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Authors: Mathew, John
Issue Date: 1977
Abstract: fit ioa*excnaage process, an exchange of tone of like eigne occurs betweea a solution and a pervious inaoluble matrix in contact wth the eelution. M exchangers can be organic or inorganic materials, la either natural or synthetic form. The essential reonirementa of an ion exchanger are that It be of high molecular weight, insoluble la water, sad capable of exchanging mobile tons with aa aojueoua phaae. It can therefore be a liquid, an example of which is ths long-chain amines employed for separation as well aa purification purposes. Most commonly aaed ion exchangers are, generally, molecular polyelectrolytes having cross-linked structare carrying fixed tonic groups. The laminar or poroue structure permits the of the labile counter-ions bound to the tonic groups. In many respects ion-exchange resembles adsorption, the cardinal difference Is that while Ion-exchange takes place stofchtometrically, in adsorption the adsorbent takee up the datsoived species without releasing others toto the solution. History and application of Ion exchangers The earliest systematic studies1"4 onion-exchange deals with the base exchange properties of materials present in soil, at 1803, Harma and Rumplers made the first synthetic aluminoeillcate exchanger and la 1808, Oans9, for the first time produced and employed synthetic sodium permuttte for softening hard water. Polto and BeU7 uaed synthetic seollte for preconcontratlon sad separation of ammonia from biological wastes. Column technique for quantitative analysis waa first employed by Whttshora8 who was resumetile for ssaarattas snitnss from btolosical ssianles. BaajMaat>. to 1833, true Industrial era of ion*enchange waa ushered at, with the synthesis of phenol formaldehyde cation and anion exchange rosins by .8 have bean synthesized. Currentty, the commercially available ssrehansa restes are stronelv acidic or weaklv acidic ftftfru • strongly saaas or weamy ossx; snton exensngem, counng rwi mm atowittewsrienssst lsaan ls owna -wesxe*cMhM^aMsnsgsn^e* e^whiniwM^pwnwn^^a^wtif^tgjg^*r^s»gnj^twiyyy hw»e^i|gi»hrt»ewn»»e,d« a^•lwta" r the development of synthetic resto exchangers and the Introduction of V9eve#eeVanagK^v aaaB^l^P* aaa«a^a kr^a^B^wj w w^*^s)fi*a^"a %? usas^* \x^* a, v ^aaaa a^^^^n ia e»^^^n^^a^a to ulcer aad edema therapy, aa artificial kidneys, aa bacterial adsorbont and aa catalysts as wall aa the conventional uses such aa analysis of orsi eiy* alloys, pharmaceuticals ajnd fission products testify to Hie widespread applications, la fact, the growth of loa ns unit operation baa been ] eaualbrtum between tons A and B of charge a aad b respectively may be represented by the equation a b a Bb ♦ Ib IX -=^ 1a I ff ♦Ibi A 3 the bars indicating the exchanger phase. The above equation obeys tow of mass action aad the thermodynamic equuibrfcim constant can be derived. The two main characteristics of a resin ore capacity, l.e., the amount of tone that are exchangeable per unit quantity of exchanger, and selectivity, Le., Hie restriction that only tons of a certain type are exchanged. Apart from this, the two qnanttttos which are more important from the point of view of separation are distribution coefficient Kd, and selectivity coefficient, K-^A. Both can be e?tpnr1rft*T>ifr*lHy determined. The dtetrfbutton coefficient to a direct measure of the extent to whtoh an ton la removed from solution aad la defined aa His number of mlUleontvalents of en ion adsorbed per gram of the exchanger divided by the number of raHUequlvalenta of that Ion per ml remaining to the solution at equftfbrtom. Ot the baste of selectivity coefficient, the relative offmates of tons for aa Ion exchanger can be quantitatively evaluated, ft to equal to the ratio af coaceatretione of Hie two ions la the solid phase divided by that of their concentrations to solution at equilibrium. The thermodynamic equiltorturn constant to given by the following equation s a |h | _ | a | |b [b] U] b a -.]'•'[xjM V*1^ *v la sn^^Bh dtoaaa aa^aa>4aa>8aaaa ssjeeaiaY£saie9BaB*sn *Pftftaa evaluation of K becomes difficult aa the values of activity coeffSclents in the exchanger phase are difficult to determine. Owing to the great practical utility of selectivity, many approaches, both empirical10 aad mechantotic11*17, have been made to the understanding of ton-exchange selectivity. The various factors which contribute to ton-exchange selectivity are non-unlformay of exchange aaes, tonic hydration, ion-ion interaction and swelling of Hie exchanger. Theory of lon-eachangc The various applanations that have been proposed for the mechanism of ion-exchange boft down to three theories: a) the doable* layer theory, b) the crystal lattice exchange theory and c) Hat 4 18 •apva oooJPlasstoPw^gpajw w» aae^a'aan^ gnna •^e,» wmsis ^n# •^^••••••''^^w^* ^ssw^# 19 11 later modified by Ouoy*" aad Stera , as an explanation of the wJiflP0fa»5KaaWRa*W gpnwPg^aaHMPWP lest !SlP<MaPWilPj| g^alaw Ir^faaaa wal^8filf*i IW Wa»g^BBa«at the vartoua phenomena assoototed with ton-exchange. According to the theory, aa toner fixed layer to surrouaded by a diffuse aad mobile outer layer of charges which owaa their existence to the adsorbed toast they may be different from tons that are already present In the toner portion of the colloidal partidee. The Ions present to the %Woaaa<sv aoaBUMnSB^P de^njF^»w> ^aenw^^saxa aana^^ nan** ^Ptosj^amaa^ne* a*^ej^a^* p^punnw ^w«w .mmnr sharp boundary between them. And so depending on the concentration and pH of the external solution, the concentratton of the tons a constituting the diffuse layer vary continuously. Aadtfthe equilibrium to upset by the addition of foreign tons, acme of the new tone wttl enter the diffuse outer layer replacing some tone prevloasly held to this layer. The exchange to stoichiometric since the law of electroneutrsliiy must be m*tats feted. However, cryatal lattice —»!•*••• whtoh aaanmes that a fixed number of exchange sites must waysaaeaegnw ws*an»se sp^sspnsee^^nr i^mp^"» ^» *^^^w^ ^^^mhiib ,m,p •* ^^ " "• m'*»—•**^p^r • ^ be sattofted regardless of change to pH or concentration, may also The Donnan theory deals with unequal distribution of tons exchange equilibria, the Interfaae between solid aad liquid phases may be considered as a membrane. The non*diffuslble ton to the collokinl micelle to whtoh Is attached Hat exchangeable ion. The I1«M theory to TMfrfr useful la ^vptelntng exchange to ententes, phosphates aad ion-exchange reetoe. AH these theories are essentially similar because of Hie fact that the law of electrcneutrslity governs the exchange of lone. They differ only In Hie position and origin of exchange often. la the past, the study of inorganic ton exchangers has bean overshadowed by the much greater interest to organic ion-exchange restas. It to interesting to note that the first aalaatrlal aaaftoatlon of materials6 (synthetic permittee) to the early years of this century. The subsequent development of organic exchangers possessing grantor stability and capable of controlled synthesis to give products wfth ranwxtocibte nroaerttea, has largely dtoataced their toorganto counterpart m moderntechnology. But the application of organic resins to bridled by their breakdown to aqueous systems at high temperatures and in presence of ionising radiations or highly extolsto* modto ± la recent yeara, there has been a resurgence of interest 8a toorganto exchangers whtoh haskUTfoly stemmed due to the followteg reaaoaat s> a **w8P** ^*"Sa^8aa8B3a^ft^8Ka> ww waa 3MWa8wp ^pnaaatoaaFg«. ^aaa w^pm*»»j^nw* *fv **^"* •^•c airconlum phoaphate, are generally, more stable Ham the early atomtoostttoate exohangera, 38*38 3. They are more resistant to heat aad radiations Ham their organic counterparts, bo that several new gatanjial aa-aioaiiom to to^ 8. These matertole are, ganeraUy, eaay to sjsthaalaei owing to Htto, exohangera with desired selectivity can be prepared so that difficult aeaarationa can be conveniently carried oat oa these exchangers. 4, Recently, toorganto exchanger, have found new aafalcattom to water daaslteation arooeaaea20, in fuel cells39. 4 ##ta* a^^nansnaaaBiaaasaV ftfjgv %A aaaaWaPW* w of hydrogen tone, and toelectrodyaltols. 3. Moreover, Hie atudtos on inorganic ton exchangers throw light on the sorption of tone by jwclaftatea, the eleetronhorette behavtour of suspensions. Hie diffusion of toaa to crystals, tootopte exchange to heterogeneoua eyeteme, and many other aspects of 88>aafteaa m a^anpw arnan^^aaa^wa* j a The first reaortsca eyathette toorganto exchaagara for Hm ,82 treatment of reprocesstog solution were published byRuaael at el and by Beaton et al33 to 1843j these reports were not declassified until 1887. During Hie last few years attention has bean drawn, la^ipallybyKraaaetal84*31, Ampjott •nrfeoworkereaMM*, Ahrtond and esaoctetee38"40* m% A&ertl and his group41*44, to the feaafciiittes of using theae materials for high-level waste treatment, recovery of fission products, aad high temperature jU»-exchange. During His past few years, a large number of synthetic ktorganlc exchangers, bothamorftoonn aad cryetaillae, havobaan ayntheatoed, aad Htelr toa*exchange pronertlea investigated. M Idea of H» raald^ growiag la the far* that whan Hte book *1bn »»ltoager,by F. HeHfertohwaa published In 1882, only two pages ware devoted to synthetic toorganto exchangers, butteat aftertwoyaara a monograph on toorgaafc exehengere by C.B. Amphtott waa published. 8 Since then, numerous materials have been axfiorod tor Htoto exchaaga potential. The iwogress to this area has also been revtowedtoa number of articles. A priori, it to difficult to classify Hie toorganto exchangers aynthentoed, aa avartety of exchangers have been ironared. 49 (2 44 Bat according to Vesely and Pekarek , aad Alberti and C<xtet_*ntiao , synthetic toorganto ion exchangers can bo classified aa follows! 1. feaotohle acid salte of polyvalent metals, e.g., airccnium phosphate, cerlo araenate etc. 8. Hydroua oxides, e.g., hydratad oxklss of airccnium, tin, titanium etc. 3we. eSPtaeialwtasa oam*f haieaateeerwo/jgoFowlny^«a*c*^lmdmai£. e™r.wgsa».a.* ..- —a a. S j ^la m •.^JaShftil mm, a' SSM^mbp w^wwg^^»^^wgf !«»tmis'"a• iiBa *m^"**i setose. ews. 4* ltoohtble ferroeyenldee, e.g., ferrocymldee «$ aircontom, titanium, copper etc. 8, Synthetic aiumteoaHlcates, e.g., aeoHtea wfth general formula Ha^O. M^ a SIOj, where a• 1*13, 1.0,, clays aad lamellar zeolites. 8. MteceUaneoua toorganlc exchangers, e.g., mercarblde Amongst all these, the acidic salts of multivalent elenaents form ana of Hie most extensively studied series of toorganto ton exohangera. The metals studied are zirconium (TO, tin (TV), laaulini ttV), thorium (IV), certom OH ahtmtotom (XH), chromtomCH), 9 iron <m% vamtadtem (*r% urantoin <TO1 etc. Those mterocrystaHtoe or gel-like materials act mostly as caile* exchangers, and the cation exchange properties have been aecribed to the readily bvdmaen tona associated wfth Hie intofite ffrouas present to me exchangers. Some of these exchanger- exhibit 51 electron exchange properties too . There has been a special emphasis on the ealte of quadrivalent metals, which to probabte doe to their better chemical stabHfty aa compared to the salts of bivalent or trivalent metals. Zirconium phoaphete was the first teaohibte |aHyl>w uaed as an Ion exchanger, and ft te^aont krtenstvely atadlad compound. Alougwtth a few others, ft la commerctoUy avaHable. Various samples of this exchanger with variable ZrOg : P2Os rattoa, aad poaaeaatog different exchange properties have been reported to Hie literature33*4$*52*53, Amphtett40 suggested that, toslrcontom phosphate, ton exchangetakes place by the exchange oi hydrogen ton from P OH groups, whtoh are bonded to Hie water molecules, via., P*OK *— OHj ♦ M*^P—O" -mSbO* it hydroue oxides alao3,|,84, aaimiter mechantom has bean proposed. 1st 4-1 mZr— OH) •, aar • {»~Zr*~0) ♦ all (*^r**OL m *nti iO The uptake of cations wlU not only depend on Hie tontoaHon constant for the hydroxyl group to atep (a &»* **«* ©a «»•****** aft^fttoa of ,~Zr~0 ferH*and Wf to step (3 J, that Is, oa the readisess with whtoh In** aaaaetetee wfth Hte oxygon In Hie matrix. la Hie oaae of inorganic Ion exchangere tt is not unusual to find eometimes some other mechanism also operattog coupled wfth I. For example, precipitation mechanism also plays aparttoHtoa|«ahaofcatlona. veeely at at33*W have studied the uptake of di and tervalent tone onaranyl lrydrogen phosphate and explained Hte sensation to terma of Hie formatton of simpte metal phosphate. A aImilar mechanism has also been reported for se of bivalent metals, e.g., calcium phosphate"', 13 59 hydrogen phosphate , and copper phosphate . The adaorpttoa of Pe3* on amorphooa airccnium phosphate has been exptetoed00 on Hte baste of a process tovolvtog its aHroductton Into Hte matrto of the sorbent. it aa snalogous manner, Hte retoiteete atrong uptake ^of w^mm^ mmmmmmmmmmmmmm aaor food to a chemical Interaction between these anions and Hte M At times, Hte sorption may owe its origin to surface adsorption or some electrostatic forces. Jtorry and Fuerstenau0 carried eat many interesting studies on Hie surface properties of airocntom phosphate, ft baa been proved Hart K* and U* are attracted electrostatically to the surface of the solid only whan the Is negatively charged; on Hie other hand, ions whtoh farm il toeohtble phcaphatea, such as Ag+ are chemtoorbed even whan me solid Is posttlvely charged, tf ftofttee to aay, that la Inorganic Ion exohangera, the uptake of tons Is mere complicated than simple ton exchange and structural changes to Hie heat material also hare to bo taken Into eonsiteration. Recently, some of Hie toorganto ton exchangers possesstog fixed composition and weU-deftoed crystalline atructure have been prepared. Alberti, who has presented Immense work to this field, 44 dtvidea these exohangera toto the following subgroups i a) exchangera having a layered atructure b) exchangera having a fibrous structure c) exchangers having an aa yet unknown structure. ft baa been observed mat crystaUtoiiy ensures atabHity of Hie product and specificity. For example, xircoiitom aheeahete (obtained for the firet time to fuUy crystalline form by Atoertl et al.) and tto phosphate becomes more stable towards hydrolysis , whitethorsim i03 shows specificity towards lithium ions. Some of the other exchangers that have been obtained to crystalltoe form are phcaphates of titanium, thorium and cerium0 , and arsenates of sircontom, certom and titanium70"72. Alberti and coworkcre synthestoed cerium (Rf) phosphate69 and Htorlum latoaahate3*. These are the only two insoluble acid salts of tetravetent metals havtog ffbroaa structure. Crpstallteation brings about purity of Hte product, aad as a result, it facilitate- a better understandtog of Hte exchange process. Furthermore, tt provides a solid basis for Hte toteraretattoa of thermodynamic measurements. 12 A&ertason73 haa ahown that atrooatom phosphate of different crystaUtofty posseas very different properties, ft haa also boon ahown40* ••n thatfroma practical aotot of vtew. »trcontom phoaphate goto are mora suitable than crystalline ZrP. Aad the fact that many inorganic exchangers areemorpheuadoeenottaeaywayb^ The numerous examples of Interesting separations achieved on materials, cited la the monograph by Am|«ttett40 and tea review by Veeely and Pebarok49»* toatfty to Hte iqenlteaJton of theae Another important aspect whtoh merits conaldemtion as regards the separation potenttolfttes of toorganto exchangers to the use of paper iinaresnated wlto thc^e inaterXUfl. The separation on theae papers depends not only on partftlon, but also on selectivity as ahown by the exchangera towards various tons. Albert! etal. were the first to report the aeparatton of allaUl metal tons on molybdoohoaphate paper and Htey, to their numeroaa have shown the teteaa^gea of paper Imare^ wfth inorganJc iaflhjejgsrs over untreated papers and resta impregnated papers. The mate advantege of chromatography on theae papers over jawttttoa chromatography to that the organic mixtures usually employed aa solvents can be replaced by aqueous ahteata thereby reducing Hie separation time. These papers have aleo been explored for Hie spot teste of metal tone , the separation 73 of ahort-Uved radtoetomente •**&*««* adaorptton 13 equttfbrto77 and also for electroahoretlc studies78. Further, soma of Hte biochemical separations achieved include aeparatton of amino acid, on xlrcontom phosphate73 and hydrous aircontom oxide paper30, and afiealoMs on «t**ontom ifcosphate31 had titanium arsenate paper32. Various tea exchangera that have bean aaad for impregnation aad tea selective separations achieved are enlisted to the reviewe by Alberti33 aad also by Qureshl . The pcteattoltttos of lea exchange separatloa can be fully exploited only if consideration to given to both equilibrium aad kinetic aspects. These are largely independent and they differ with different ton exchangera eaenthongh Hie exchange groups may be the same. Bven Hte same exchanger wfth different wteer content mav differ mHte occhanse rates •6. In coatrMltlaaitlon to the aaiaww UiAfew* *aa eaa*te awaaeaaimaafjjap a w^^aa a em» ^t^mmmm m m«h*^^^^ ww ^^»^ extensive and fundamental work on equilibria and thermodynamics. relatively little e nafcleration haa been given to Hie ktaettoa of ton* exchange. Neverflteless, experimental and theoretical work la recent yaara has led to a clear-cut understanding of Hie general aspects of Hte fctnetfc behaviour. Holftertoh33 has covered Hte mtchanlstte-thoorellcel approach aa regard! Hte ion-exchange ktoettos. Dlffualon of ions, wfth an electric field aa the of etoctroneutralfty ooaaervaHoa te the baste of tee current quantitative theories of kinetics of ion-exchange. The rato-controlltog as step was first shewn by Boyd et al . to be diffusion either in the particle itself or to an adherent etagnent liquid layer called Hie fHmj la an aa^rmedtete range of conditioas bote M niochaalsms may affect the rate. As such, little is known of the ktoetlcs of Ion exchange on toorganto exchangers. Particle diffusion has been found to be the rate-controlling etoa for Hte uptake of ions on ton exchangers each 37*89 aa ZrP, hydrous oxides of thorium, titanium and zirconium dteee8hi0W la conatoerably influenced by pH. Recently, on taatetam arsenate01. ft baa boon ahown Htet the rate-determtotog atop on hydrous alum the slow step whtoh datermtoss the reAe of exchange of acme ions hasbemobservecltobedlftoeiontoroughpsrtlcle. MostofHteae •asiillaai liahaito Kandtote itlraailtsftll f^jiarteaastaH £H*% aaax*sfcax#naa3l3l isiai flat Mate 4|l^ff|fll Oe4a03Wa» aawBwftl ar^Mpftev IftftaTwW^a^ftJft iVWftalial IPft^ ^BWwWftsftJ^Ptenswaap a^ aian ****** coefficients, since it can daaorlbo Hte ntobilfty of Hto tone to tea exchanger. Added to this, it might give a clue to the "degree of oisjaneaa1'82 ofthe ehannela through whtoh diffusion takes |snee. Moreover, Htere exist Hie possfbHlttos of separation baaed on differences of rates of exchanges Hate, however, have act been fully Of Hte different groups of toorganto exchangers, phosphates aad araeaates of auadrivalent motels have received greater Interest, to terms of both separation potential and structural study. A survey of literature revealed Htet vary little attention haa bean paid to Hte of quadrivalent i^trivelent me Recently, GUI and i33* Hreported Hto ion-exchange propertlea of cerium fJT) and tltantom (IV*) antimonates. They found that the sntimonatce from antimonle acid wore batter la exchange capacity aad inechantoal strength than Htose prepared from pyroentimonate or antimony Id f. Therefore, It becomes neceasary to aynthestoe antimonates of other ojaadrivalottt elements also under identical conditions, so that a comparison canbemade. The ion exchangers chosen for Hie present Investigation are the following: nag W'Sto ^e^iapeaaaasa ^^w y «^www#iww"»~ ^stag aeaa ^a * y *aapeim^a^^e" fHi) chromtom Oil) antimonate **awteaT^ft^aw^e«t'a ftsj^tow^a ^e^a^s ^w n^^^^ea aaa w^a *ip^w^sas»m^^ww"T " w^^^^^* *^* a*^^1 utility of airoontom (IV) and chromtom OH) antimonates aa ton sjCPBjgp a 41 as* wftw g ftsaawHa^a^^wfflHPftWF wftessjp la^BJh^tee^^tea' waa aaspw aaa#jp^a aa^Prw eto*aF synthesis from antimonlc acid would still Improve Hie exchange characteristics, ft has already been reported93 to poasess high Hiermal and chemical stability. Chromtarn (HI) antimonate waa atedied for its ton-exchange behaviour particularly to compare its exchange charaotertottos wfth Htose of satlmcnates of quadrivalent elements. Besides stadytog tea analytical applications of these exchangers, whtoh has been tee author»e mate object, a brief incuraion has also been made j*mn>4^ A^k^h tfadk^^K^jhdto*w^m% snttne^^Mftm j%0 djAnaa saa3ft8*d^W9'8dB:3 •Jasftnp •farto 8Bte87^an8a8ft)a>^na> ^nsojp^Wsw.w *aa aaa>w aaa^aw^aa a^se>a While syntheatotag Hwee ton exchangers, special emphasis has been told to obtain samplaa wfth high exchange capacity, enough mechanical aad chemical stability and wfth reproducible behaviour. To this end, different samples have been prepared under varytog conditions of pwxapttetton. The composition and icn-exchange capacity ofteeaampleshavebeeadteermtoed. Meet of Hte detailed studies 6 have been confined to ate selects the highest exchange capacity, whtoh invariably haa the best mechanical strength too. The chemical atabRtty of these exchangera makes It clear that they offer a wide workteg range of acid-alkali concentration. Further, their thermal resistance and regeneration power also proved to be fairb/good. Cn the basis of composition, thermal studies, l,r. spectra, aad ion-exchange capacity, tentative empirical formulae have been easignedto theae mteertola. X-ray studies have revealed that Hte exchangers are not completely amorphous to natures attempts to make teem cryateiltoe were not successful* Thevartoticnofthedlstrlbutkme concentration has also bean examined and ft shows that exchange of alkali metal lone obeys Hie mass law, while other Ions WMiheagn atotohlometrtoaHy only to a certain range of acid concentration. To show the practical utility of theae exchange™, Kd values at pH 2*3 of several metal ions have been determined and on Hte basis of this, several separations of analytical and radiochemical interest achieved. Aside this, Hte measuremeat of Kdvaiaee ovtooed Hte atrcng afffatty of the antimcnate es«ttong*rs towards metal tons, auehaa Ag<& TlfH, Pb0R, HgOB, Cafln, SrftH, BiCHH, Tb(HD aad Co 0V). To explore Hte analytical applications of the ion exelamgcre farther, chromatcgraphlc behaviour of 38 metel lens on paper wfth Hte antimonates of Zrffl) and Sn &V) has bean ii i Ma MmmhSIm w*« av*U*hto at the BOSSlhlS 000 Of these Impregnated papers to aqueous systems, especially toorganto acids, for the separation of metal tons. Further, chromatographic separation of metal ions on zirconium antimonate paper waa not reported before. Baaad oa the Rf vetoes data, obtelned to aqueous systems and butenol t HCl (80128% 20-25 binary, ternary, quaternary and/or centenary separations could be achieved} allthe separations with aqueous entente have bona acoompltohed wtthte 18 minutes. Worthy of special mention Is Hie rapid separation of microgram quantiHes of alkali metal tons on alrcontom antimonate paper. at order to understandthe theoretical aspects of oeiau^ttons, a radiochemical study of Hte cationlc dlffualon In Hte exchangera has also been carried out. The slow stop that ditortoteee the rate of exchange haa been found to be particle diffusion. The rate of exchange of Rb+ and Cs* on alrcontom (W) and tto (W) aatlmoaatea has been studied over Hte temperature range of 20*3O°C. Values have bean calculated for Hie dlffualon eoefftotottta, energy of activation and entropy of activation. Furthermore, Hie resafta obtelned have been compared with the extottog data on organic rectos and other morgank excnangeiw. ft haa been known Htet in favourable contrast to organic resets, geaerefly, synthetic toorganic too exchangers possess good 26, 37, 88-101 ^ radiation stability. However, very few reporte "* m «*** to literatere regerdteg the testing of toorganto exchangers agateat i8 rays and charged partteles, ftstoha et al1?1 to arecent publication have ahown that no g^eralioaiion canbe made as regards tea aaad i wsliitemm af toorganto exchaagors agatost ioaliteg radtettons. to Hie light of the above facts, to explore the utility of Hie antimonate eaclatogera eyatfatotend ay H^ high levels of radioactivity, it becomes necessary to study Hte effect of gamma radiations on thoao inatortete. Towarde this and, Hte exchangers were Irradiated to a gammadose of ^10 rods la* nuclear reactor after abut down. The effect of gamma radtettons on Hte exchange capacity, Kd values of some motel toes, and chemical stability was exaintoed. Further, studies onHis ktoettos of exchange on Hto irradtoted samples were also carried out to tavestigate the extent of damage Imparted to these materials. For the sake of comprehonstoenene, the detailed study on the three anttamaaao tea axohaag^ five chapters: 1. Synthesis and preliminary ton*exeheag< 3, Dtetributioncoefftotontmeasuremstesaito 8* catooaiatograiivofiaote^ 4, Studies on Hie ktoettos of ion-exchange 8, Studies on Hie effect of gamma radtettons on the exchange Every offort haa been made to mtotmise repetition; nevertheless, at times, ft haa not been feasible to avoid ft.
Other Identifiers: Ph.D
Appears in Collections:DOCTORAL THESES (chemistry)

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