+
--
Faailty o_l'h{atlwtriarir-s Ltt id l{Grltro I Scict'lccs
Scho<-t/of Lqfe Scintals ,rrtd T't'c/tnolon.1,
Scltooi o[' P h tt r-trt,-tt"-V
Ilsti ft tt lTt:krttlk.! i Ilt ndu n.q
ffil
!uA.V
_6.l\
E
\J7
I r r f c r - * r r : ' : r : r ?t x i C c t t f r : r e w c e c n
M atherF:6?{ r,'', i etwi.,Vrifu.'dEI Sciences
;
.;l-
irl
, . ' f i l. M
'{
:$/*
7l
/r
Ih
|
ttf.\
A
A
fi,
I
t-t
.AAG6
iSBr.j ; 979-*?507 -9 1-B
FENiES,ilr.",N
TELAI] T)IPERIKSA
KEFI;,AP.',N'.''
Dt N SESUAI
9ENGANA3-[..]':;.
I n t e m : r t i o n aC
l o n f c r e n s co n \ ' l a t h e m a t i c sa n d N a t u r a l S c i c n c c s{ l ( ' V N S I
Novembcr 29-.30.2006. Bandung-lnderncsia
Study of Reaction Mechanismson the Adsorption of
9-Aminoacridine by N{ontmorillonite
'
Jaslin Ikhssn', Endang ll'idjajanti LF'(, Sunafiol
Fut'ult.t'ol ,I[uthemutic'sunrl Nuturulscicnc'r's. I'og.tukurtuStcte Ltniver.titt'
Delxtrtment ol Chcnti.stt.r',
Ka ru ngntulung, l' og1'aka rta, 552I I
Abstract
De.tpite the utlsorpttion o/ 9-utninouc'ridine (9-AAl to t'lcry minerul montntorillonile hu-s lteen
inrestiguted previousl.t'. thc rt'ttttion mechunisnts ol the udsorption ure still intereslirtg to studl . Thi.\
reseurt.h tries to dest'rihe the interut'tion betv'e(.|t9-.1.1.untl sutlitt'e.site.sol montmtn'illonite h.t modt'ling
motlels tEC'C'.lI.sl.
e.rperimentultlutu u,singuil arten(le(lcoil-rtuntcdput'it1B*e su/ut'e <'ontTtlexulion
meustred ut 30"C u'ith 5 m,\t r(\'O, a.r'
mwffiiiltonite,gtts
,ldutrlttitttt o/ 9-,1A oil K-.\untrutted
|hehtr,kgnt.ttt,l,,lec,tr,ll1,te.Three|']:e'solurLstlrptitln,,puf,.,,,,,,.uciti-buseri|ru|itlns'
IFTIR) unrl ,Y-Ru.t'Dilli'utrion
tntl udsrtrptiott i;;otht,rnt.srere t'urrie$#fi. Fouricr Trunslnn*#i'ared
(.YRD) meusureneills rrcre ulso cr-tntlut:lcdlo utnfirnt ECC'lls results. g,'r*{
ECC,lls ro tha dutlgsglrtthe udxtrptitttt t'.rperintents und l:'flR ddtu#ei..\tlgges!!ltut dt lo$
('on('ciltrution.sthe 9-AA.li.u'nt'iiuter-.sphere
.lOll sita.srtrr
surJttc't'Lrntttlexeswith plt- iepenTfEirl.r'clutrgerd
the t.lgt' rtl ntuttttttttrillr,uitethrough htdroge"nbonding, unLl xitlt pernlunent- n(,grrlil'c'{$#f4rlglrl.silc'.st.\'-l
'i,'
shupetl ut
rttt thr'.tilictt-like.ltttffif tltc (lur ria rutiii ex(huilge mechunism.s.Arlsrtrptitn i.sotlrrms urt
's'agf4aped
pll 1.() und
ut pll 6 0. At pll 6.{). esiteciall,v,the isothe:nnsiutlit'ute u urrtperutir.,t'uds()t't)ti(,tl
met,|rnisnQ.'Ihecon(eitru|io|l.\rl|thenolecule!fC|.gdstrtle.:iutse"inq.eusingthe('()|l('e|1|r(t!iL|
night m,,dif"r.the t'lur tctntuke binding ,timaiet:ules tt,ith the surfact: ntrtre litv>rul';le..YRDdutd tiiggc.\tthut
.ton)tioil occur.\ ilot onlr ut e.rlt'rnul-Y- silgs bu! olso ai those in the inte'rlarcr .\puce.t.
tc*tpletaiion mrxlel: a.rtcndt'tlton.slan!
KeyWOfdS : nttntntorillonite; 9-,lminoart'lCiue; .sttr.litce
t u p u t i t * n c em o d e l
I. Introduction
lVloutmorillonitc crl,stals li*ve
trl4)
diflcrcnt regions n'hich havc bccn implicated in
adsorption.i), l). Thc cxtcrnal rcgior.tsiiaces p_lus
cdgcs) carl' both pemranent ncgativelv chargcd
FTIR nreasurements. This rcsearch conrbincs
adsorption,FTIR spcctroscopic.XRD and surtacc
'cornpleration modcling invcstigationsto dcducc
the nu-rde qi intcraction beht cen 9-AA and
nrcntmorilIonite.
{{. ExperirnentalMethods
chatgei;
1.Y-)sites and sites u'ith pH-depcndrut
*&1ai{i'iif;:*..-*t' i ' : : i r r t ' - " _ _ ' "
SOH. Thc interlayer re-eion has
u'crc conductcd
All sorptionexperiments
ncgati\cl)' ch4rged sites rcsulting tionr
in thcrmostatcd
at
a
tcnrpcrature
30n"C
constant
cf
isomorphous sribstitution" rvhich ma)- bc
resscls.The backgroundelectroll''ten'as 5 rn\4
compensatedby hydi'*1e'dinferlayer cations
srtesor in the intcrlayersp?eqof ni(.rntilorillonitc
as aminopvridincscan.-l). lntclh,sor of c*tions
or urganicspeciesinto thc int!'rlaycrspEqr€*ra*l
clav rnrneralslikc montmorillonitc is knoun trr
changc thc basal spacing of thc clays -1).
to
Adsorption
organrc
rnolcculcs
of
montmorillonite can dccrcasc.5). incrcasc.4). or
l c a v c t h c b a s a ls p a c i n go f t h c c l a y ' u n c h a n g i , ' d . 2 ) .
Thus dcterminationof such changcsby XRD can
providc' qualitativc' infbrrlation rrn th!' tvpe of thr'
interaction bchtccn thc organic molcculc and
montmorillonitc.
Thc intcractionof organic moleculcsand
surlacc ol clav minerals can also be rclcntitiedbv
5q.t
suspensions the
monrmoriiloni
rt'acc
l o o n r rL
I
arL'a
of
thc
titrations u.'erc conductcd on
rillonitc suspcnsionsrr'ithout. and nith.
adtied 100 pM 9-AA. lVlontmorillonitc \\'AS
cquilibratcdin uatcr at its naturalpH tbr ovcrnight
and thcn, if ncccssary.9-AA nas addcd to gire' a
final concenffationof 100 pM 9-AA. The pH of
thc system thcn u'as raiscd to about l(i.0 brr
a d d i t i o no f 0 . 1 0 0 M K O H . a n d t h c s u s p e n s i o n s
\\'as titratcd back rvith 0. 100 M HNO, to about pH
4.0. Successiveadditions of HNO. u'ete madc
I
only afier the pH drift r.,'asiessthan 0.1 mV ntin
nhich is usuallv rcachcdin J0 rnin.
andNatumlScienccs
liC\4N-S
)
lntomaf
ir)nalflonflrcnccon \'lathematrcs
Novunttrlcr
l9-30, 2t]06.Banduns-lrtdoDcsia
Adsorption cdge cxpcrinlcnts Ineasurccl
rhe effect of pH on the adsorption 100 pM 9-AA
ori monfilorillonitc. Monnrrorillonitesuspcnsions
were pre-equilibratcd ovcrnight at their natural pH,
and rhen thc pH incrcascdto l0 rrsingKOH. Aftcr
l0 rlin an aliquot of 9-AA *as addcd giving a
total conccnhation of 100 urv-. Aticr a furthcr 30
reactionsarc givsn in Tablc l. The fit ofthc nrodcl
to thc adsorption and titration data is sho.,rn in
each ot'thc Figures.Fig. 1 gives thc titration data
for solution of 0.0 I M 9-AA an<Jfor suspcnsl()ns
I
montmorillo-nite n'ithout
containing 100 mr L
an<iu'ith 0. I mlt4 9-AA.
Adsorption edges dcscribing the effect of
inin a 7 ml. sainplc rvas rransti'rreij into a
ccnrrifirgctubc, and cappcd.Thc pH of thc stock
7 mLin steps,and turthr;.r
solut,onwasdecreased
at cach
samplcstakenatier l0 min cquilibratron
pH. All thc sarnplcs
\\'ercthcrlshakcntbr'2 d and
is
pH on tlie uptakeof 9-A-Aby nrontntoriilonrte
shou'nby the datain Fig. 2. Adsorptionof 9-AA
().I mf\'lu'a-s
uith initialconcenfl'ation
smailerthan
shrrngin lou'pH values(belou 6.5). As thr-pl{
9-AA decrcascd.
increasedtheamountof adsorbcd
.Ihc
9-AA
coltductcd at pH 4.A and 6.t).
conccntration$'ss incrcasceli&f$t1\ tionr I pM to
500 prNtbl,acidition of a stc,ii solution *[trsc pH
lrad hecn adjusted ro*pg"4.O or 6.0. A.fteJ each
atldition the i'stcm ff.-quilibratccl t'ur i h, rrith
b:- addition of K()lt or HNO-.,
the pH naintaffi
ht'l'orC a 7 nlL. iJillplc \\a\ lrdnsttrrtd IU J,
ccntrifirge tebc, and cappcd. All the sarnpleswe{e
betbre
then shaken for 2 d. and thc pfl rcmeasr.rred
thcr \\'cre centrilirgcd. artrl thc Eupcm3tant
solution analvzcd tirr 9-AA.
Adsorp;gr'isriflterms at pH '1.0 and 6.0
arc shorvn in fi-q. I A-!FH 4 0 the amortnl of
aiJsorbecl9-AA is higF*tlfrtil I pla{ear is rcachcd.
On thc other hand. at pH 6&*{e isothcnl data
shon'non-I-angmuirianbehaviorindicltrng grcatcr
amounts r-lf tirc 9-AA adsorbcd as the total 9-AA
\\as incr.'ltscd.
iorlCCntraft()n
Table i. Surfacc contplcration trodsl par:iiilsiers ti)r
a c l s o r p t i o ro f 9 - A A h 1 ' m o n t l n o r i l l o n i t c
Sitts Concentration
IlI. Resultsand Discussions
SOI{ tnnrol ttr
0"0069
l
"
Resnlts
A.
m
X- "/nint,tl
f l . Olll
l:TlR :1lssvz
lmrr capacitance(F m')
-l
In,tarcd sfcclnr indicirtt'srhe lvailahilit-v
( . l u t c r c a p n c i t a n cr Fc t t t t )
:
,rl' \H irnctional gr()Lll)s
{)n tlrc strr'lirccas sho\tx
nq"ifift.iuttt .on.r"nt.. fngt,'K. f,iisire
by specific absorption of hctrrocvclic dngs at
'. 'l'hc
l rr enrrnrbcfsrrl' aboul l lc)0 and l('-10crl
l!qq!g!t
_ pt_otsnal-ion inC igplSlln4liqq
soH.ll sOH+ tf trbsorptionof secondarl' aminc at 11,36-5cnf',
2..100
C=N in l47g - i_i02.,1cm'. and C-N sir€ql*ro*at.,.3.-*.. l?t St)tr?- SU - H
-6.64{)
'
137 1.3 cm are.afso obl'iorrs er'idcnccs of sorbed
9-AA on the sui{ace of nrontmorillonitc, but thc
adsorption docs nth"5Jrill absorprion bands,of SiO
in narc'numbcrsof 451oJ'94,an-d1022cnr-'.
tion
(l-) protonrrtion
\,
YRDDiftiuctogrunr
l'he r-axisspacing1br
I tl-
Lisi
-9.)'7|
:
t.(oHr
loglnff. for
Equilibriumconstants.
_g4a S{Cr1p!ej!_!L!tnqti9!_,
6r [X-Kl'.JL']H:
I 9.61-,[ ( X L H ) " - t L H . L+) -K] -
A. and
the abse-ricc
of 9-i\A rvas ll.ll
i n t o 1 5 . 0 7 A i n t h e p r e s e n c co 1 -0 . ( ) l N4 q-AA
(gnaphsarc not sho',vtr).
,1dsrtr1tt it n,:x pa r i n enI.stt nd mrxlei i trg
Thc sLrrfirce cornple-ration urodcl rvas
dcr,clol^*dto detcrminc rcaction mcchanismsbv
considcring specn-r)scopic data arrcl by litting
adsorptitx c'dges. adsorption isotherms and
iiiration data using a cornputcr soll\\'areGRFIT.
6). Thc nrode-l paranretcrs for thc adsorption
7) SOH * lL + 2H- z-
[(SoH)"-(LH-)]r-lr-I
59.i
t.371
i n t c m a t i o n : i lC o n f ' c r e n c eo n \ 4 a t h c m a t r c sa n d N a t u r a l S c i e n c e s( l C \ ' l N S )
N c r v e n r b clr9 - 3 0 . 2 0 0 6 . B a n d u n s - l n d o n c s i a
of thc sorbin-s
shifis and changesin the-spc-ctra
spccics.8). Theretbrc.it nas not surprisingthat
adsorbe-d
9-AA can dcsorb fiom thc surfbcc of
rapidlv.9 )
nrontmorillonite
20
10
0.0
' '-{1..
10
\
-24
c
a
E
o
p
a
-Ju
0 01 M 9-AA solulion
o
c
il*:-Aii'
\\,
t.
Totaiadsorption
60
. .b',.l ( s o H ) " - ( L H ' J" 1 " \ \ .
.\
e0
<
o
G
.
\
'r
I
:l
l(x LHJ'-lLHL)'t'
..'
00
I
pn
.:
-
|
l/
F i g . 2 . T h e e f l c c t o f p H o n t h c a d s o r p t i ( >on1 ' (o ) 0 . I
m\'l and ( ) I m\'1 9-A,{ bv niontmorillonitc. Thc
l i n c s a r e c a l c u l a t c du s i n g E ( ' ( ' \ { s u i t h p a r a m c t c r s
listed in Table l
100 m' L
monlmorillonite
w i t h o u l a n d w i t h 0 1 m N ' l9 - A A
10
pn
2A
F i g . ) . . A c i d - b a s ct i t r a t i t ) n so f s i n g l r ': u r db i n a r y
st'stcmsT
. h c s v n r h r , l sa r e c r p e r i m o n t a ld a t a : ( ) ! ) - A A
s o l u t i o no n l l ' . { A ) r n o n t m o r i l l o n i t es u s p c n s i o no n l y ' .
a n d ( \ ) n r o n t n r o r i l l o n i t or r i t h 9 - A : \ . T h c -l i n e s a r c
c a l c u l r t e t jb r ' [ ( ' ( - ' \ 1 s r r . i t hp a r a m c t c r sf r o m T l h l e l .
a-,-
18 !
o
O
o
r
12 ),a
e
ltl
a ,/'
a
B. Discussion
(j atter tt I Obscrt'u I i on
grL'atcr basal
oi'
the
spaclng
rnontnrorillonitcdrrc to the adsorptionot 0.Ot-M
9-AA slrou,s ihe importancc of cation r::(cl-iange
1). Hou'*cr.
.'=2.'.
.q
r tfupge*.ofu
sitcs (X
sitr:s) in inte'rlave
tff Bdsomtionof 9-AA. 1i':-'
nrorrtnrorillonitc
nrc\i(rils irrrcstigatir.runn adsorption ol' 2proposcdthat
anrinopvridincbv'm-ontmr:riiloniie
that adsorbcdlbasalspacingof nronimgrillonite
aminoprydi
ne incrczrscd
0rgmaticallybecausethe
nroleculesarc arranged\,"'ith
of the nng
approxirlatelv pcrpendicularto I
r
xg
- l- p
ol.,
E
6V
ol
; ,Lft.
00
0i
a2
03
04
05
[9-AA]imM,
F i g . 3 . T h e c t f c c t o f 9 - . A A e ( ) u c e , t f f a t i ( ){l)tt tl h e
( .l) p H - l
a d s o r p t i o no f 9 - . A - {b 1 -r n o n t m o r i l l < ) n i 1 ! ' a
a r r t l( ) p H 6 . 0 . T h e l t n e s a r r :t h c h c s t f l t c a l c u l a t c d
b r , I C C \ 4 s s i t h p a r a m c t e r sg i v c n i n T a b l c l .
laver.
rhc adsorption r,,'o.'*'i.-6gipry*='*t'-
primarily r)ntocxternaisites(SOH on the edgcsof
crvstals)basedon lapid adsorptronand desorptron
rate. Signiticant role of crtcrnal SOH sites tbr thc
adsorption uas also shonn bv intiarcd spcctra
titxr r.r'hich adsorbcd -NH t'uncfional groups
rdcntificd on the surtacc. but thc adsorption does
not shift the bands of adsorbcd species nreaning
that thc interaction involr,'esoutcr-sphcrc complex
formation becausc the interaction involves rveak
chenricalbond. Strong chcmica! interactionswith
srlrfaccs havc becn associatcd rr'ith significant
5q5
On the othcr harnd.thc f'act thal thc
concentrationof 0.0I \4 t)-,AA can incrcasc tltc
basalspacingof 1.84 A is oidcncc that significant
anlount of 9-AA are intcrcalatedwhen thcir initial
total concentrations
arc high.
Sur/bt'eComplexatir>nModel to Sludt,.4dvtrnl rtrr
Process
ECCNIs rvas lirstly done to titration data
of singky and biary svstcms.thc modcl tit rcry
rlell 1o cxpcrimcntal data as reprcsentcd bv tlrc
l n t em a t i o n a l C o n f c r e n c eo n \ ' l a t b e m a t i c sa n d N a t u r a l S c i c n c c s{ l ( ' \ ' l N S )
N c r v e m b e2
r 9 - 1 0 . 2 0 t ) 6 .B a n d u n c - l n d o n e s i a
lines in Fig. I whose paramctersarc listed in Tablc
l. Thc paranrctcrs are then used as fixed
paramcters tbr modcling adsorption cdges and
isothemrsdatn rvhich also produced vcry uell fit
(Figs. 2 and -t).
Thc uptakc of 0. I nrM 9-AA b1,
montmorillonitc rvas strongly pH depcndant. and
slrongcstbelorvthe pK,,of 9-AA. suggestingthat it
is the 9-AA cation that adsorbs. The model
suggr'stthe adsorptionat lou'pH fbllorl'sreaction:
SOH - lI- + ll-{- :+
[(SOHf-(LH-)r]-lrThe rcaction sussests that 9-44 c611at
maybe a co-operativc sorption mechanism.
uherebythc initiaisorptionof 9-AA increases
thc
probability of lurthcr 9-AA uptakc. Anolhcr
possibility is tht- lbrmation of aggregatcsor
clustcrsof 9-AA moleculesin solutionor at the
this systemri'c fbunclthat
surt'acc.Whcn modclin-s
the sorptiondatacouldnot be cxplainedby simply
allou'ingfbr morc'sorptionsitcsin themodcl.fhc
stoichiometrydoessupportthe hypothesisthat 9AA srrrbs in clustcrs or layu'rs aI higher
cotlccntratlon.
tbrms outer-spherccomplcx u'ith cxternal SOH ,r'-.f\.. COnClUSion
sites orr the e'dgesol nronbtlorillonitcthroegJP*
'ts+'.d
hyclrogeninteractions.
Fig. 2 sholvsthe fractionof
g-AA adsodrs montmorillonite by
9-A.A adsorbedliom total conc^ennar4tlnr$."l
nrM
fbrming ffidoutcr sphcre.complcxe.srvith pI1and I mM arc about 9i9i'. Increasing
dependently c\gafd sitcs through h_vdro-ac,n
conccntration
ol'9-AA rcqrrlrgpgiore
surtaccsitcs
hondingtoilo$in! a ruact!x|:
r o a d s o r ht .h a t\ \ i l l r c s u l irr rd b t i c a s i ntch c f r a c t i o n
SOfl , ll +:H :dlflSr)l,lI,_tLH ). lio1'9-AAthat is ableto adlprb. ln tact.,the-.Jlaction and *.ith pernlancntncgarircfu"g4|argcd
sii..sboth
of 9-AA docsnot de&#; indicatingforiiaiionof
ori facesan.lint.rluu",regrons
\,racarr()1
cxchancc
9-AA clustersj&solution betbrc interactingthe
reilcti.oli:
surlhce
. lsothcilnsdataat pH 4.0 alsosupportthe
l,]l.L)-l- - KIX -K-.Io+3L + 2H- =-- |XLH),,-(
assumptionu,ith very high adsorptir'ccrpacit5;o{
surt'accl;itcs.Furthere'videncctbr this nrechsnisril
V. RefefenCeS
comesfLom vcrv rapid kinc'ticsorpfitll rsported
prciiously.9)
l.
tr!.J.
J. Ikhsart,
J.D.\\clls. B.B.Johnsr.rtt,
Thespeciation
drau,nin Fig.2 showsthat
Angcve,ColloidsSurf.A. 252.-il {20051
cxisrpredgminantly'
t(SOHf -i'LH-).t-lt-conrplc-x
l.
I'1.F. Brigatti.C. Lugli. S. ivlontorsi,L.
at lou. pH antl rcsponsiblc lbr mrlrit tonl
P o p p iC
' ' l a 1C
' sl a l ' M i n c r4. 1. 6 6 1 ( 1 9 9 9 ) .
a d s o r p t r oonf 9 - A A .
I
J. [khsan.N'l.J.Angove. J.D. Wc-lls.ts.ts
S{o.Jcl also assumesan ion exchanee
Johnson,J. ('olloid [ntcrfaceSci.J8'1,38.1
intcractionw'ith negativcsifcson rhc'clay at high
(:{X}5)'
pH r,alucs:
A
.H. Gem"-aA
4
y ,. S .E l - S h c r b i nA
y '. t s .Z a k i .
1
K
*
IX -K-lo + 3L + 2H-r[XLH]"-(LH.L)lJ. ColloidIntert'ace
Sci.24-5.116{1001)
ln the aboyereactionu,cha'c.rynnenthe
i.
E. I\4ordlo.
J.L.Pcruz-Rodrig"uuz.
C.
cxchangcdion us K- bcuauscrhc,re-layrvls
Clar Mincr.26,2691la9lt.
potassiumsaruratcd.Cation crclr.,,lg.*Stl* 0"F-".' t"- Mriqtrdda.
6.
Lud*'ig, C., GktrIT - A Contputer Progntnt
rnontmorillonitt:existin silica shcetsprcscnton
outer f'acesof thcr".cla.v
and in intcrlayerrcgions.
.|itr SolvingSpeeiationPrghlems. Evu\uuIitttt
,,I Etl tti Ii br ium Con.,trp*is.(t t, tr'( tI! t'(tt i | |tt (tt| (|
XRD dataindicatei*tq-actionof 9-AA also in thc
O tlaer Physicdl Ptprit etc rs. Sn'itzerland.
intc'rlayer rcgi0ns oi
signilir:ant incrcasr' in the
1.
S. A(y115sif.-.{ki
iis.J.F.D.Darics.J. ol'
. 119941
S t r u c t J, R : - - 1 x - J1 Q
species becomesmorc impoftant at hisher 9-AA
conccnn?tions.
-l
he most interesting aspect of our
inr cstigation u,as the incrcased uptakc of 9-AA at
high pH as thc total concc'ntrationincreased.This
is cicarly denronsfratedb,vthe uprvard cun.aturc of
thc 9-AA adsorptionisothermsat pH 6.0 tFig. -l;.
Thcre is a number of possibleexplanatronstbr this
bcha'''ior. Firstly, thc number of acccssible
:jorption sites ma)' incrcase as the. q-AA
concenffation increases. Alternativelv. there
5q6
B. B. Johnson.S. Sjoebcr_e.
P. Persson.
of MelliticAcid To
SurfaccComple'xation
Coethite:An AttenuatcdTotalReflection
FourierTransformInfiaredStudy.Langntrir,
20. 823(2004).
J. lkhsan.E.Widjajajnti
LFX, sunarto.
M. P
Artianty.PenlakuSorpsi9-Aminoakidin
olehMontnrorillonit.
Prosiding
Scnrinar
N a s i o n aP
l :e n e l i t i a P
n .e n d i d i k adna. n
Pcnerapan
MIPA. Kimia FIVIIPA.
UNY
Yogyakana,I Agustus2006.