wa e analysis, Jou nal o Analy ical A omic
Spec ome y, 11 (1996) 815- 820.
 Nase , A., El-deen, G.S., Bh an, A.A., Me wally, S., El-Kamash, A., Elabo a ion o
imp egna ed composi e o so p ion o eu opiumand neodymium ions om aqueous
solu ions, Jou nal o Indus ial and Enginee ing Chemis y, 32 (2015) 264–272.
 Nayak, D., Lahi i, S., Bioso p ion o oxic, hea y, no-ca ie -added adionuclides by calcium
algina e beads, Jou nal o Radioanaly ical and Nuclea Chemis y, 267 (2005) 59–65.
 Ng, J.C.Y., Cheung, W.H., McKay, G., Equilib ium s udies o he so p ion o lead om
e luen s using chi osan, Chemosphe e, 52 (2003) 1021-1030.
93
 Ng, J.C.Y., Cheung, W.H., McKay, G., Equilib ium s udies o he so p ion o Cu(II) ions
on o chi osan, Jou nal o Colloid and In e ace Science, 255 (2002) 64-74.
 Ni, D., Lin, Z., Xiaoling, P., Xinqing, W., Hongliang, G., P epa a ion and cha ac e iza ion o
nickel-zinc e i es by a sol o he mal me hod, Ra e Me al Ma e ials and Enginee ing, 44
(2015) 2126-2131.
 Ni, Y., Hughes, J.M., Ma iano, A.N., C ys al chemis y o he monazi e and xeno ime
s uc u es, Ame ican Mine alogis , 80 (1995) 21-26.
 Nobaha , S., Pa ini, M., Eisazadeh, H., Remo al o coppe ions om aqueous solu ions
using polypy ole and i s Nanocomposi es, Jou nal o Hea and Mass T ans e Resea ch, 1
(2014) 101-106.
 Oga a, T., Na i a, H., Tanaka, M., Rapid and selec i e eco e y o hea y a e ea hs by using
an adso ben wi h diglycol amic acid g oup, Hyd ome allu gy, 155 (2015) 105-109.
 Oli ei a, D., In e no, C., Classi ica ion o a e ea h deposi and occu ence ypes: wha ’s
new?, Comunicações Geológicas, 101 (2014) 821-823.
 Oli ei a, R.C., Jouannin, C., Guibal, E., Ga cia J , O., Sama ium(III) and p aseodymium(III)
bioso p ion on Sa gassum sp.: Ba ch s udy. P ocess Biochemis y, 46 (3) (2011) 736–744.
 O ha, C., Manea, F., Ra iu, C., Bu ica, G., Io i, A., Ob aining and cha ac e iza ion o
omanian zeoli e suppo ing sil e ions, En i onmen al Enginee ing and Managemen
Jou nal, 6 (2007) 541-544.
 Pan, B.J., Pan, B.C., Zhang, W.M., L , L., Zhang, Q.X., Zheng, S.R., De elopmen o
polyme ic and polyme -based hyb id adso ben s o pollu an s emo al om wa e s,
Chemical enginee ing Jou nal, 151 (2009) 19–29.
 Papand eou, A., S ou na as, C., Panias, D., Coppe and cadmium adso p ion on pelle s made
om i ed coal ly ash, Jou nal o Haza dous Ma e ials, 148 (2007) 538-547.
 Pa hania, D., Sha ma S., Singh P., Remo al o me hylene blue by adso p ion on o ac i a ed
ca bon de eloped om Ficus ca ica bas , A abian Jou nal o Chemis y, 10 (2017) S1445-
S1451.
 Pa a, A.K., Du a, A., Bhaumik, A., Sel -assembled mesopo ous g-Al2O3 sphe ical
nanopa icles and hei e iciency o he emo al o a senic om wa e . Jou nal o
Haza dous Ma e ials, 201-202 (2012) 170-177.
100
 Zhang, M., Zhang, Y., Helleu , Robe ., Selec i e adso p ion o Ag+ by ion-imp in ed O-
ca boxyme hyl chi osan beads g a ed wi h hiou ea–glu a aldehyde, Chemical Enginee ing
Jou nal, 264 (2015) 56–65.
 Zhao, F., Repo E., Meng, Y., Wang, X., Yin, D., Sillanpää, M., An EDTA-β-cyclodex in
ma e ial o he adso p ion o a e ea h elemen s and i s applica ion in p econcen a ion o
a e ea h elemen s in seawa e , Jou nal o Colloid and In e ace Science, 465 (2016) 215–
224.
 Zhao, Z., Sun, X., Dong, Y., Wang, Y., Syne gis ic e ec o acid–base coupling bi unc ional
ionic liquids in imp egna ed esin o a e ea h adso p ion, ACS Sus ainable Chemis y &
Enginee ing, 4 (2) (2016) 616–624.
 Zheng, X., Liu, E., Zhang, F., Yan, Y., Pan, J., E icien adso p ion and sepa a ion o
dysp osium om NdFeB magne s in an acidic sys em by ion imp in ed mesopo ous silica
sealed in a dialysis bag, G een Chemis y, 18 (2016) 5031–5040.
 Zheng, X., Zhang, Y., Bian, T., Zhang, Y., Li, Z., Pan, J., Oxidized ca bon ma e ials
coope a i e cons uc ionic imp in ed cellulose nanoc ys als ilms o e icien adso p ion o
Dy(III), Chemical Enginee ing Jou nal, 381 (2020) 122669.
 Zhou, B., Li, Z., Chen, C., Global po en ial o a e ea h esou ces and a e ea h demand
om clean echnologies, Mine als, 7 (2017) 203.
 Zhou, B., Li, Z., Zhao, Y., Zhang, C., Wei, Y., Ra e ea h elemen s supply s. clean ene gy
echnologies: New p oblems o be sol e, Gospoda ka Su owcami Mine alnymi, 32 (2016)
29–44.
 Zhu Y., Zheng, Y., Wang, A., A simple app oach o ab ica e g anula adso ben o
adso p ion o a e elemen s, In e na ional jou nal o biological mac omolecules, 72 (2015)
410-420.
 Zhu, Y., Zheng, Y., Wang, A., A simple app oach o ab ica e g anula adso ben o
adso p ion o a e elemen s, In e na ional Jou nal o Biological Mac omolecules, 72 (2015)
410-420.

101
102
LIST OF PUBLICATIONS
 Hamed eza Ja adian, Mon se a Ruiz, Taw ik A. Saleh, Ana Ma ia Sas e, Ca-
algina e/ca boxyme hyl chi osan/Ni0.2Zn0.2Fe2.6O4 magne ic bionanocomposi e: Syn hesis,
cha ac e iza ion and applica ion o single adso p ion o Nd+3, Tb+3, and Dy+3 a e ea h
elemen s om aqueous media, Jou nal o Molecula Liquids, 306 (2020) 112760.
h ps://doi.o g/10.1016/j.molliq.2020.112760
 Hamed eza Ja adian, Mon se a Ruiz, Ana Ma ia Sas e, Response su ace me hodology
based on cen al composi e design o simul aneous adso p ion o a e ea h elemen s using
nanopo ous calcium algina e/ca boxyme hyl chi osan mic obiocomposi e powde con aining
Ni0.2Zn0.2Fe2.6O4 magne ic nanopa icles: Ba ch and column s udies, In e na ional Jou nal o
Biological Mac omolecules, 154 (2020) 937-953.
h ps://doi.o g/10.1016/j.ijbiomac.2020.03.131
 Hamed eza Ja adian, Mon se a Ruiz, Mehdi Tagha i, Ana Ma ia Sas e, Syn hesis o
magne ic CMC bionanocomposi e con aining a no el biodeg adable nanopo ous polyamide
selec i ely syn hesized in ionic liquid as g een media: In es iga ion on Nd+3, Tb+3, and Dy+3
a e ea hs adso p ion, Jou nal o Molecula Liquids, 308 (2020) 113017.
h ps://doi.o g/10.1016/j.molliq.2020.113017
 Hamed eza Ja adian, Mon se a Ruiz, Mehdi Tagha i, Ana Ma ia Sas e, Syn hesis o
calcium algina e/no el selec i ely syn hesized biodeg adable poly(py imidine- hiophene-
amide) wi h ee hyd oxyl g oups in ionic liquid as g een media /Ni0.2Zn0.2Fe2.6O4 magne ic
bionanocomposi e powde : Adso p ion p ope ies owa ds a e ea h elemen s, Unde Re iew
in Mic ochemical Jou nal.
 Hamed eza Ja adian, Mon se a Ruiz, Mehdi Tagha i, Ana Ma ia Sas e, One-s ep
hyd o he mal syn hesis o g een syn hesized poly(py imidine- hiophene-amide) as no el
polyamide in imidazolium based ionic liquid as g een media/Ni0.2Zn0.2Fe2.6O4
nanocomposi e: In es iga ion on Nd+3, Tb+3, and Dy+3 adso p ion, Unde Re iew in Applied
O ganome allic Chemis y.
103
104
ANNEX I
Ca-algina e/ca boxyme hyl chi osan/Ni0.2Zn0.2Fe2.6O4 magne ic bionanocomposi e:
Syn hesis, cha ac e iza ion and applica ion o single adso p ion o Nd+3, Tb+3, and Dy+3 a e
ea h elemen s om aqueous media.
Hamed eza Ja adian, Mon se a Ruiz, Taw ik A. Saleh, Ana Ma ia Sas e.
Jou nal o Molecula Liquids, 306 (2020) 112760.
h ps://doi.o g/10.1016/j.molliq.2020.112760
105

Ca-algina e/ca boxyme hyl chi osan/Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic
bionanocomposi e: Syn hesis, cha ac e iza ion and applica ion o single
adso p ion o Nd
+3
,Tb
+3
,andDy
+3
a e ea h elemen s om
aqueous media
Hamed eza Ja adian
a,
⁎, Mon se a Ruiz
b
,TawfikA.Saleh
c,
⁎, Ana Ma ia Sas e
a
a
Depa men o Chemical Enginee ing, ETSEIB, Uni e si a Poli ècnica de Ca alunya, Diagonal 647, 08028 Ba celona, Spain
b
Depa men o Chemical Enginee ing, EPSEVG, Uni e si a Poli ècnica de Ca alunya, A . Víc o Balague , s/n, 08800 Vilano a i la Gel ú, Spain
c
Chemis y Depa men , King Fahd Uni e si y o Pe oleum and Mine als, Dhah an 31261, Saudi A abia
abs ac a icle in o
A icle his o y:
Recei ed 22 No embe 2019
Recei ed in e ised o m 18 Feb ua y 2020
Accep ed 20 Feb ua y 2020
A ailable online 21 Feb ua y 2020
Keywo ds:
Ca boxyme hyl chi osan
Calcium algina e
Ni
0.2
Zn
0.2
Fe
2.6
O
4
Adso p ion
Ra e ea h elemen s
This s udy aims o esea ch he adso p ion o Nd
+3
,Tb
+3
,andDy
+3
om aqueous media on o he magne ic cal-
cium algina e/ca boxyme hyl chi osan/Ni
0.2
Zn
0.2
Fe
2.6
O
4
(CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
) bionanocomposi e in a sin-
gle sys em. FE-SEM, FT-IR, EDX, VSM, and TGA we e applied o cha ac e ize he p oduc . The VSM esul
showed hesa u a ionmagne iza ion alueso 45.87 and14.14 emu/g o heba eNi
0.2
Zn
0.2
Fe
2.6
O
4
nanopa icles
and CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
, espec i ely. Theadso p ion esul s showed ha a op imum condi ions o con ac
ime o 40 min, pH o 5.5, and 0.8 g/L, he adso p ion e ficiency o he adso ben o Nd
+3
,Tb
+3
,andDy
+3
was
97.75, 96.83, and 97.85%, espec i ely. The ions adso p ion kine ic on o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
was in ac-
co dance wi h pseudo-second-o de (PSO) model. The e alua ion o equilib ium da a was pe o med by he iso-
he m models o Langmui and F eundlich. Fi ing he expe imen al da a o Tb
+3
and Dy
+3
was done be e wi h
F eunlich model han Langmui model,while fi ing es s o Nd
+3
adso p ion da a showed be e co e age using
Langmui model wi h a maximum adso p ion capaci y o 73.37 mg/g. The esul s o he pa ame e s o he mody-
namic showed he endo he mic and spon aneous p ope ies o he p ocess. Addi ionally, he e ficacy o he ad-
so ben was s udied using 0.2 M HNO
3
in ou adso p ions–deso p ion cycles. O e all, he ob ained esul s
demons a ed ha he en i onmen ally iendly magne ic bionanocomposi e adso ben can be applied e ec-
i ely o Nd
+3
,Tb
+3
,andDy
+3
adso p ion wi h a o able adso p ion e ficiency.
© 2020 Published by Else ie B.V.
1. In oduc ion
Ra e ea h elemen s (REEs) a e ge ing imp essi e conside a ions
and p og essi ely eques ed in inno a i e indus ies in iew o hei
no el p ope ies [1]. As o la e, hey ha e been disco e ed b oad de-
mands in ba e ies, elec onics, and chemical enginee ing [2,3]. Because
o eno mous and expanding local eques s, China educed i s amoun o
REEs send ou om 50,145 ons in 2009 o jus 31,130 ons in 2012.
These a e quan i ies may c ea e di ficul issues o REE applican s ou -
side o China, as p o ed by he c isis o REEs in 2011, eco ding high
cos s o hese elemen s [4]. This ci cums ance has addi ionally anima ed
many na ions, o example, Japanand mos EUMembe S a es ha don'
ha e anyso o essen ial REEs s o es on hei egion o sea ch o op ion
and auxilia y esou ces o REEs and o ex end hei own REEs indus y
so as o ge a wellsp ing o REEs, especially hea y REEs [5]. In his man-
ne , a p oduc i e me hod is expec ed o o e come all di ficul issues
wi h espec o REEs.
The con en ional me hodologies applied o REEs eco e y a e
chemical p ecipi a ion, memb ane sepa a ion, ion-exchange, e e se
osmosis, ex ac ion, and adso p ion [6–8]. Howe e , each me hod has
i s ad an ages and disad an ages. Fo ins ance, chemical p ecipi a ion
has he ad an age o low-cos and simple ope a ion, bu la ge amoun s
o chemical p oduc s a e p oduced, esul ing in landfill p oblems [9].
Memb ane sepa a ion me hod has head an ages o high sepa a ion e -
ficiency o hea y me al ions, ye low economic easibili y and high
main enance cos es ic i s applica ion on a la ge scale. Adso p ion
echnology, which is easy o pe o m, highly e ec i e, and low-cos , is
conside ed as a as and ela i ely inexpensi e app oach o me al ions
adso p ion [10]. Adso p ion o REEs has been in es iga ed by some ma-
e ials suchas bioso ben s [11–13], ca bon [14,15], silicao he ino ganic
[16–18], and polyme ic ma e ials [19,20].
Jou nal o Molecula Liquids 306 (2020) 112760
⁎Co esponding au ho s.
E-mail add esses: hamed eza.ja [email protected],hamed eza.ja [email protected]
(H. Ja adian), awfik@k upm.edu.sa (T.A. Saleh).
h ps://doi.o g/10.1016/j.molliq.2020.112760
0167-7322/© 2020 Published by Else ie B.V.
Con en s lis s a ailable a ScienceDi ec
Jou nal o Molecula Liquids
jou nal homepage: www.else ie .com/loca e/molliq
Algina e, as a aluable na u al polyme , has pulled in ex eme con-
side a ion. I is an o dina y polysaccha ide ha is made up o he esi-
dues o mannu onic (M) and gulu onic (G) acid (linea copolyme o
β-D-mannu onic acid and α-L-gulu onic acid uni s wi h(1–4)linkages)
[21]. This en i onmen ally iendly polyme has highligh s o cheap-
ness, plen i ul sou ces, biocompa ibili y, and hyd ophilici y. Mo e
o en han no , indus ially accessible algina es a e ex ac ion o
b own algae cell wall [22]. I has been b oadly u ilized in immobiliza ion
s udies owing o easy p epa a ion, hyd ophilici y and e ficien adso p-
ion o a ge con amina ions.
Chi osan (CS) as a na u al polysaccha ide is gene ally made using
he deace yla ion o chi in. I s de i a i es can be gene a ed by he unc-
ional g oups' modifica ion, o ins ance, eac i e hyd oxyl, amino, and
N-ace yl g oups [23]. Ca boxyme hyl chi osan (CMC) is conside ed as
he mos significan de i a i es amongs o he s. I is he esul o he
ca boxyla ion o chi osan ha has ca boxyme hyl subs i uen s on
amino and hyd oxyl g oups o he glucosamine uni s [24]. Because o
ha ing special cha ac e is ics such as non oxici y, hyd ophilici y, biode-
g adabili y, en i onmen ally iendly, and me al-chela ing capaci y, i is
iewed as a po en ial candida e o bioadso p ion. Ne e heless, i
couldn' be used o he eco e y o ions because o being wa e -
dissol able and ha ing weak chemical s abili y [25]. So as o de ea
his issue, modifica ion o CMC by o he biopolyme s such as algina e
and ino ganic nanopa icles can be ega ded as one o he bes ech-
niques o inc ease i s hyd olysis esis ance.
The pu pose o his s udy was o syn hesize he Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic nanopa icles by he hyd o he mal echnique and using he
syn hesized nanopa icles o he syn hesis o a bionanocomposi e in
gela ion p ocess o sodium algina e and ca boxyme hyl chi osan bio-
polyme s in a medium o CaCl
2
and glu a aldehyde. A e cha ac e izing
he p oduc wi h a ious echniques including FE-SEM, EDX, XRD, FT-IR,
and VSM, i was used as an adso ben o in es iga e he adso p ion e fi-
ciency o Nd
+3
,Tb
+3
, and Dy
+3
depending on adso ben dosage, pH,
con ac ime, ini ial me al ion concen a ion by pe o ming a se ies o
ba ch expe imen s. Va ious kine ic and iso he m models we e es ed
o fi ing he expe imen al da a. The modynamic pa ame e s (ΔS
°
,
ΔG
°
, and ΔH
°
) we e also e alua ed o find he p ope y o adso p ion
p ocess. To he bes o ou knowledge, he u iliza ion o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
has no been s udied o Nd
+3
,Tb
+3
,andDy
+3
adso p ion.
2. Ma e ials and me hods
2.1. Ma e ials and eagen s
Ca boxyme hyl chi osan and sodium algina e we e pu chased om
Nan ong Chem-Base Co, China, and PanReac AppliChem, espec i ely.
Nd(NO
3
)
3
.6H
2
O, Tb(NO
3
)
3
·6H
2
O, Dy(NO
3
).5H
2
O, Zn(NO
3
)
2
, Fe(NO
3
)
3
.6H
2
O, Ni(NO
3
)
2
·6H
2
O, and glu a aldehyde we e bough om Sigma-
Ald ich. Since he analy ical g ade o all chemicals was chosen, hey
we e u ilized wi hou u he pu ifica ion. The expe imen solu ions o
Nd
+3
,Tb
+3
, and Dy
+3
we e p epa ed by dilu ion o 1000 mg/L o ions.
The alues o pH we e egula ed ia adding a sui able amoun o 0.1 M
sodium hyd oxide o ni ic acid solu ionsand moni o ed by a pH me e .
2.2. Ins umen a ion and cha ac e iza ion
FT-IR spec a we e eco ded on a Pe kinElme , USA, by KB pelle .
XRD pa e n was eco ded by a GBC MMA ins umen wi h CuK
α
adia-
ion in he 2θ ange o 10–70
0
. A FE-SEM (Zeiss Neon-40, Ge many) was
also u ilized o cha ac e izing he p oduc s mo phology. The magne ic
p ope ies o he p oduc s we e explo ed a he oom empe a u e (RT)
by employing a VSM (Daghigh Ka i Co po a ion, I an). TGA was done
on a Me le TGA/SDTA 851e/LF/1100 he mobalance. The empe a u e
o he sample was inc eased om RT o 1000 °C ( a e = 10 °C/min)
unde cons an ni ogen flow. Fo analyzing Nd
+3
,Tb
+3
,andDy
+3
con-
cen a ion, an Agilen 4100 MP-AES Spec ome e was used.
2.3. Syn hesis o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic nanopa icles
The Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic nanopa icles we e syn hesized by
he hyd o he mal me hod. A mixed solu ion o 0.2 M Ni
2+
,0.2M
Zn
2+
and 2.6 M Fe
3+
was p epa ed in HCl solu ion, and hen NaOH so-
lu ion was in oduced unde ni ogen gas and he alue o he pH o he
mix u e was egula ed o 10.5. To his mix u e, 0.3 g o CTAB was added,
and hen i was placed in o an au ocla e (Teflon-lined s ainless s eel) a
200 °C o an o en o 8 h o hyd o he mal ea men . In he ollowing,
he empe a u e o he au ocla e was na u ally dec eased o RT. The
p ecipi a e was hen collec ed and washed wi h deionized wa e
(DW) se e al imes o each pH = 7. Finally, he ob ained pa icles
we e d ied a 50 °C.
2.4. Syn hesis o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic bionanocomposi e
The syn hesis p ocedu e o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
wasas ol-
lows: Sodium algina e (1 g) was dissol ed in 80 mL o DW a RT by a lab-
o a o y s i e . 0.50 g o he ca boxyme hyl chi osan was in oduced
in o he solu ion and homogeneously mixed. 0.7 g o he
Ni
0.2
Zn
0.2
Fe
2.6
O
4
wasadded o he mix u e o he biopolyme s. Toob ain
a homogeneous blend solu ion, he mix u e o biopolyme s and
magne ic pa icles was s i ed a he RT o 24 h. In he ollowing, i
was added in o he solu ion o calcium chlo ide 0.05 M and 2% glu-
a aldehyde o gela ion p ocess. A e he comple ion o gela ion
p ocess, an ex e nal magne ic field was u ilized o he sepa a ion
o he esul ing bionanocomposi e, and hen i was washed using
DW se e al imes o elimina e any emaining calcium chlo ide and
glu a aldehyde un il he pH o he solu ion eached 7. The washed
CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
bionanocomposi e was d ied a 50 °C. Fi-
nally, i was powde ed.
2.5. Ba ch adso p ion and eusabili y s udies
The s ock solu ions o me al ions we e p epa ed by dissol ing Tb
(NO
3
)
3
·6H
2
O, Nd(NO
3
)
3
.6H
2
O, and Dy(NO
3
).5H
2
O sepa a ely in DW
o achie e 1000 mg/L o each ion, and all he expe imen solu ions con-
aining 50mL o single ion p epa ed by dilu ion o each s ock solu ion o
he equi ed concen a ion we e agi a ed a 180 pm by a labo a o y
shake . Equal concen a ion o he ions was applied in single ba ch ad-
so p ion s udies. Fo s udying he influences o pH and adso ben dos-
age on he ions adso p ion e ficiency, ba ch adso p ion expe imen s
we e pe o med in he pH ange o 1.5–5.5 and dosage ange o
0.01–0.06 g, espec i ely. Fo he kine ic e alua ion, he adso ben was
added in o he solu ions wi h 30 mg/L ini ial concen a ion, and he
es s we e pe o med a di e en con ac ime (2.5–70 min). Ini ial
me al concen a ion in he ange o 30–300 mg/L a he op imum ime
was used o in es iga e he iso he m o he adso p ion. The e ec o
ionic s eng h was s udied wi h NaNO
3
solu ion a a ious concen a-
ions o 0.02, 0.04, 0.06, 0.08, and 0.1 M. To e alua e he modynamic pa-
ame e s, he expe imen s we e ca ied ou a h ee a ious
empe a u es o 25, 35 and 45 °C a a cons an ini ial concen a ion o
90 mg/L. The ions concen a ion in he solu ion was measu ed by an
Agilen 4100 MP-AES Spec ome e . The adso p ion e ficiency (%) and
capaci y o me al adso p ion by he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
we e
compu ed using he equa ions in he ollowing:
Adso p ion e iciency %ðÞ¼C0−Ce
ðÞ=Co100 ð1Þ
qe¼C0−Ce
ðÞV=mð2Þ
q ¼C0−C
ðÞV=mð3Þ
2H. Ja adian e al. / Jou nal o Molecula Liquids 306 (2020) 112760
whe e he q
e
and q
(mg/g) e e o he quan i ies o me al ionadso bed
a equilib ium and adso p ion ime in min, espec i ely. C
0
and C
e
show he ini ialand equilib iumconcen a ionso me al ion in mg/L, e-
spec i ely. C
e e s o he concen a ion o a me al ion in solu ion a
ime (min). Mo eo e , m e e s o he adso ben weigh (g), and V e-
e s o he solu ion olume in L.
To in es iga e he eusabili y o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
,a
gi en amoun o he adso ben was ea ed wi h 50 mL o 30 mg/L
me al solu ion a pH o 5.5 by a shake a speed o 180 pm o ob ain
he exhaus ed adso ben . The ions-loaded adso ben was sepa a ed
wi h an ex e nal magne ic field, washed by DW o elimina e he un-
adso bed ions and hen agi a ed o 2 h by 50 mL HNO
3
(0.2 M) eluen
solu ion. Subsequen ly, he egene a ed CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
was
sepa a ed and washed se e al imes wi h DW un il he solu ion pH
eached 7. The egene a ed adso ben was applied in ou cycles o ad-
so p ion wi h he same egene a ion p ocedu e.
3. Resul s and discussion
3.1. Analyses o he p oduc s
Fig. 1 indica es he XRD pa e n o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
. The peaks a
2θ= 18.13°, 30.07
°
,35.50
°
,37.08
°
,43.07
°
,53.95
°
,56.96
°
, and 63.89
°
a e
in ag eemen wi h he s anda d pa e n o nickel zinc e i e (JCPDS 08-
0234) [26]. Full Wid h a Hal Maximum (FWHM) o he s onges e-
flec ion o he XRD pa e n was u ilized o es ima e he a e age c ys al
size based on he Sche e equa ion as ollowing [27]:
D¼kλ=βcos θð4Þ
Whe e k shows he shape unc ion, 0.89, λ e e s o he X- ay adia-
ion wa eleng h, β e e s o he FWHM a 2θ=35.50
°
,andθshows he
di ac ion angle. Basedon he equa ion o Sche e , hecalcula ed alue
o D was 27.68 nm.
The Ni
0.2
Zn
0.2
Fe
2.6
O
4
FE-SEM image in Fig. 2A indica es ha he syn-
hesized pa icles a e nea ly sphe ical in shape and homogenous in dis-
ibu ion wi h a diame e o b100 nm. Fig. 2B shows he dis ibu ion o
he magne ic nanopa icles on he su ace o he CA/CMC o embedding
wi h he CA/CMC ha confi ms he success ul syn hesis o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic bionanocomposi e.
Fig. 3 indica es he FT-IR spec a o CA, CMC, Ni
0.2
Zn
0.2
Fe
2.6
O
4
, and
CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
. The FT-IR spec a o CA and CMC espec i ely
in Fig. 3AandBshowO H s e ching ib a ion a 3389 (CA) and 3436
(CMC) cm
−1
, ca boxylic g oups asymme ical s e ching a 1622 (CA)
and 1631 (CMC) cm
−1
, ca boxylic g oups symme ical s e ching a
1423 (CA) and 1411 (CMC) cm
−1
and C-O-C s e ching a 1052 (CA)
and 1061 (CMC) cm
−1
[28,29]. The FT-IR spec um o he
Ni
0.2
Zn
0.2
Fe
2.6
O
4
in Fig. 3C shows a b oad abso p ion band wi h a
alue o 3424 cm
−1
and less in ensi e band a 1633 cm
−1
ela ed o
he O H g oups s e ching ib a ion [30]. The bands a 2925 and
2853 cm
−1
espec i ely co espond o he an i-symme ic and symme -
ic C H ib a ionso CTAB[31]. The band a 567 cm
−1
ela es o he in-
he en me al s e ching ib a ions a he e ahed al si e (Fe O), and
he alue o 478 cm
−1
is ela ed o he oc ahed al me al (M-O)
s e ching [30]. The compa ison o he spec um in Fig. 3D wi h o he
spec a exp esses he success ul syn hesis o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
EDX was eco ded o analyze he elemen s o he p oduc s (Fig. 4).
Fig. 4A shows Ni, Zn, Fe, and O peaks ha confi m he o ma ion o he
Ni
0.2
Zn
0.2
Fe
2.6
O
4
. The elemen al analysis o he nanocomposi e in
Fig. 4B ep esen s simila peaks a ailable in Fig. 4A along wi h he
new peaks o N and Ca because o combining he nanopa icles wi h
CA and CMC. Sodium peak is no seen in he spec um o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
, sugges ing ha sodium ions we e eleased comple ely
om he ma ix o sodium algina e in o he solu ion du ing he
c osslinking eac ion p ocess o sodium algina e wi h calcium.
The CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
weigh loss cu e eco ded in he
ange o RT o 1000 °C is demons a ed in Fig. 5A. As i is seen, he e
a e h ee di e en weigh -loss s eps in he TGA cu e o he CA/CMC/
Fig. 1. (A) XRD pa e n o Ni
0.2
Zn
0.2
Fe
2.6
O
4
nanopa ciles; Pho o o Ni
0.2
Zn
0.2
Fe
2.6
O
4
nanopa icles (B) be o e d ying and (C) in he solu ion unde magne ic field a e d ying.
3H. Ja adian e al. / Jou nal o Molecula Liquids 306 (2020) 112760
Ni
0.2
Zn
0.2
Fe
2.6
O
4
.Ob iously, hefi s s ep (a ound 190 °C) wi h a weigh
loss o 8.77% can be a ibu ed o apped and physiso bed wa e e ap-
o a ion. The second s ep be ween a ound 190 and 550 °C is he la ges
weigh loss wi h he amoun o 35.08% ha could be due o he so p ion
and deg ada ion o CA and CMC. The las s ep wi h 22.95% weigh loss a
a empe a u e beyond 550 °C could be ela ed o he u he decompo-
si ion o CA and CMC and hei con e sion o CO
2
and H
2
O. A he end o
he p ocess, he esidue pe cen age is abou 33.2% ha is p incipally
assigned o he p esence o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
An impo an issue ela ed o he magne ic bionanocomposi e is ha
i should possess su ficien magne ic p ope ies o i s p ac ical applica-
ion. Acco ding o he magne ic hys e esis loops in Fig. 5B, hesa u a ion
magne iza ion alue o Ni
0.2
Zn
0.2
Fe
2.6
O
4
is abou 45.87emu/g ha indi-
ca es supe pa amagne ic beha io o he syn hesized p oduc . I is ob i-
ous om Fig. 5C ha he p ocess o he syn hesis o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
esul s in a dec ease o sa u a ion magne iza ion o
he alue o 14.14 emu/g. This decline is due o he combina ion o he
magne ic nanopa icles wi h CA and CMC. Despi e his di e ence, he
ions-loaded CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
could be easily sepa a ed by ap-
plying an ex e nal magne ic field om aqueous solu ion o a oid sec-
onda y pollu ion as indica ed in Fig. 5D.
3.2. pH e ec
pH o he solu ion as a key pa ame e o he adso p ion p ocess
a ec s solu ion chemis y, me al specia ion, adso p ion capaci y,
he ac i i y o adso ben unc ional g oups, and mechanism o ad-
so p ion. I is associa ed di ec ly wi h H
+
compe i ion wi h ions o
he occupa ion o he su ace ac i e si es o he adso ben . Adso p-
ion e ficiency alues o Nd
+3
,Tb
+3
,andDy
+3
on o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
as a pH unc ion a e demons a ed in Fig. 6A. Elec-
os a ic in e ac ion could ha e a key ole on Nd
+3
,Tb
+3
,andDy
+3
adso p ion on o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
a di e en pH alues.
I can be in e p e ed ha a lowe pH alues, he adso p ion e fi-
ciency o he adso ben is low and inc ease wi h inc easing solu ion
pH. A pH = 1.5 ha is highly acidic, he p o ona ion o he adso ben
unc ional g oups blocks he me al ions app oach o he binding si es
o he adso ben . The me al ions and H
+
ionscompe e o hesame
binding si es o he adso ben , leading o dec ease in adso p ion e fi-
ciency [32]. A pH = 1.5, adso p ion e ficiency alue is ze o o all
ions. When pH alues a e adjus ed be ween 2.5 and 5.5, adso p ion
e ficiency o Nd
+3
,Tb
+3
,andDy
+3
on o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
inc eases wi h pH inc ease owing o he educ ion
in compe i ion be ween H
+
ions and me al ions. The maximum ad-
so p ion e ficiency o all me al ions occu s a pH = 5.5. pH inc ease
beyond 5.5 was no in es iga ed o p ohibi he p ecipi a ion o he
ions in he o m o hyd oxide. Fu he expe imen s we e ca ied
ou a pH = 5.5 as op imum pH.
3.3. Con ac ime e ec
I is essen ial o conside he adso p ion a e in designing he ba ch
expe imen s. The influence o con ac ime on Nd
+3
,Tb
+3
, and Dy
+3
adso p ion on o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
bionanocomposi e is
shown in Fig. 6B. As can be obse ed, adso p ion e ficiency o he ad-
so ben inc eases apidly du ing he fi s pe iod and hen inc eases
slowly un il eaching equilib ium s a e. The expe imen al ou comes
indica e ha Nd
+3
,Tb
+3
,andDy
+3
adso p ion can be spli in o wo
defini e pa s: an ex emely apid ini ial adso p ion occu s in he
fi s 10 min, and hen much slowe adso p ion is seen o highe con-
ac ime. In gene al, app oxima ely 80% o he me al ions con ac
quickly in he fi s 10 min because o he p esence o la gely accessi-
ble ac i e si es o he adso ben and hen slowly inc ease owing o a
g adual dec ease in he ac i e si es and weakness o he d i ing o ce
and finally adso p ion eaches equilib ium [33]. The con ac ime o
40 min was aken as an op imum ime o adso p ion o Nd
+3
,
Tb
+3
,andDy
+3
.
Fig. 3. FT-IR spec a o (A) CA, (B) CMC, (C) Ni
0.2
Zn
0.2
Fe
2.6
O
4
,and(D)CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
Fig. 2. FE-SEM images o (A) Ni
0.2
Zn
0.2
Fe
2.6
O
4
and (B) CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
4H. Ja adian e al. / Jou nal o Molecula Liquids 306 (2020) 112760
[43] I.V. Melnyk, V.P. Goncha yk, L.I. Kozha a, G.R. Yu chenko, A.K. Ma ko sky, Y.L. Zub, B.
Alonso, So p ion p ope ies o po ous sp ay-d ied mic osphe es unc ionalized by
phosphonic acid g oups, Mic opo ous Mesopo ous Ma e . 153 (2012) 171–177.
[44] T. Kegl, I. Ban, A. Lobnik, A. Košak, Syn hesis and cha ac e iza ion o no el γ-Fe
2
O
3
-
NH
4
OH@SiO
2
(APTMS) nanopa icles o dysp osium adso p ion, J. Haza d. Ma e .
378 (2019), 120764.
[45] A. Neg ea, A. Gabo , C.M. Da idescu, M. Ciopec, P. Neg ea, N. Du eanu, A. Ba bulescu,
Ra e ea h elemen s emo al om wa e using na u al polyme s, Sci. Rep. 8 (2018)
316.
[46] Y.R. Lee, K. Yu, S. Ra i, W.S. Ahn, Selec i e adso p ion o a e ea h elemen s o e
unc ionalized C -MIL-101, Appl. Ma e . In e aces 10 (2018) 23918–23927.
[47] X.-H. Qi, K.-Z. Du, M.-L. Feng, Y.-J. Gao, X.-Y. Huang, M.G. Kana zidis, Laye ed
A
2
Sn
3
S
7
·1.25H
2
O(A= o ganic ca ion) as e ficien ion-exchange o a e ea h el-
emen eco e y, J. Am. Chem. Soc. 139 (12) (2017) 4314–4317.
[48] S.M.A. Koochaki-Mohammadpou , M. To ab-Mos aedi, A. Talebizadeh-Ra sanjani, F.
Nade i-Behdani, Adso p ion iso he m, kine ic, he modynamic, and deso p ion
s udies o lan hanum and dysp osium on oxidized mul iwalled ca bon nano ubes,
J. Dispe s. Sci. Technol. 35 (2014) 244–254.
[49] M.M. Yuso , N.R. Nik Mos apa, Md. Shaheen Sa ka , T.K. Biswas, Md. Lu o Rahman,
S.E. A shad, M.S. Sa jadi, A.D. Kulka ni, Syn hesis o ion imp in ed polyme s o se-
lec i e ecogni ion and sepa a ion o a e ea h me als, J. Ra e Ea h 35 (2017)
177–186.
[50] H.A. Madbouly, N.E. El-He ny, Y.A. El-Nadi, Adso p ion and sepa a ion o e bium
(III) and gadolinium(III) om aqueous ni a e medium using solid ex ac an , Sep.
Sci. Technol. (2019) 1–13.
[51] S. Tong, S. Zhao, W. Zhou, R. Li, Q. Jia, Modifica ion o mul i-walled ca bon nano ubes
wi h annic acid o he adso p ion o La, Tb and Lu ions, Mic ochim. Ac a 174
(2011) 257–264.
[52] D. Baybaş, U. Ulusoy, Polyac ylamide–clinop iloli e/Y-zeoli e composi es: cha ac e i-
za ion and adso p i e ea u es o e bium, J. Haza d. Ma e . 187 (1) (2011) 241–249.
[53] R. Akkaya, Syn hesis and cha ac e iza ion o a new low-cos composi e o he adso p-
ion o a e ea h ions om aqueous solu ions, Chem. Eng. J. 200 (2012) 186–191.
[54] R. Akkaya, Te bium adso p ion on o polyhyd oxye hylme hac yla e–hyd oxyapa i e
composi e and i s modified composi ion by phy ic acid, Desalin. Wa e T ea . 52
(2014) 1440–1447.
[55] F.A. Alakh as, K.A. Da i, M.S. Muba ak, Syn hesis and chela ing p ope ies o some
poly (Amidoxime-hyd oxamic acid) esins owa d some i alen lan hanide
me al ions, J. Appl. Polym. Sci. 97 (2) (2005) 691–696.
[56] M.A. A ia, S.I. Moussa, R.R. Sheha, H.H. Someda, E.A. Saad, Hyd oxyapa i e/NiFe
2
O
4
supe pa amagne ic composi e: acile syn hesis and adso p ion o a e elemen s,
Appl. Radia . Iso . 145 (2019) 85–94.
[57] N.S. Reddy, K.M. Rao, S.V. K ishna, C.S. Ha, Syn hesis o 1–ac yloyl–3–phenyl hio-
u ea based pH sensi i e hyd ogels o emo al o sama ium and e bium, Mac omol.
Res. 24 (2016) 494–501.
[58] M.R. Awual, N.H. Alha hi, Y. Okamo o, M.R. Ka im, M.E. Halim, M.M. Hasan, M.M.
Rahman, M.M. Islam, M.A. Khaleque, M.C. Sheikh, Ligand field e ec o Dysp o-
sium(III) and lu e ium(III) adso p ion and EXAFS coo dina ion wi h no el compos-
i e nanoma e ials, Chem. Eng. J. 320 (2017) 427–435.
[59] R.M. Ashou , R. El-Sayed, A.F. Abdel-Magied, A.A. Abdel-Khalek, M.M. Ali, K.
Fo sbe g, A. Uheida, M. Muhammed, J. Du a, Selec i e sepa a ion o a e ea h
ions om aqueous solu ion using unc ionalized magne i e nanopa icles: kine ic
and he modynamic s udies, Chem. Eng. J. 327 (2017) 286–296.
[60] H. Aghayan, A. Mahjoub, A. Khanchi, Sama ium and dysp osium emo al using 11-
molybdo- anadophospho ic acid suppo ed on Z modified mesopo ous silica SBA-
15, Chem. Eng. J. 225 (2013) 509–519.
[61] T. Kaneko, F. Naga a, S. Kugimiya, K. Ka ob, Op imiza ion o ca boxyl- unc ionalized
mesopo ous silica o he selec i e adso p ion o dysp osium, J En i onmen Chem
Eng 6 (2018) 5990–5998.
[62] X. Zheng, Y. Zhang, T. Bian, Y. Zhang, Z. Li, J. Pan, Oxidized ca bon ma e ials coope -
a i e cons uc ionic imp in ed cellulose nanoc ys als films o e ficien adso p ion
o Dy(III), Chem. Eng. J. 381 (2020), 122669.
[63] X. Zheng, E. Liu, F. Zhang, Y. Yan, J. Pan, E ficien adso p ion and sepa a ion o dys-
p osium om NdFeB magne s in an acidic sys em by ion imp in ed mesopo ous sil-
ica sealed in a dialysis bag, G een Chem. 18 (2016) 5031–5040.
[64] İ. Ka a, D. Yilmaze , S. Tunali Aka , Me akaolin based geopolyme as an e ec i e ad-
so ben o adso p ion o zinc(II) and nickel(II) ions om aqueous solu ions, Appl.
Clay Sci. 139 (2017) 54–63.
[65] D. Alipou , A.R. Kesh ka , M.A. Moosa ian, Adso p ion o ho ium (IV) om simu-
la ed adioac i e solu ions using a no el elec ospun PVA/TiO
2
/ZnO nanofibe ad-
so ben unc ionalized wi h me cap o g oups: s udy in single and mul i-
componen sys ems, Appl. Su . Sci. 366 (2016) 19–29.
[66] M. Rajabi, K. Mahanpoo , O. Mo adi, P epa a ion o PMMA/GO and PMMA/GO-Fe
3
O
4
nanocomposi es o malachi e g een dye adso p ion: kine ic and he modynamic
s udies, Compos Pa B Eng 167 (2019) 544–555.
[67] H. Ja adian, P. Vahedian, M. Toosi, Adso p ion cha ac e is ics o Ni(II) om aqueous
solu ion and indus ial was ewa e on o Polyaniline/HMS nanocomposi e powde ,
Appl. Su . Sci. 284 (2013) 13–22.
[68] N. Subedi, A. Lähde, E. Abu-Danso, J. Iqbal, A. Bha naga , A compa a i e s udy o
magne ic chi osan (Chi@Fe
3
O
4
) and g aphene oxide modified magne ic chi osan
(Chi@Fe
3
O
4
GO) nanocomposi es o e ficien emo al o C (VI) om wa e , In . J.
Biol. Mac omol. 137 (2019) 948–959.
11H. Ja adian e al. / Jou nal o Molecula Liquids 306 (2020) 112760

117
118
ANNEX II
Response su ace me hodology based on cen al composi e design o simul aneous
adso p ion o a e ea h elemen s using nanopo ous calcium algina e/ca boxyme hyl chi osan
mic obiocomposi e powde con aining Ni0.2Zn0.2Fe2.6O4 magne ic nanopa icles: Ba ch and
column s udies.
Hamed eza Ja adian, Mon se a Ruiz, Ana Ma ia Sas e,
In e na ional Jou nal o Biological Mac omolecules, 154 (2020) 937-953.
h ps://doi.o g/10.1016/j.ijbiomac.2020.03.131
119
Response su ace me hodology based on cen al composi e design o
simul aneous adso p ion o a e ea h elemen s using nanopo ous
calcium algina e/ca boxyme hyl chi osan mic obiocomposi e powde
con aining Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic nanopa icles: Ba ch and
column s udies
Hamed eza Ja adian
a,
⁎, Mon se a Ruiz
b
, Ana Ma ia Sas e
a
a
Depa men o Chemical Enginee ing, ETSEIB, Uni e si a Poli ècnica de Ca alunya, Diagonal 647, 08028 Ba celona, Spain
b
Depa men o Chemical Enginee ing, EPSEVG, Uni e si a Poli ècnica de Ca alunya, A . Víc o Balague , s/n, 08800 Vilano a i la Gel ú, Spain
abs ac a icle in o
A icle his o y:
Recei ed 22 No embe 2019
Recei ed in e ised o m 20 Feb ua y 2020
Accep ed 14 Ma ch 2020
A ailable online xxxx
Keywo ds:
Calcium algina e
Ca boxyme hyl chi osan
Ni
0.2
Zn
0.2
Fe
2.6
O
4
Adso p ion
Ra e ea h elemen s
RSM
In his esea ch pape , he u iliza ion o he magne ic calcium algina e/ca boxyme hyl chi osan/Ni
0.2
Zn
0.2
Fe
2.6
O
4
(CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
) was in es iga ed o he simul aneous aqueous adso p ion o Nd (III), Tb (III), and Dy
(III). The magne ic p oduc s we e cha ac e ized by FE-SEM, EDX, XRD, FT-IR, TGA, and VSM echniques. The sa -
u a ion magne iza ion alue o Ni
0.2
Zn
0.2
Fe
2.6
O
4
and CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
was ound o be 45.87 and
14.14 emu/g, espec i ely. Using RSM, a quad a ic polynomial equa ion was ob ained o p edic he adso p ion
e ficiency o each ion. Unde he condi ions o pH = 5.5, adso ben dosage o 0.1 g, ini ial concen a ion o
30 mg/L, and con ac ime o 53 min p edic ed by RSM, he adso p ion e ficiencies o Nd (III), Tb (III), and Dy
(III) we e espec i ely 95.72, 96.17, and 99.44%. The iso he m and kine ic da a we e espec i ely fi ed well
wi h F eundlich and pseudo-second-o de (PSO) models. The deso p ion o he loaded ions was e ec i ely ca -
ied ou by 0.2 M HNO
3
, and he adso ben was consecu i ely u ilized wi h 2.54, 1.63, and 1.16% dec ease in ad-
so p ion e ficiency o Nd (III), Tb (III), and Dy (III), espec i ely, a e he o h cycle. Addi ionally, he adso p ion
beha io o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
owa ds Nd (III), Tb (III), and Dy (III) was s udied by using a fixed-bed
column echnique.
© 2020 Published by Else ie B.V.
1. In oduc ion
Ra e ea h elemen s (REEs) a e egula ly alluded in e ms o “seeds
o echnology”due o hei u iliza ion in elec onic de ices, high
s eng h las ing magne s, g een ene gy sec o s, lase s, au omo i e ca a-
ly ic con e e s, fibe supe conduc o s/op ics, e c. [1,2]. Because o he
p og essing ad ancemen in new end-se ing inno a ions, he e is
an o e -expanding in e es o REEs in he uni e sal ma ke s, wi h an
accen ua ion on dis inguishing new o igins o gua an ee sa is ac o y
supply o u ilizing in he p esen and u u e. This issue becomes mo e
impo an since N90% o mine p oduc ion o a e ea h occu s in China,
and i s REEs expo was dec eased 19,015 ons om 2009 o 2012, lead-
ing o se ious p oblems o REE use s ou side o China. The e o e, REEs
eco e y om was es has been one o he mos inc edible wo ies in
he ongoing yea s [3].
A ew echniques, such as sol en ex ac ion, chemical p ecipi a ion,
ion exchange, memb ane sepa a ion, adso p ion and so on, ha e been
applied o he REEs eco e y [4,5]. In es iga o s ha e no ed adso p ion
as a s andou echnique because o being easy, cos -e ec i e, and en i-
onmen ally iendly o REEs eco e y in compa ison wi h he egula
echniques [6].
Algina e, as a na u al biopolyme , is ex ac ed om b own algae.
Some o i s benefi s, such as biodeg adabili y, biocompa ibili y, being
cheap and non oxic, make i a g ea po en ial ma e ial o be b oadly
and e ec i ely u ilized in wa e ea men [7–10]. I ends o be u ilized
o p oduce hyd ogels unde condi ions o mode a e pH and empe a-
u es. Algina e can likewise be al e ed ia physicochemical p ocedu es
o enhance i s chemical and mechanical s eng h [11]. In his manne ,
i s adso p ion beha io can beinc eased by aising i sadso p ion capac-
i y [12]. The u iliza ion o algina e in he o m o hyd ogel beads is a yp-
ical echnique o enhance i s adso p ion capaci y [13].
In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953
⁎Co esponding au ho a : Depa men o Chemical Enginee ing, ETSEIB, Uni e si a
Poli ècnica de Ca alunya, Diagonal 647, 08028 Ba celona, Spain
E-mail add ess: hamed eza.ja [email protected] (H. Ja adian).
h ps://doi.o g/10.1016/j.ijbiomac.2020.03.131
0141-8130/© 2020 Published by Else ie B.V.
Con en s lis s a ailable a ScienceDi ec
In e na ional Jou nal o Biological Mac omolecules
jou nal homepage: h p://www.else ie .com/loca e/ijbiomac
Chi osan-based adso ben ma e ials a e b oadly applied o he ad-
so p ion emo al o con amina ions aqueous solu ion [14]. Chi osan
possesses aluable cha ac e is ics, o example, biodeg adabili y, hyd o-
philici y, non oxici y, biocompa ibili y, high mechanical s eng h, film
p epa a ion, and an ibac e ial cha ac e is ics [15].I s chemical s uc u e
con ains amino(-NH
2
) and hyd oxyl (-OH) g oups as majo ac i e unc-
ional g oups o adso p ion o me al ions om aqueous media [16,17].
The dissol abili y o chi osan can be enhanced by modi ying i s s uc-
u e wi h –COOH g oups wi hou influencing on he men ioned cha ac-
e is ics [18]. Besides, he ca boxyl ga he ing p esen ed in
ca boxyme hyl chi osan (CMC) is addi ionally use ul o he adso p ion
o me al ions.
I is necessa y o easily sepa a e adso ben s ha a e applied in he
o m o ul afine powde o he sepa a ion o me al ions om aqueous
media. Fo his pu pose, cen i uga ion and fil a ion me hods a e no
e ficien o comple ely sepa a e such a powde om aqueous media,
while adso ben s ha ing magne ic p ope ies can be easily sepa a ed
using an ex e nal magne ic field [19]. The ac i e su ace and small size
o nanopa icles lead o hei easy agg ega ion in aqueous media [20].
To sol e his issue, amending he s abili y, inc easing he applica ion
o magne ic nanopa icles, and hei combining wi h biopolyme s
such as algina e and ca boxyme hyl chi osan could be conside ed as e -
ec i e me hods.
The goal o his s udy was o syn hesize he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
as a magne ic adso ben o simul aneous adso p ion
o Nd (III), Tb (III), and Dy (III) ions om aqueous solu ion. The adso -
ben was analyzed by FE-SEM, EDX, XRD, FT-IR, TGA, and VSM ech-
niques. The influences o adso ben dosage, con ac ime, and ini ial
concen a ion as main pa ame e s we e s udied, and RSM-CCD was
used o op imize hem. The kine ic and iso he m models we e applied
o fi ing he expe imen al da a. The pe o mance o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
was also e alua ed in a fixed-bed column.
2. Ma e ials and me hods
2.1. Ma e ials and eagen s
Ca boxyme hyl chi osan and sodium algina e we e pu chased om
Nan ong Chem-Base Co, China, and PanReac AppliChem, espec i ely.
Dy(NO
3
)
3
.5H
2
O was pu chased om Al a Aesa . Nd(NO
3
)
3
.6H
2
O, Tb
(NO
3
)
3
·6H
2
O, Zn(NO
3
)
2
.6H
2
O, Fe(NO
3
)
3
.9H
2
O, Ni(NO
3
)
2
·6H
2
O, CaCl
2
,
and glu a aldehyde we e bough om Sigma-Ald ich. Analy ical g ade
ma e ials we e used wi hou u he pu ifica ion. The expe imen solu-
ions o Nd (III), Tb (III), and Dy (III) ions we e made by dilu ion o
1000 mg/L o ions. HNO
3
o NaOH solu ion wi h he mola i y o 0.1
was u ilized o ca e ully adjus he pH o he solu ions.
Table 1
CCD le els, expe imen al design and he esponses.
Symbol −Uni Le els
−−α(−2) Low (−1) Cen al (0) High (1) +α(+2)
X
1
Con ac ime min 2 19 36 53 70
X
2
Adso ben dosage g 0.05 0.125 0.2 0.275 0.35
X
3
Nd (III) concen a ion mg/L 30 45 60 75 90
X
4
Tb (III) concen a ion mg/L 30 45 60 75 90
X
5
Dy (III) concen a ion mg/L 30 45 60 75 90
Run Fac o s Nd adso p ion e ficiency
(%)
Tb adso p ion e ficiency
(%)
Dy adso p ion e ficiency
(%)
X1 X2 X3 X4 X5 Obse ed P edica ed Obse ed P edica ed Obse ed P edica ed
1 36 0.2 60 60 30 90.76 90.92 95.85 96.19 97.53 98.38
2 53 0.275 75 75 75 94.56 95.81 96.87 97.99 98.11 99.49
3 36 0.2 90 60 60 87.96 86.97 90.53 89.74 92.89 92.17
4(C) 36 0.2 60 60 60 91.45 91.56 94.03 93.83 95.75 95.59
5 19 0.125 45 45 75 67.08 65.91 70.16 68.76 73.17 71.86
6 36 0.2 60 90 60 89.7 90.18 91.64 91.83 92.85 92.90
7 19 0.125 75 75 75 54.56 53.65 57.87 57.07 59.06 58.32
8 19 0.125 75 45 45 62.65 61.90 67.59 66.71 72.45 71.31
9 70 0.2 60 60 60 88.12 86.43 90.56 88.55 92.92 90.59
10 53 0.125 75 75 45 71.98 71.84 77.64 77.97 79.51 79.74
11(C
a
) 36 0.2 60 60 60 91.97 91.56 94.46 93.83 96.01 95.59
12 2 0.2 60 60 60 65.78 67.47 67.73 70.34 69.45 72.25
13 53 0.275 75 45 45 92.56 93.97 95.54 96.59 97.98 98.96
14 19 0.275 75 45 75 89.1 89.74 91.94 91.86 95.7 95.71
15 53 0.125 45 45 45 87.6 87.20 90.19 89.92 92.85 92.51
16 36 0.2 30 60 60 94.46 95.45 96.21 97.60 98.25 99.45
17(C) 36 0.2 60 60 60 91.72 91.56 94.09 93.83 95.71 95.59
18(C) 36 0.2 60 60 60 90.96 91.56 93.52 93.83 95.35 95.59
19(C) 36 0.2 60 60 60 91.58 91.56 93.85 93.83 95.32 95.59
20 36 0.2 60 30 60 95.64 95.16 94.43 94.84 98.65 99.07
21 19 0.275 45 45 45 92.75 92.82 94.74 94.09 97.54 96.76
22 53 0.275 45 75 45 94.56 95.23 96.44 97.00 98.45 99.05
23 19 0.275 75 75 45 92.49 92.81 94.63 94.58 96.2 95.99
24 53 0.125 45 75 75 76.01 75.45 79.06 78.86 81.63 81.69
25 19 0.125 45 75 45 59.07 57.58 68.72 67.35 69.38 67.85
26(C) 36 0.2 60 60 60 91.7 91.56 93.65 93.83 95.9 95.59
27 53 0.125 75 45 75 65.46 65.63 72.26 72.55 76.16 76.61
28 19 0.275 45 75 75 90.07 89.98 94.78 94.21 96.59 96.21
29 53 0.275 45 45 75 94.11 95.10 96.07 96.59 98.5 99.31
30 36 0.05 60 60 60 35.32 37.94 45.19 47.04 47.59 49.51
31 36 0.35 60 60 60 92.14 89.52 94.22 92.97 96.36 94.91
32 36 0.2 60 60 90 85.56 85.40 89.35 89.61 93.01 92.63
a
Cen al poin .
938 H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953

2.2. Ins umen a ion and cha ac e iza ion
The eco d o FT-IR spec a we e pe o med om 4000 o 450 cm
−1
on a Pe kinElme , USA, by he KB disk me hod. To iden i y he c ys al-
line s uc u e o he p oduc , XRD pa e n was aken down on a GBC
MMA ins umen wi h CuK
α
adia ion (wa eleng h λ= 0.154 nm) in
he 2θ ange o 10–70
0
. The mo phological s uc u e and pa icle size
o he p oduc s we e de e mined by FE-SEM (Zeiss Neon-40,
Ge many). The magne ic cha ac e is ics o he p oduc s we e s udied
using VSM (Daghigh Ka i Co po a ion, I an) a oom empe a u e
(RT). The mal analyses we e done on a Me le TGA/SDTA 851e/LF/
1100 he mobalance. The empe a u e o he samples was inc eased
om RT o 1000 °C a a e = 10 °C/min unde a cons an flow o N
2
.
Fo analyzing he concen a ion o Nd (III), Tb (III), and Dy (III), an
Agilen 4100 MP-AES Spec ome e was used. The Design Expe so -
wa e, e sion 10, was u ilized o define he expe imen al design by
CCD and analyze he eg ession o he expe imen al da a.
2.3. Syn hesis o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic nanopa icles
The Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne icnanopa icles we e syn hesized using
hyd o he mal me hod. A mix u e o 0.2 M Ni
2+
, 0.2 M Zn
2+
and 2.6 M
Fe
3+
was p epa ed in HCl solu ion, and hen NaOH solu ion was
added in o mixed solu ion unde ni ogen gas and he mix u e pH
alue was adjus ed o 10.5. 0.3 g o CTAB was added o he mix u e,
and hen i was placed in o an au ocla e (Teflon-lined s ainless s eel)
and main ained a 200°C o an o en o 8 h o hyd o he mal ea men .
The empe a u e o he au ocla e was na u ally dec eased o RT, and he
p ecipi a e wascollec ed and insed se e al imes wi h deionized wa e
o each neu al pH. Finally, he ob ained pa icles we e d ied a 50 °C.
2.4. Syn hesis o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic bionanocomposi e
The syn hesis p ocedu e o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
wasas ol-
lows: Sodium algina e (1 g) was dissol ed in 80 mL o deionized wa e
a RT using a labo a o y s i e . 0.5 g o he ca boxyme hyl chi osan
powde was added in o he solu ion and homogeneously mixed. 0.7 g
o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
was added o he mix u e o he biopolyme s.
To ob ain a homogeneous blend solu ion, he mix u e o biopolyme s
and magne ic pa icles was s i ed a RT o 24 h. Then, i was added
o he solu ion o calcium chlo ide 0.05 M and 2% glu a aldehyde o
he gela ion p ocess. An ex e nal magne ic field was used o sepa a e
he esul ing bionanocomposi e om solu ion, and hen i was washed
se e al imes wi h deionized wa e o emo ing emaining calcium
chlo ideand glu a aldehyde un il he pH alue hesolu ion was eached
7. The CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
bionanocomposi e was d ied a 50 °C.
Finally, i was powde ed.
2.5. Ba ch adso p ion
The adso p ion expe imen s o Nd (III), Tb (III), and Dy (III) by he
CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
bionanocomposi e we e done in 125 mL
flasks con aining 50 mL solu ions p epa ed om he dilu ion o
1000 mg/L s ock solu ions a di e en pHs, adso ben dosages, con ac
imes, and ini ial concen a ions wi h he a io o 1:1:1. The agi a ion
o he flasks was ca ied ou on a labo a o y shake ( pm = 180).
Fig. 1. (A) XRD pa e n o Ni
0.2
Zn
0.2
Fe
2.6
O
4
nanopa icles; pho o o Ni
0.2
Zn
0.2
Fe
2.6
O
4
nanopa icles (B) be o e d ying and (C) in he solu ion unde magne ic field a e d ying.
939H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953
Fig. 2. FE-SEM images o (A) Ni
0.2
Zn
0.2
Fe
2.6
O
4
and (B) CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
940 H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953
A e adso p ion p ocess o a p edefined ime, he adso ben was ex e -
nally sepa a ed by a magne ic field, and he adso p ion e ficiency and
adso p ion capaci y o he me al ions by he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
we e compu ed using he equa ions as ollowing:
Adso p ion e iciency %ðÞ¼
C0Ce
C0100 ð1Þ
qe¼ðC0CeÞV
mð2Þ
q ¼ðC0C ÞV
mð3Þ
whe e q
e
and q
(mg/g) espec i ely e e o he quan i ies o me al ion
adso bed on he adso ben a equilib ium and adso p ion ime (min),
C
0
(mg/L) is he ini ial concen a ion o me al ion, and C
e
(mg/L) is he
equilib ium concen a ion o me al ion. Mo eo e , C
e e s o he con-
cen a ion o me al ion in solu ion a ime , V is he olume (L) o solu-
ion, and m e e s o he weigh (g) o he adso ben .
2.6. Cen al composi e design
Expe imen al design is applied by in es iga o s o dec ease he
numbe o expe imen s in he adso p ion p ocess. I also p esen s help-
ul in o ma ion abou he e ec o independen pa ame e s indi idually
and/o in e ac i ely ha leads o a dec ease in expe imen al e o [21].
RSM was u ilized o model he adso p ion p ocess o he ions by in es-
iga ing he independen a iables including adso ben dosage, con ac
ime, ini ial concen a ion, and esponse (ions adso p ion e ficiency).
Fo simul aneous adso p ion o Nd (III), Tb (III), and Dy (III) ions by
he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
by using ba ch mode, CCD was u ilized
a fi e le els (−α(−2), low (−1), cen al (0), high (+1) and +α
(+2)) (Table 1).
Analysis o a iance (ANOVA) was used o ob ain in o ma ion abou
he adequacy o he models by e alua ing coe ficien o de e mina ion
(R[2]), lack o fi ,and heFishe es (F- alue) alues [22]. The quad a ic
polynomial model o esponse e sus he independen a iables was
p esen ed as ollows [23]:
Y¼β0þX
k
i¼1
βixiþX
k
i¼1X
k
j¼1
βijxixjþX
k
i¼1
βiix2
iþεð4Þ
whe e Y e e s o he p edic ed esponse (adso p ion e ficiency), and β
0
,
β
i
,β
ii
,andβ
ij
, espec i ely e e o he cons an coe ficien , linea coe fi-
cien , quad a ic coe ficien , and in e ac ion coe ficien . No ably, x
i
and x
j
a e he independen a iables, k shows he numbe o he independen
a iables, and εis he esidual e o .
2.7. Column mode
Fixed-bed column in es iga ion is necessa y o success ully design a
p ocess and s udy he beha io o adso ben in a la ge-scale u iliza ion.
To in es iga e he fixed-bed column, a columnmade o glass wi h an in-
e nal diame e o 0.5 cm and a leng h o 12 cm was used. 0.3 g o he
adso ben was mixed wi h 1.8 g o acid-cleaned sand, and he mix u e
was packed in he column be ween wo laye s o glass wool. Sand was
applied o dec ease he p essu e d op. The final heigh o he mix u e
in he column was abou 6.5 cm. An upwa d flow a e (1 mL/min)
was p o ided by a pe is al ic pump o flush he column wi h deionized
wa e o 1 h. Then, he column was ed wi h a e na y solu ion o he
ions a 30 mg/L ini ial concen a ion as an influen o 520 min. The col-
lec ion o he e fluen was pe o med e e y 10 min by a ac ion collec-
o , and he concen a ion o he ions was de e mined by Agilen 4100
MP-AES Spec ome e .
The b eak h ough cu e is usually shown by C
/C
0
e sus
ime. The amoun o ion adso bed (q
o al
,mg)wasob ainedby
calcula ing he cu e o b eak h ough (uppe a ea) by using
he ollowing equa ion:
q o al ¼Q
1000Z 0
o al 1−C
C0
 ð5Þ
whe e Q is he flow a e (mL/min) ha was de e mined ia di i-
sion o he e fluen olume (V
e
,mL) o he o al ime(
o al
,
min):
Q¼Ve
o al
ð6Þ
The en i e quan i y o he me als passed h ough he column (mg)
was ob ained by he ollowing equa ion:
m o al ¼C0Q o al
1000 ð7Þ
The o al me al adso p ion e ficiency was calcula ed om he
a io o he en i e quan i y o he me als sen o he column
(q
o al
) o heme almassadso bed(m
o al
) by he ollowing
equa ion:
Adso p ion e iciency ¼q o al
m o al
100 ð8Þ
The capaci y o equilib ium adso p ion (q
e
(mg/g)) and he equilib-
ium me al concen a ion (C
e
(mg/L)) we e espec i ely compu ed
using Eqs. (9) and (10) as ollowing:
qe¼q o al
mð9Þ
Ce¼m o al−q o al
Ve
100 ð10Þ
whe e m shows he adso ben mass (g).
2.8. E o analysis
E o analysis was used o op imize he fi ness o he expe imen al
da a ob ained om he non-linea app oach. In his s udy, Chi-squa e
(χ
2
) wasemployed o compa e he alidi yo each model by he ollow-
ing equa ion:
χ2¼X
n
i¼1
qe;exp−qe;cal

qe;cal
2
ð11Þ
whe e n shows he numbe o da a poin s, q
e,exp
is he expe imen al ca-
paci y o he adso ben , and q
e,cal
e e s o he compu ed capaci y o he
adso ben .
3. Resul s and discussion
3.1. P oduc s cha ac e iza ion
Fig. 1 indica es he XRD pa e n o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
. The peaks a
2θ= 18.13°, 30.07°, 35.50°, 37.08°,43.07°, 53.95°, 56.96° and 63.89° a e
in ag eemen wi h he s anda d pa e n o nickel zinc e i e (JCPDS 08-
0234) [24]. Full Wid h a Hal Maximum (FWHM) o he s onges e-
flec ion o he XRD pa e n was used o es ima e he a e age c ys al
size based on he Sche e equa ion as ollowing [25]:
D¼kλ=βcos θð12Þ
941H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953
whe e k e e s o he unc ion o shape (k = 0.89), and λ e e s o he
adia ion X- ay wa eleng h. Mo eo e , βand θ espec i ely e e o
he Full Wid h a Hal Maximum (FWHM) a 2θ= 35.50
°
, and he di -
ac ion angle. Based on he Sche e equa ion, he calcula ed alue o
Dwas27.68nm.
The FE-SEM image o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
in Fig. 2A indica es
ha he syn hesized pa icles a e nea ly sphe ical in shape and
homogenous in dis ibu ion wi h a diame e b100 nm. Fig. 2B
shows he dis ibu ion o he magne ic nanopa icles on he su -
ace o he CA/CMC o embedding wi h he CA/CMC ha con-
fi ms he success ul syn hesis o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic bionanocomposi e.
Fig. 3 indica es he FT-IR spec um o CA, CMC, Ni
0.2
Zn
0.2
Fe
2.6
O
4
and CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
. The FT-IR spec um o CA and CMC
in Fig. 3A and B, espec i ely, shows O H s e ching ib a ion a
3389 (CA) and 3436 (CMC) cm
−1
, ca boxyl g oups asymme ical
s e ching a 1622 (CA) and 1631 (CMC) cm
−1
, ca boxyl g oups sym-
me ical s e ching a 1423 (CA) and 1411 (CMC) cm
−1
and C-O-C
s e ching a 1052 (CA) and 1061 (CMC) cm
−1
[26,27]. The FT-IR
spec um o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
in Fig. 3C shows a b oad band a
a ound 3424 cm
−1
and less in ensi e band a 1633 cm
−1
ha a e e-
la ed o he O H g oups s e ching ib a ion [28]. The bands a 2925
and 2853 cm
−1
a e assigned o he an i-symme ic and symme ic
C H ib a ions o CTAB [29]. The band a 567 cm
−1
a ibu es o in-
insic me al s e ching ib a ions a he e ahed al si e (Fe O),
and oc ahed al me al s e ching(M-O)isseena a ound478cm
−1
[28]. The success ul syn hesis o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
can
be confi med by compa ing i s spec um shown in Fig. 3Dwi h
o he spec a.
N
2
adso p ion–deso p ion iso he m and he co esponding Ba e -
Joyne -Halenda (BJH) po e size dis ibu ion o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
a e shown in Fig. 4. The ni ogen adso p ion-
deso p ion iso he m o he sample in Fig. 4A is assigned o ype IV indi-
ca ing he p esence o mesopo ous s uc u e. The B unaue –Emme –
Telle (BET) su ace a ea, po e olume, and po e size (ob ained by he
BJH me hod (Fig. 4B)) we e calcula ed o be 7.1143 m
2
/g,
0.034971 cm
3
/g, and 19.0379 nm, espec i ely. The esul s clea ly
demons a e he o ma ion o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
wi h nano
size po es.
EDX was eco ded o analyze he elemen s o he p oduc s, and
he esul s a e p esen ed in Fig. 5.Fig. 5A shows Ni, Zn, Fe, and O
peaks ha confi m he o ma ion o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
. The ele-
men al analysis o he nanocomposi e in Fig. 5B ep esen s simila
peaks a ailable in Fig. 5A along wi h he new peaks o N and Ca be-
cause o combining he nanopa icles wi h CA and CMC. Sodium peak
is no seen in he spec um o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
,sugges -
ing ha sodium ions we e eleased comple ely om he ma ix o so-
dium algina e in o he solu ion du ing he c osslinking eac ion
p ocess o sodium algina e wi h calcium. EDX spec um was also e-
co ded a e he adso p ion p ocess and he esul is p esen ed in
Fig. 5C. The exis ence o Nd (III), Tb (III), and Dy (III) in he spec um
s ongly confi ms he success ul adso p ion o hese ions by he CA/
CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
The CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
weigh loss cu e eco ded in he
ange o RT o 1000 °C is demons a ed in Fig. 6. As i is seen, he e
a e h ee di e en weigh -loss s eps in he TGA cu e o he CA/
CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
. Ob iously, he fi s s ep (a ound 190 °C)
wi h a weigh loss o 8.77% can be a ibu ed o apped and
physiso bed wa e e apo a ion. The second s ep be ween a ound
190 and 550 °C is he la ges weigh loss wi h he amoun o
35.08% ha could be due o so p ion and deg ada ion o CA and
CMC. The las s ep wi h 22.95% weigh loss a empe a u e beyond
550 °C could be ela ed o he u he decomposi ion o CA and
CMC and hei con e sion o CO
2
and H
2
O. A he end o he p ocess,
he esidue pe cen age is abou 33.2% ha is p incipally assigned o
he p esence o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
Acco ding o he magne ic hys e esis loops in Fig. 7A, he mag-
ne ic sa u a ion alue o Ni
0.2
Zn
0.2
Fe
2.6
O
4
is abou 45.87 emu/g
ha indica es he supe pa amagne ic beha io o he syn hesized
p oduc . Based on Fig. 7B, i is ob ious ha he p ocess o he syn he-
sis o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
esul s in a dec ease o sa u a ion
magne iza ion o he alue o 14.14 emu/g. This decline is due o
combining he magne ic nanopa icles by CA and CMC. Despi e his
di e ence, he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
can be easily sepa a ed
om aqueous solu ion using an ex e nal magne ic field o a oid sec-
onda y pollu ion. Fig. 7C shows he easy sepa a ion o he me al ions-
loaded adso ben om he solu ion by applying an ex e nal mag-
ne ic field.
3.2. E ec o pH
Solu ion pH is conside ed as an essen ial pa ame e in he p ocess o
adso p ion owing o i s e ec on me al ionssolubili y, coun e ions con-
cen a ion on he adso ben unc ional g oups, and he adso ba e ioni-
za ion deg ee. In his s udy, he influence o pH alue on he p ocess
o adso p ion was conside ed om 1.5 o 5.5. The pH
ZPC
o he CA/
CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
was ound o be 6. Since he p ecipi a ion o he
ions may occu a pH alues highe han 5.5, he expe imen s we e ca -
ied ou nea o pH
ZPC
; he e o e, adso p ion o he ions we e no s ud-
ied a pH ˃5.5. As i is indica ed in Fig. 8, he adso p ion e ficiency o he
ions a pH = 1.5 is ze o ha indica es a highly acidic solu ion s ongly
a ec s he ions adso p ion. A acidic solu ion, H
+
concen a ion and
i s mobili ya e high ha lead o s ong compe i ion wi h he ions o oc-
cupy he ac i e si es. Ac ually, he p o ona ion o he ac i e si es occu s
in a low alue o pH, leading o elec os a ic epulsion be ween posi-
i ely cha ged ca ions and posi i ely cha ged ac i e si es; he e o e,
he alue o adso p ion e ficiency is low. As he pH o solu ion inc eases,
he amoun o H
+
being a ailable in he solu iondec eases; hence, mo e
nega i ely cha ged si es a e a ailable ha acili a e highe up ake o he
ions by elec os a ic a ac ion [30]. Acco ding o he ob ained esul s,
u he adso p ion s udies we e pe o med a pH = 5.5 as an op imum
alue.
Fig. 3. FT-IR spec a o (A) CA, (B) CMC, (C) Ni
0.2
Zn
0.2
Fe
2.6
O
4
,and(D)CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
942 H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953
condi ions gi en by CCD was compa ed wi h he alue p edic ed by
RSM. As can be obse ed om he ob ained esul s p esen ed in
Table 3, di e ence be ween he alues ob ained om he expe imen s
and p edic ed by he model esul s in e o pe cen age in he ange o
0.54–1.87, 0.58–2.28, and 0.61–2.11% o Nd (III), Tb (III), and Dy (III),
espec i ely. A pH = 5.5, headso p ione ficiencyunde hecondi ions
gi en by he model (adso ben dosage = 0.1 g, con ac ime = 53 min,
and ini ial concen a ion = 30 mg/L) was calcula ed o be 95.72, 96.17,
and 99.44% wi h 1.17, 0.58, and 0.61% e o o Nd (III), Tb (III), and Dy
(III), espec i ely, indica ing i s ag eemen wi h he expe imen al alue.
The e o s show he capabili y o he RSM model o he p edic ion o
alues ha a e a o ably in acco dance wi h he expe imen al da a.
3.6. Ba ch adso p ion kine ic s udies
Kine ic in es iga ions we e ca ied ou using he solu ions wi h he
olume o 50 mL p epa ed a 30 mg/L o Nd (III), Tb (III), and Dy (III)
ions ha we e con ac ed wi h 0.09 g o he adso ben a a ious imes.
Non-linea pseudo-fi s -o de (PFO), PSO, and in a-pa icle di usion
(IPD) models we e applied o model he kine ic da a o Nd (III), Tb
(III), and Dy (III) ions adso p ion. The equa ions a e as ollows [36,37]:
q ¼qe1−exp:−K1

PFO ð16Þ
q ¼K2qe2 =1þK2qe PSO ð17Þ
q ¼Ki 0:5þCIPD ð18Þ
whe e K
1
(1/min), K
2
(g/mg min), and K
i
(1/min) espec i ely e e o
he PFO a e cons an , PSO a e cons an , and he a e cons an o IPD.
Mo eo e , C p o ides in o ma ion abou he hickness o he bounda y
laye : highe alue o C is ela ed o he bounda y laye di usion
influence.
The ini ial a e o adso p ion (h) can be compu ed using K
2
and q
e
alues by he ollowing equa ion:
h¼K2qe2ð19Þ
The alues o kine ic pa ame e s a e shown in Table 4.Asi isob i-
ous om he esul s, he highes alues o R
2
and he lowes alues o
χ
2
ob ained by PSO shows ha he main mechanism o con olling
he adso p ion o Nd (III), Tb (III), and Dy (III) ions on o he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
is chemiso p ion. The alues o R
2
ob ained by IPD
model show ha he adso p ion o he ions is a mul i-s age p ocess.
The s ages we e ela ed o he s ong elec os a ic o ces o a ac ions
be ween he ions and he unc ional g oups o he adso ben , and g ad-
ualadso p ion by heionsdi usion in o he po eso he adso ben un il
he occupa ion o mos o all o he ac i e si es. In addi ion, IPD model
was no he sole a e-limi ing s ep ( he ela ed plo s do no pass
h ough he o igin).
3.7. Ba ch adso p ion iso he m s udies
Ba ch iso he m expe imen s we e pe o med using 50 mL o
me al ions solu ions a di e en concen a ions in he ange o
30–180 mg/L con ac ing wi h 0.09 g o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
a pH = 5.5. The da a ob ained a equilib ium we e modeled by
Langmui and F eundlich models ha a e espec i ely ela ed o
monolaye and mul ilaye adso p ion. The nonlinea Langmui and
F eundlich models we e used acco ding o ollowing equa ions
[38,39]:
qe ¼bqmCe
1þbCeðÞ
Langmui ð20Þ
qe¼KC
e1=nF eundlich ð21Þ
whe e q
e
and q
m
(mg/g) espec i ely e e o he equilib ium ad-
so p ion and maximum adso p ion capaci ies, and C
e
(mg/L) shows
he adso ba e equilib ium concen a ion. Mo eo e , b (L/mg) and K
(mg
1–1/n
L
1/n
/g) espec i ely e e o Langmui and F eundlich con-
s an s, and n shows adso p ion in ensi y. Adso p ion is a o able i
nN1.
The coe ficien o de e mina ion (R [2]) alues and he co e-
sponding pa ame e s ob ained by he models a e p esen ed in
Table 5. The n alues a e 9, 9.26, and 9.71 o Nd (III), Tb (III), and
Dy (III), espec i ely, showing a s ong in e ac ion be ween he CA/
CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
and he me al ions. Acco ding o he alues
o R
2
and χ
2
, i is ob ious ha F eundlich model be e fi s he expe -
imen al da a han Langmui model o Nd (III), Tb (III), and Dy (III)
ions adso p ion. Consequen ly, he adso p ion o he ions is mul i-
laye adso p ion, and he adso p ion akes place on a non-uni o m
su ace.
3.8. Ionic s eng h e ec
The ions adso p ion can be a ec ed by he co-ions ha a e a ail-
able in he solu ion. The influence o sal concen a ion, known as
ionic s eng h, on he adso p ion e ficiency o he ions by he CA/
Table 4
Kine ic cons an s o adso p ion o Nd (III), Tb (III), and Dy (III) by he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
Nd (III) Tb (III) Dy (III)
PFO K
1
(1/min) 0.2905 0.290 0.289
q
e
(mg/g) 15.07 15.30 15.61
R
2
0.9617 0.9585 0.9587
χ
2
0.240 0.268 0.279
PSO K
2
(g/mg min) × 10
2
2.99 2.93 2.86
q
e
(mg/g) 16.15 16.40 16.74
h (mg/g min) × 10
–2s
7.79 7.88 8.01
R
2
0.9927 0.9933 0.9929
χ
2
0.045 0.043 0.048
IPD K
i
(1/min) 3.88 3.96 4.05
R
2
0.8157 0.8225 0.8222
χ
2
1.16 1.15 1.20
Table 3
Confi ma ion expe imen s o he ions adso p ion on o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
No. Condi ion Nd (III) Tb (III) Dy (III) E o (%)
Time (min) Adso ben dosage (g) Ini ial concen a ion
(mg/L)
Obse ed P edic ed Obse ed P edic ed Obse ed P edic ed
Nd (III) Tb (III) Dy (III) Nd (III) Tb (III) Dy (III)
1 53 0.1 30 30 30 94.61 95.72 96.73 96.17 98.83 99.44 1.17 0.58 0.61
2 19 0.125 75 45 45 63.12 61.9 68.27 66.71 72.85 71.31 1.93 2.28 2.11
3 36 0.2 90 60 60 87.44 86.97 90.86 89.74 93.73 92.17 0.54 1.23 1.66
4 53 0.275 45 75 45 93.48 95.23 96.18 97 97.54 99.05 1.87 0.85 1.54
949H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953

CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
was e alua ed using NaNO
3
a a ious con-
cen a ions anging om 0.02 o 0.1 M, and he esul s a e p e-
sen ed in Fig. 13A. As i is illus a ed in Fig. 13A, he p esence o
NaNO
3
has a g ea e nega i e e ec on he adso p ion e ficiency o
Nd (III) in compa ison wi h Tb (III) and Dy (III). The adso p ion e fi-
ciency o Nd (III), Tb (III), and Dy (III) espec i ely dec eases om
92.33 o 77.12, 93.91 o 85.6, and 96.25 o 91.43% by an inc ease in
NaNO
3
concen a ion. This phenomenon can be ela ed o he com-
pe i ion be ween he me al ions and sodium ions o he a ailable
ac i e adso p ion si es o he adso ben [40]. In addi ion, he agg e-
ga ion o adso ben could be heigh ened by enhancing ionic
s eng h ha esul s in a dec ease in adso p ion si es o adso ben
[41].
3.9. The modynamic pa ame e s
The modynamic pa ame e s a e conside ed as key ac o s o ealize
heop imalcondi ion andgi e u he in o ma ion ega dingchangesin
inhe en ene ge ic ela ed o adso p ion p ocess. The adso p ion p o-
cess was conduc ed a a ious empe a u es (25, 35, and 45 °C) o ob-
ain ΔS
°
and ΔH
°
alues based on he ollowing equa ion:
LnKd¼ΔS°
R−ΔH°
RT ð22Þ
whe eR,T,andK
d
espec i ely e e o he gas cons an (8.314 J/mol K),
empe a u e (K), and dis ibu ion coe ficien ha was ob ained by he
equa ion as ollowing:
Kd¼qe
Ce
ð23Þ
whe e C
e
e e o he equilib ium concen a ion in he solu ion (mg/L).
ΔH
°
alue o each me al is calcula ed om he slope o Ln K
d
e sus 1/T
plo , and ΔS
°
alue is compu ed om i s in e cep (Fig. 13B). The ΔG
°
alues we e also calcula ed a di e en empe a u es by using he ol-
lowing equa ion:
ΔG°¼−RT Ln Kdð24Þ
Table 6 shows he alues o he modynamic pa ame e s. The ΔG
°
alues o he ions a e posi i e a all empe a u es ha show he p ocess
is non-spon aneous, and he adso p ion o he ions on o he adso ben
equi es addi ional ene gy om an ex e nal sou ce. The lowe alues
o ΔG
°
a highe empe a u es mean ha an inc ease in empe a u e
leads o an inc ease in he endency o spon aneous eac ion. The ΔH
°
alue ˃ze o shows he endo he mic adso p ion o he me al ions, and
he ΔS
°
alue ˃ze o exp esses he inc ease in andomness a he in e -
ace o solid–solu ion du ing he me al ions fixa ion on he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
su ace [39].
3.10. Reusabili y s udies
The syn hesized CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
was u ilized in ou con-
secu i e adso p ion-deso p ion cycles o in es iga e i s eusabili y. Fo
his pu pose, he adso p ion o he ions by he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
was pe o med a ini ial concen a ion = 30 mg/L and pH = 5.5 wi h
0.1 g o he adso ben o 53 min. The ba ch flask con aining he CA/
CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
and 50 mL o 0.2 M HNO
3
as eluen was shaken
o 2 h o deso p ion o he ions loaded on o he adso ben s. Then,
he adso ben was sepa a ed by an ex e nal magne ic field om he
HNO
3
solu ion, and he unc ional g oups we eneu alized by NaOH so-
lu ion. The neu alized CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
was hen used o he
adso p ion o 30 mg/L o he ions in he nex cycle. Nd+3, Tb+3, and
Dy+3 ions we e deso bed om he adso ben > 93, 96, and 97 %,
espec i ely.
The esul s o adso p ion e ficiency in 4 cycles a e shown in Fig. 13C.
Due o he dec ease in he elease o he ions and numbe o ac i e si es
by acid ea men du ing he cycles, he adso p ion e ficiency o Nd
(III), Tb (III), and Dy (III) espec i ely dec eases om 94.18 o 91.64,
96.45 o 94.82, and 98.33 o 97.17%. A e he las cycle, he adso p ion
e ficiency o he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
indica es 2.54, 1.63, and
1.16% lose o Nd (III), Tb (III), and Dy, espec i ely, in compa ison
wi h he fi s cycle. The esul s also indica ed ha he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
emained magne ic du ing he p ocess o adso p ion-
deso p ion. Acco ding o he esul s, he adso ben sui abili y o a p ac-
ical applica ion can be concluded.
3.11. Column mode
Fig. 14A p esen s he Nd (III), Tb (III), and Dy (III) ions adso p ion
b eak h ough cu es ob ained om he fixed-bed column packed wi h
Fig. 13. (A) E ec o ionic s eng h on he adso p ion o Nd (III), Tb (III), and Dy (III), (B) Ln K
d
e sus 1/T o calcula ion o en halpy and en opy changes, and (C) Reusabili y o CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
o adso p ion o he ions.
Table 5
Iso he m cons an s o adso p ion o Nd (III), Tb (III), and Dy (III) by he CA/CMC/
Ni
0.2
Zn
0.2
Fe
2.6
O
4
.
Nd (III) Tb (III) Dy (III)
Langmui b (L/mg) 0.78 0.89 1.27
q
m
(mg/g) 23.15 24.41 25.24
R
2
0.8773 0.9238 0.9125
χ
2
1.62 1.21 1.61
F eundlich K (mg
1–1/n
L
1/n
/g) 14.40 15.46 16.49
n 9 9.26 9.71
R
2
0.9879 0.9654 0.9633
χ
2
0.159 0.55 0.675
950 H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953
he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
. Acco ding o he ob ained esul s, he
b eak h ough and exhaus ion imes ha espec i ely co espond o
C
e
/C
0
= 0.05 and 0.95 a e abou 95 and 410 min o Nd (III), 105 and
430 min o Tb (III), and 120 and 440 min o Dy (III). Exhaus olume
(V
e
) o Nd (III), Tb (III), and Dy (III) is espec i ely 410, 430, and
440 mL.
Fig. 14. (A) Expe imen al da a o he column adso p ion and (B–D) Modeling o he expe imen al da a wi h Thomas and Yan models.
Table 6
E ec o empe a u e on he adso p ion o Nd (III), Tb (III), and Dy (III) a 90 mg/L and he modynamic pa ame e s.
Adso p ion e ficiency (%)
Tempe a u e (°C) Nd (III) Tb (III) Dy (III)
25 44.31 47.14 49.21
35 48.23 50.48 53.45
45 52.64 55.99 58.42
The modynamic pa ame e s
Nd (III) Tb (III) Dy (III)
ΔH
°
(kJ/mol) 13.9 14.76 15.45
ΔS
°
(kJ/mol K) 0.039 0.043 0.046
Tempe a u e (
º
C)
ΔG
°
(kJ/mol) 25 2.022 1.739 1.534
35 1.686 1.408 1.151
45 1.274 0.918 0.655
951H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953
Nonlinea Thomas and Yan models we e u ilized o fi he expe i-
men al da a o he fixed-bed column by Eq. (25) and Eq. (26), espec-
i ely.
C
C0¼1
1þexp KThqex
Q−KThC0
 ð25Þ
C
C0¼1−1
1þC0Q
qex

að26Þ
whe e K
Th
shows he a e cons an (mL/min mg), a is a cons an coe fi-
cien andq
e
is he maximum adso p ioncapaci y(mg/g),xis he mass o
adso ben (g), C
0
is he ini ial concen a ion (mg/L) o he ions, C
is ou -
le ions concen a ion (mg/L), is he con ac ime (min), and Qis he
flow a e (mL/min). K
Th
,a,andq
e
alues a e compu ed using he slope
and in e cep o he plo o C
C0agains .
The pa ame e s ob ained by he models (Figs. 14B-D) a e indica ed
in Table 7. The adso p ion capaci y (q
e
) o Nd (III), Tb (III), and Dy
(III), calcula ed by Eq. (9), is espec i ely 22.70, 24.00, and 25.54 mg/g
unde he s udied condi ions. Acco ding o he alues o R [2], bo h
models can fi he expe imen al da a well bu Yan model p esen s
highe alues o R
2
in compa ison wi h Thomas model. The a e con-
s an alue o Thomas (K
Th
) o Nd (III) is highe han hose o Tb (III),
and Dy (III), showing highe in ensi y o Nd (III) adso p ion on o he
CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
, while he amoun o maximum adso p ion
capaci y (q
e
) o Dy (III) is g ea e han he alue ob ained o Nd (III)
and Tb (III). This is in con o mi y wi h he esul s achie ed om expe -
imen s o ba ch adso p ion.
4. Conclusion
In his pape , he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
was syn hesized success-
ully by he gela ion p ocess o CA/CMC in he p esence o he
Ni
0.2
Zn
0.2
Fe
2.6
O
4
. RSM-CCD was applied o explo e he influences o ex-
pe imen al pa ame e s on Nd (III), Tb (III), and Dy (III) ions adso p ion.
The condi ions p edic ed by RSM o op imum adso p ion o 30 mg/L o
he ions we e 0.1 g o he adso ben and 53 min con ac ime a pH =
5.5. The expe imen al da a we e fi ed by iso he m and kine ic models.
PSO kine ic model fi ed he da a be e compa ed wi h IPD and PFO
models. The da a o equilib ium we e fi ed well wi h F eundlich
model. The alues o ΔH
°
e ealed he endo he mic adso p ion p ocess
o he me al ions. 0.2 M HNO
3
was used o egene a ion o he ion-
loaded adso ben , and he adso ben was epea edly used in ou cycles
wi h N91, 94, and 97% adso p ion e ficiency o Nd (III), Tb (III), and Dy
(III), espec i ely, a e he ou h cycle. Besides, he ions we e success-
ully adso bed in a con inuous p ocess by applying a packed-bed col-
umn, and he da a we e ound o be fi ed well by Thomas and Yan
models. The esul s showed ha he CA/CMC/Ni
0.2
Zn
0.2
Fe
2.6
O
4
can be
applied as a po en ial adso ben in bo h adso p ion modes (ba ch and
column) o Nd (III), Tb (III), and Dy (III) ions adso p ion.
CRediT au ho ship con ibu ion s a emen
Hamed eza Ja adian: In es iga ion, Da a cu a ion, Fo mal analysis,
W i ing - o iginal d a , W i ing - e iew & edi ing. Mon se a Ruiz:
Da a cu a ion, Supe ision. Ana Ma ia Sas e: Concep ualiza ion,
Supe ision.
Acknowledgmen s
This wo k has been suppo ed by he Spanish Minis y o Economy
and Compe i i eness (Re . CTM2017-83581-R).Hamed ezaJa adianac-
knowledges he financial suppo ecei ed (Re . BES-2015-072506).
Re e ences
[1] G.A. Moldo eanu, V.G. Papangelakis, Reco e y o a e ea h elemen s adso bed on
clay mine als. I. Deso p ion mechanism, Hyd ome allu gy 117–118 (2012) 71–78.
[2] J. Ponou, L.P. Wang, G. Dodbiba, K. Okaya, T. Fuji a, K. Mi suhashi, T. A a ashi, G.
Sa oh, M. Noda, Reco e y o a e ea h elemen s om aqueous solu ion ob ained
om Vie namese clay mine als using d ied and ca bonized pa achlo ella, J. En i on.
Chem. Eng. 2 (2014) 1070–1081.
[3] W. F anus, M.M. Wia os-Mo yka, M. Wdowin, Coal fly ash as a esou ce o a e
ea h elemen s, En i on. Sci. Pollu . Res. 22 (12) (2015) 9464–9474.
[4] D. Sado sky, A. B enne , B. As achan, B. Asa , R. Gonen, Bioso p ion po en ial o ce-
ium ions using Spi ulina biomass, J. Ra e Ea hs 34 (2016) 644–652.
[5] F. Zhao, E. Repo, Y. Meng, X. Wang, D. Yin,M. Sillanpää, An EDTA-β-cyclodex in ma-
e ial o he adso p ion o a e ea h elemen s and i s applica ion in
p econcen a ion o a e ea h elemen s in seawa e , J. Colloid In e ace Sci. 465
(2016) 215–224.
[6] K. Vijaya agha an, R. Balasub amanian, Single and bina y bioso p ion o ce ium and
eu opium on o c ab shell pa icles, Chem. Eng. J. 163 (2010) 337–343.
[7] J.L. Wang, C. Chen, Bioso ben s o hea y me als emo al and hei u u e,
Bio echnol. Ad . 27 (2) (2009) 195–226.
[8] H.A. Shawky, Imp o emen o wa e quali y using algina e/mon mo illoni e com-
posi e beads, J. Appl. Polym. Sci. 119 (4) (2010) 2371–2378.
[9] Y. Ma, P. Qi, J. Ju, Q. Wang, L. Hao, R. Wang, K. Sui, Y. Tan, Gela in/algina e composi e
nanofibe memb anes o e ec i e and e en adso p ion o ca ionic dyes, Compos
Pa B Eng 162 (2019) 671–677.
[10] F. Ahmadpoo , S.A. Shojaosada i, S.Z. Mousa i, Magne ic silica coa ed i on ca bide/
algina e beads: syn hesis and applica ion o adso p ion o cu (II) om aqueous so-
lu ions, In . J. Biol. Mac omol. 128 (2019) 941–947.
[11] T. Guo, Y. Pei, K. Tang, X. He, J. Huang, F. Wang, Mechanical and d ug elease p op-
e ies o algina e beads ein o ced wi h cellulose, J. Appl. Polym. Sci. 134 (8) (2016)
44495.
[12] Z.H. Hu, A.M. Ome , X.K. Ouyang, D. Yu, Fab ica ion o ca boxyla ed cellulose nano-
c ys al/sodium algina e hyd ogel beads o adso p ion o Pb(II) om aqueous solu-
ion, In . J. Biol. Mac omol. 108 (2018) 149–157.
[13] R. Ahmad, A. Mi za, Adso p ion o Pb (II) and cu (II) by algina e-au-mica
bionanocomposi e: kine ic, iso he m and he modynamic s udies, P ocess Sa En i-
on 109 (2017) 1–10.
[14] L. Zhang, Y. Zeng, Z. Cheng, Remo al o hea y me al ions using chi osan and modi-
fied chi osan: a e iew, J. Mol. Liq. 214 (2016) 175–191.
[15] M. Li, J. Xu, R. Li, D. Wang, T. Li, M. Yuan, J. Wang, Simple p epa a ion o
amino hiou ea-modified chi osan as co osion inhibi o and hea y me al ion adso -
ben , J. Colloid In e ace Sci. 417 (3) (2014) 131–136.
[16] D.W. Cho, B.H. Jeon, C.M. Chon, Y. Kim, F.W. Schwa z, E.S. Lee, H. Song, A no el chi-
osan/clay/magne i e composi e o adso p ion o cu(II) and as(V), Chem. Eng. J.
200–202 (34) (2012) 654–662.
[17] L. Fan, C. Luo, Z. L , F. Lu, H. Qiu, Remo al o Ag
+
om wa e en i onmen using a
no el magne ic hiou ea-chi osan imp in ed Ag
+
, J. Haza d. Ma e . 194 (11)
(2011) 193–201.
[18] P.O. Boamah, Y. Huang, M. Hua, Q. Zhang, J. Wu, J. Onumah, L.K. Sam-Amoah, P.O.
Boamah, So p ion o hea y me al ions on o ca boxyla e chi osan de i a i es—a
mini- e iew, Eco oxicol. En i on. Sa . 116 (2015) 113–120.
[19] H. Yang, H. Li, J. Zhai, L. Sun, Y. Zhao, H. Yu, Magne ic p ussian blue/g aphene oxide
nanocomposi es caged in calcium algina e mic obeads o elimina ion o cesium
ions om wa e and soil, Chem. Eng. J. 246 (2014) 10–19.
[20] G. Reiss, A. Hü en, Magne ic nanopa icles: applica ions beyond da a s o age, Na .
Ma e . 4 (2005) 725–726.
Table 7
Pa ame e s o b eak h ough and he alues p edic ed by Thomas and Yan models.
Me al B eak h ough analysis Thomas model Yan model
q
e
Adso p ion e ficiency (%) C
e
K
Th
×10
4
q
e
R
2
q
e
aR
2
Nd (III) 22.70 46.33 16.10 5.65 22.18 0.9945 21.10 3.74 0.9957
Tb (III) 22.70 47.07 15.88 5.52 23.44 0.9937 22.32 3.83 0.9962
Dy (III) 25.54 49.11 15.26 5.46 24.96 0.9940 23.92 4.01 0.9970
952 H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953
[21] D. Gusain, F. Bux, Y. Chand a Sha ma, Aba emen o ch omium by adso p ion on
nanoc ys alline zi conia using esponse su ace me hodology, J. Mol. Liq. 197
(2014) 131–141.
[22] N. Ma kandeya, S. Dhiman, P. Shukla, G.C. Kisku, S a is ical op imiza ion o p ocess
pa ame e s o emo al o dyes om was ewa e on chi osan cenosphe es nano-
composi e using esponse su ace me hodology, J. Clean. P od. 149 (2017) 597–606.
[23] V. S i as a a, Y.C. Sha ma, M. Sillanpää, Applica ion o esponse su ace me hodol-
ogy o op imiza ion o co(II) emo al om syn he ic was ewa e by adso p ion
on NiO nanopa icles, J. Mol. Liq. 211 (2015) 613–620.
[24] D. Ni, Z. Lin, P. Xiaoling, W. Xinqing, G. Hongliang, P epa a ion and cha ac e iza ion
o nickel-zinc e i es by a sol o he mal me hod, Ra e Me al Ma Eng 44 (9) (2015)
2126–2131.
[25] C. Tamez, R. He nandez, J.G. Pa sons, Remo al o cu (II) and Pb (II) om aqueous so-
lu ion using enginee ed i on oxide nanopa icles, Mic ochem. J. 125 (2016) 97–104.
[26] R. Fab yan y, C. Valencia, F. Edi Soe a edjo, J. Nyoo Pu o, S. Pe ma asa i San oso, A.
Ku niawan, Y.H. Ju, S. Ismadji, Remo al o c ys al iole dye by adso p ion using
ben oni e-algina e composi e, J. En i on. Chem. Eng. 5 (2017) 5677–5687.
[27] S.P. Wu, X.Z. Dai, J.R. Kan, F.D. Shilong, M.Y. Zhu, Fab ica ion o ca boxyme hyl
chi osan–hemicellulose esin o adso p i e emo al o hea y me als om was e-
wa e , Chin. Chem. Le . 28 (2017) 625–632.
[28] A.S.A. Bak , Y.M. Mous a a, E.A. Mo awea, M.M. Yehia, M.M.H. Khalil, Remo al o e -
ous ions om hei aqueous solu ions on o NiFe
2
O
4
–algina e composi e beads, J.
En i on. Chem. Eng. 3 (2015) 1486–1496.
[29] S.A. El eky, S. Eb ahim Mahmoud, A. Fahmy Yousse , Applica ions o CTAB modified
magne ic nanopa icles o emo al o ch omium (VI) om con amina ed wa e , J.
Ad . Res. 8 (4) (2017) 435–443.
[30] R. Da ishi Cheshmeh Sol ani, G. Shams Kho amabadi, A.R. Kha aee, S. Jo fi,Silica
nanopowde s/algina e composi e o adso p ion o lead (II) ions in aqueous solu-
ions, J. Taiwan Ins . Chem. Eng. 45 (2014) 973–980.
[31] R.D.C. Sol ani, A. Rezaee, H. Godini, A.R. Kha aee, A. Hasanbeiki,
Pho oelec ochemical ea men o ammonium using seawa e as a na u al
suppo ing elec oly e, Chem. Ecol. 29 (2013) 72–85.
[32] M. El kady, H. Shok y, H. Hamad, E ec o supe pa amagne ic nanopa icles on he
physicochemical p ope ies o nano hyd oxyapa i e o g oundwa e ea men : ad-
so p ion mechanism o Fe(II) and Mn (II), RSC Ad . 6 (2016) 82244–82259.
[33] A. Mohseni-Bandpi, B. Kaka andi, R.R. Kalan a y, A. Aza i, A. Ke ama i, De elopmen
o a no el magne i e-chi osan composi e o he emo al o fluo ide om d inking
wa e : adso p ion modeling and op imiza ion, RSC Ad . 5 (2015) 73279–73289.
[34] H. Sheka i, M.H. Sayadi, M.R. Rezaei, A. Allah esani, Syn hesis o nickel e i e/ i a-
nium oxide magne ic nanocomposi e and i s use o emo e hexa alen ch omium
om aqueous solu ions, Su . In e ace. 8 (2017) 199–205.
[35] K.S. Padma a hy, G. Madhu, P.V. Haseena, A s udy on e ec s o pH, adso ben dos-
age, ime, ini ial concen a ion and adso p ion iso he m s udy o he emo al o
hexa alen ch omium (C (VI)) om was ewa e by magne i e nanopa icles,
P ocedia Technol 24 (2016) 585–594.
[36] S.C.W. Sak i, Y. Na i a, T. Sasaki, S. Tanaka Nu yono, A no el py idinium unc ional-
ized magne ic chi osan wi h pH-independen and apid adso p ion kine ics o
magne ic sepa a ion o C (VI), J. En i on. Chem. Eng. 3 (2015) 1953–1961.
[37] H. Ja adian, P. Vahedian, M. Toosi, Adso p ion cha ac e is ics o Ni(II) om aqueous
solu ion and indus ial was ewa e on o Polyaniline/HMS nanocomposi e powde ,
Appl. Su . Sci. 284 (2013) 13–22.
[38] V.S. Munagapa i, D.S. Kim, Equilib ium iso he ms, kine ics, and he modynamics
s udies o Congo ed adso p ion using calcium algina e beads imp egna ed wi h
nano-goe hi e, Eco oxicol. En i on. Sa . 141 (2017) 226–234.
[39] H. Ja adian, M. To abi Angaji, M. Naushad, Syn hesis and cha ac e iza ion o
polyaniline/γ-alumina nanocomposi e: a compa a i e s udy o he adso p ion o
h ee di e en anionic dyes, J. Ind. Eng. Chem. 20 (2014) 3890–3900.
[40] S. Malamis, E. Ka sou, A e iew on zinc and nickel adso p ion on na u al and mod-
ified zeoli e, ben oni e and e miculi e: examina ion o p ocess pa ame e s, kine ics
and iso he ms, J. Haza d. Ma e . 252 (2013) 428–461.
[41] F.F. Zeng, Y. He, Z.H. Lian, J.M. Xu, The impac o solu ion chemis y o elec oly e on
he so p ion o pen achlo ophenol and phenan h ene by na u al hema i e nanopa -
icles, Sci. To al En i on. 466 (2014) 577–585.
953H. Ja adian e al. / In e na ional Jou nal o Biological Mac omolecules 154 (2020) 937–953
137

138
ANNEX III
Syn hesis o magne ic CMC bionanocomposi e con aining a no el biodeg adable nanopo ous
polyamide selec i ely syn hesized in ionic liquid as g een media: In es iga ion on Nd+3,
Tb+3, and Dy+3 a e ea hs adso p ion.
Hamed eza Ja adian, Mon se a Ruiz, Mehdi Tagha i, Ana Ma ia Sas e,
Jou nal o Molecula Liquids, 308 (2020) 113017.
h ps://doi.o g/10.1016/j.molliq.2020.113017
139
Syn hesis o magne ic CMC bionanocomposi e con aining a no el
biodeg adable nanopo ous polyamide selec i ely syn hesized in ionic
liquid as g een media: In es iga ion on Nd
+3
,Tb
+3
,andDy
+3
a e ea h
elemen s adso p ion
Hamed eza Ja adian
a,
⁎,Mon se a Ruiz
b
, Mehdi Tagha i
c
, Ana Ma ia Sas e
a
a
Depa men o Chemical Enginee ing, ETSEIB, Uni e si a Poli ècnica de Ca alunya, Diagonal 647, 08028 Ba celona, Spain
b
Depa men o Chemical Enginee ing, EPSEVG, Uni e si a Poli ècnica de Ca alunya, A . Víc o Balague , s/n, 08800 Vilano a i la Gel ú, Spain
c
Depa men o Chemis y, Facul y o Science, Shahid Cham an Uni e si y o Ah az, 61357-43337, I an
abs ac a icle in o
A icle his o y:
Recei ed 27 Oc obe 2019
Recei ed in e ised o m 20 Ma ch 2020
Accep ed 28 Ma ch 2020
A ailable online 31 Ma ch 2020
Keywo ds:
Ca boxyme hyl chi osan
Poly(py imidine- hiophene-amide)
Magne ic
Bionanocomposi e
Adso p ion
Ra e ea h elemen s
In his esea ch s udy, he ca boxyme hyl chi osan/poly(py imidine- hiophene-amide)/Ni
0.2
Zn
0.2
Fe
2.6
O
4
(CMC/P
(PTA)/Ni
0.2
Zn
0.2
Fe
2.6
O
4
) was p epa ed as a no el magne ic bionanocomposi e adso ben . FE-SEM, EDX, NMR,
XRD, FT-IR, and VSM echniques we e applied o he analyses o he p oduc s. The adso p ion beha io o he
p epa ed bionanocomposi e was in es iga ed owa ds Nd
+3
,Tb
+3
,andDy
+3
as adso ba es. The adso p ion p o-
cess was e alua ed conside ing he influence o independen pa ame e s including pH o he solu ion, con ac
ime, adso ben dosage, ini ial me al ions concen a ion, and ionic s eng h. The adso p ion e ficiency alues o
98.15, 97.6, and 99.42% we e espec i ely ob ained o Nd
+3
,Tb
+3
, and Dy
+3
a op imum condi ions o pH =
5.5, 30 mg/L o he ions, adso ben dosage o 0.06 g, and con ac ime o 90 min. The da a o he adso p ion equi-
lib ium o he ions we e fi ed well by F eundlich model. Kine ic s udies showed ha Nd
+3
,Tb
+3
,andDy
+3
ad-
so p ion ollowed bo h pseudo-second-o de (PSO) and in a-pa icle di usion (IPD) kine ic models. The alues
o ΔH
°
indica ed ha he ions adso p ion p ocess on o he bionanocomposi e was endo he mic, and he ΔG
°
alues e ealed ha i was spon aneous a highe empe a u e. The CMC/P(PTA)/Ni
0.2
Zn
0.2
Fe
2.6
O
4
could be e-
gene a ed by 0.2 M HNO
3
and i s sepa a ion was iable u ilizing a magne ic field wi h he sa u a ion magne iza-
ion alue o 14.88 emu/g.
© 2020 Published by Else ie B.V.
1. In oduc ion
Ra e ea h elemen s (REEs) con ain 17 componen s o he pe iodic
able ha include 15 lan hanides oge he wi h y ium and scandium
[1–3]. Ligh and hea y REEs a e he addi ional subdi ision o REEs
based on a omic numbe . They possess excep ional p ope ies and a e
egula ly named as “seeds o echnology”[4]. They a e ex ensi ely u i-
lized in a ious fields, o example, elec onics, me allu gy, ca alysis, al-
loys, supe conduc o s, lase s, e ilize s, chemical eagen s, nuclea
ene gy, and magne s [5,6]. The o al demand o REEs was epo ed
128,000 ons in 2011, and his amoun was aised up o 170,000 ons
in 2015. I is also an icipa ed ha i would inc ease up o 255,000 ons
in 2020 wi h a ound 6–10%/yea g ow h a e [7]. This an icipa ed
la ge demand o REEs is as a esul o hei b oad usage in nume ous
fields o human li e.Acco ding o his ma e , hei eco e y om was es
seems o be necessa y. Di e en echniques, such as p ecipi a ion, ion
exchange, sol en ex ac ion, and adso p ion ha e been u ilized o
REEs eco e y om aqueous media [8–11]. Nume ous in es iga ions
ha e shown adso p ion as a high-e ficien , cos -e ec i e and simple
echnique o REEs eco e y om aqueous media amongs he physico-
chemical ea men echniques.
Chi osan is a de i a ion o chi in, a na u al polysaccha ide ha com-
p ises β(1–4)-2-amino-2-deoxy-D-glucan uni s and possesses supe b ad-
so p ion pe o mance o me al ions, chiefly owing o con aining a la ge
amoun o amino and hyd oxyl g oups [12]. I s s uc u e is like a c ys al
wi h hyd ogen bonds. None heless, he p o ona ion o he amino g oups
in he acidic medium leads o losing s uc u al s eng h by he o ma ion
o a gel-like solu ion ha esul s in significan es ic ions o i s applica-
ions [13]. So as o sol e his issue, he modifica ion o chi osan has been
ca ied ou by sul ona ion, ni a ion, hyd oxyalkyla ion, qua e na iza ion,
hyd oxyla ion, polye hyleneglycol-g a ing, ca boxyme hyla ion, and so
on [14,15]. Amongs he de i a i es o chi osan, ca boxyme hyl chi osan
Jou nal o Molecula Liquids 308 (2020) 113017
⁎Co esponding au ho .
E-mail add ess: Hamed eza.ja [email protected] (H. Ja adian).
h ps://doi.o g/10.1016/j.molliq.2020.113017
0167-7322/© 2020 Published by Else ie B.V.
Con en s lis s a ailable a ScienceDi ec
Jou nal o Molecula Liquids
jou nal homepage: www.else ie .com/loca e/molliq
(CMC) is an ampho e ic e he de i a i e ha each molecule comp ises
heac i eg oupso COOH, OH, and NH
2
. The ca boxyme hyla ion
o chi osan causes i o be dissol ed in wa e . Thus, he p oblem ela ed o
losing he s uc u al s abili y ha akes place by NH
2
p o ona ion in he
acidic medium can be sol ed [16]. In addi ion, ca boxyl g oups a e able o
inc ease me al ions adso p ion [17]. Whe eas chi osan is a na u al poly-
me , i s de i a i es like CMC also ha e some ad an ages such as being bio-
compa ible and low oxic.
Recen ly, nume ous polycondensa ion eac ions ha e been con-
duc ed in ionic liquids (ILs) a oom empe a u e (RT) as a subs i u e
o se e al ola ile oxic sol en s [18]. In indus y, i is necessa y o sub-
s i u e a g ea numbe o o ganic sol en s wi h en i onmen ally, non-
ola ile and g een sol en s o p epa ing high molecula weigh
polyme s. The a ac ion o ambien empe a u e imidazolium based
ILs o subs an ial comme cial p oduc ions and applica ions as sol en s
and ca alys s in polyme iza ion, ex ac ion, and as al e na i es o o di-
na y ola ile o ganic sol en s has been confi med. Re iewing he ILs ap-
plica ion in polyme ab ica ion e ifies hei pe o mance.
Consequen ly, di e en p ocesses o polycondensa ion in he ionic me-
dium ha e been e ec i ely conduc ed [19].
In ecen yea s, inc easing a en ion in he s udies o syn he ic
polyme -polyme composi es owing o he unique combina ion o
beneficial p ope ies and cons uc ion o mul i unc ional s uc u es
o each componen has been epo ed. These composi es display po-
en ially g ea e he mal, mechanical, and elec ical p ope ies han
heuniquepolyme [20]. Syn he ic PAs a e gene ally known as he
fi s enginee ing plas ics and a e s ill conside ed as one o he bes
and mos p ominen classes o hese ypes o ma e ials. Hence,
hese polyme s in oduc ion in he na u al polyme s chemical s uc-
u es is able o supply enhanced p ope ies o indi idual usages, o
which polyme ha ing hese sequences ha e shown inc edibly ex-
cellen p ope ies [21].
In his s udy, CMC, a no el biodeg adable nanopo ous polyamide
(poly(py imidine- hiophene-amide)) syn hesized by polycondensa ion
eac ion o 5,5′-( hiophen-2-ylme hylene)bis(2-aminopy imidine-4,6-
diol) (TMAPD) wi h e eph halic acid in 1,3-dip opyl imidazolium b o-
mide {[1,3-(p )
2
im]B } ionic liquid as g een media, and he hyd o he -
mally syn hesized Ni
0.2
Zn
0.2
Fe
2.6
O
4
we e applied o p oduce a no el
bionanocomposi e (CMC/P(PTA)/Ni
0.2
Zn
0.2
Fe
2.6
O
4
) by he gela ion p o-
cess. FE-SEM, EDX, NMR, XRD, FT-IR, and VSM we e u ilized o confi m
he ab ica ion o he p oduc s. In he ollowing, i was used as an adso -
ben o in es iga e i s e ec i eness o Nd
+3
,Tb
+3
,andDy
+3
ions ad-
so p ion. The influences o di e en ac o s including solu ion pH,
con ac ime, adso ben dosage, ini ial me al ions concen a ion, and
ionic s eng hon he adso p ion e ficiency we e conside ed.The models
o adso p ion kine ic and iso he m we e employed o each he bes
fi ing o he expe imen al da a. The eusabili y o he adso ben was
also in es iga ed.
2. Ma e ials and me hods
2.1. Ma e ials and eagen s
Ca boxyme hyl chi osan was pu chased om Nan ong Chem-Base
Co, China. Dy(NO
3
)·5H
2
O was pu chased om Al a Aesa . Nd(NO
3
)
3
·6H
2
O, Tb(NO
3
)
3
·6H
2
O, Zn(NO
3
)
2
·6H
2
O, Fe(NO
3
)
3
·9H
2
O, Ni(NO
3
)
2
·6H
2
O, glu a aldehyde, 2-amino-4,6-dihyd oxypy imidine, 2-
hiopheneca boxaldehyde, e eph halic acid, iphenyl phosphi e
(TPP), dime hyl sul oxide (DMSO), and me hanol we e bough om
Sigma-Ald ich. All chemicals chosen in his s udy we e a analy ical
g ade and we e u ilized as ecei ed wi hou u he pu ifica ion.Theex-
pe imen solu ions o Nd
+3
,Tb
+3
,andDy
+3
ions we e made by he di-
lu ion o 1000 mg/L o ions. To adjus he ini ial alue o pH in he es
solu ions o he desi ed alue, app op ia e mola i y o HNO
3
o NaOH
was used.
2.2. Ins umen a ion and cha ac e iza ion
The XRD pa e n was eco ded by an X- ay di ac ome e (GBC
MMA), and he samples we e scanned om 2θ= 10° o 70°. A spec o-
pho ome e (Pe kinElme , USA) was also used o eco d FT-IR spec a.
B uke Ad ance DRX was employed o eco d
1
HNMRand
13
CNMR
spec a a 400 MHz and 100MHz, espec i ely, by DMSO‑d
6
as a sol en .
The ni ogen adso p ion-deso p ion iso he m was measu ed a
−196 °C using a Mic ome i ics T is a 3000 appa a us. The mo phology
o he p oduc s was explo ed by a FE-SEM (Zeiss Neon-40, Ge many).
TGA measu emen s we e pe o med by Me le TGA/SDTA 851e/LF/
1100 he mobalance unde he a mosphe e o N
2
om RT o 1000 °C
wi h a a e o 10 °C/min. Magne ic measu emen s we e done using a i-
b a ing sample magne ome e (VSM, Daghigh Ka i Co po a ion, I an).
Fo analyzing he concen a ion o Nd
+3
,Tb
+3
,andDy
+3
, an Agilen
4100 MP-AES Spec ome e was used.
2.3. Syn hesis o he Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic nanopa icles
The Ni
0.2
Zn
0.2
Fe
2.6
O
4
magne ic nanopa icles we e syn hesized by
he hyd o he mal me hod. A mixed solu ion o 0.2 M Ni
2+
,0.2M
Zn
2+
,and2.6MFe
3+
was p epa ed in HCl solu ion, and hen NaOH so-
lu ion was added in o he mixed solu ion unde ni ogen gas, and he
mix u e pH alue was se o 10.5. 0.3 g o CTAB was added o his mix-
u e, and hen i was placed in o an au ocla e (Teflon-lined s ainless
s eel) a 200 °C o an o en. A e 8 h o hyd o he mal ea men , he
empe a u e o he au ocla e was na u ally dec eased o RT, and he
p ecipi a e was collec ed and washed se e al imes wi h deionized
wa e (DW) o each neu al pH. Finally, he ob ained pa icles we e
d ied a 50 °C.
2.4. Syn hesis o he ionic liquid (1,3-dip opyl imidazolium b omide) and
he monome (5,5′-( hiophen-2-ylme hylene)bis(2-aminopy imidine-
4,6-diol (TMAPD))
The RT ionic liquid (IL) was syn hesized based on he p ocess p e-
sen ed in he li e a u e [22]. TMAPD was syn hesized acco ding o he
ollowing p ocedu e: A mix u e o 2.54 g (0.02 mol) 2-amino-4,6-
dihyd oxypy imidine, 1 mL (0.01 mol) 2- hiopheneca boxaldehyde,
and 20 mL DMSO was s i ed o 6 h a 110 °C. A e comple ion o he
eac ion es ed by hin-laye ch oma og aphy, he empe a u e o he
solu ion was dec eased o RT, and he iole powde ob ained by
pou ing he solu ion in o 400 mL o cold DW (−5°C)wasfil e ed,
insed se e al imes using DW and hen d ied using acuum o en a
100°C. The eac ion yield was 92% (3.20g), and he ob ained compound
has no shown sha p mel ing poin and s a ed obe decomposed abo e
300 °C. FT-IR (KB , cm
−1
): 3153–3477 (s e ching o O H and NH
2
),
3049 (s e ching o C H a oma ic), 2944 (s e ching o C Halipha ic),
1651 (s e ching o C_N), 1586 (s e ching o C_C), 1232 (C N) and
1163 (C O).
1
H NMR (DMSO‑d
6
,δin ppm) (Fig. 1): 5.33 (s, 1H, CH),
6.61 (s, 4H, NH
2
), 6.78–6.80 (d, 1H, A H, J= 5.6 Hz), 6.93–6.94
(d, 1H, A H, J= 5.6 Hz), 7.42–7.44 (d, 1H, A H, J=5.2Hz),
10.95–11.28 (m, 4H, b oad, hyd oxy py imidine).
13
C NMR (100 MHz,
DMSO‑d
6
,δin ppm) (Fig. 2): 30.98, 115.41, 128.27, 128.55, 137.86,
140.13, 143.76, 170.77.
2.5. Syn hesis o he biodeg adable nanopo ous P(PTA) by polycondensa-
ion eac ion o TMAPD in TPP/IL
The syn hesis o he biodeg adable nanopo ous P(PTA) was ca ied
ou om a compound con aining mul i pola hiophene, amine, and
ee hyd oxyl chela ing g oups. I was pa icula ly syn hesized om
he diamine-phenol compound in 1,3-dip opyl imidazolium b omide
as an ionic liquid wi hou using oxic iphenyl phosphi e/N-
me hylpy olidone/py idine/LiCl ha is needed in he o dina y di ec
polycondensa ion. The P(PTA) was achie ed by polycondensa ion o
2H. Ja adian e al. / Jou nal o Molecula Liquids 308 (2020) 113017