TRAO ĐỔI ION

7/21/2019 TRAO I ION

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TRNG I HC TN C THNGKHOA MI TRNG & BO H LAO NG

Qu Trnh Cng Ngh Mi Trng

CHUYN

Qu Trnh Trao i Ion

GVHD: TS. Phm Anh c

Nhm sinh vin thc hin:

Nguyn Hunh Tho UynTrn Quc VitHng Vn T

910022629120226691202259

Tp H Ch Minh, ngy 12 thng 11 nm 2014


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MC LC

CHNG 1: GII THIU V PHNG PHP TRAO I ION ............. 31.1 nh ngha .............................................................................................. 3

1.2. C S Phng Php Trao i ion ........................................................ 41.3.Vt liu trao i ion ............................................................................... 5

1.3.1 Vt liu trao i ion t nhin ........................................................ 81.3.1.1.Sn phm hu c t nhin ..................................................... 81.3.1.2 Sn phm v c t nhin........................................................ 8

1.3.2 Bin i t nhin trao i ion ........................................................ 91.3.3 Vt liu trao i ion nhn to ........................................................ 9

1.3.3.1. Ion trao i hu c nhn to ................................................ 91.3.3.2 Vt liu trao i ion v c nhn to .................................... 14

1.4. Nha trao i ion .............................................................................. 181.4.1 V cu to ..................................................................................... 191.4.2 Tnh cht vt l ............................................................................ 201.4.3 Tnh cht ho hc ......................................................................... 221.4.4 Phn loi ...................................................................................... 24

1.4.4.1 Trao i cation ..................................................................... 251.4.4.2 Trao i anion ...................................................................... 27

1.4.5. iu kin s dng ca nha trao i ion ................................... 30CHNG 2: C CH TRAO I ION ...................................................... 30

2.1 .Th t trao i mt s cation thng thng ..................................... 322.2 C ch ................................................................................................... 322.3 Cn bng trao i ion .......................................................................... 362.4 Thit k ct trao i ion ...................................................................... 37

CHNG 3: TI SINH ................................................................................. 41CHNG 4: NG DNG ............................................................................. 41

4.1 Lm mm nc cng ........................................................................... 454.2 Kh khong ......................................................................................... 494.3 ng dng khc ..................................................................................... 53

CHNG 5: KT LUN .............................................................................. 56

TI LIU THAM KHO .............................................................................. 57


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CHNG 1: GII THIU V PHNG PHP TRAO I ION

1.1 nh nghaTrao i ion l mt phn ng ha hc thun nghch trong c ion (mt

nguyn t hay phn t b mt hoc c mt electron v do c c mt

in tch) t dung dch c trao i cho mt ion tch in tng t nh gn linvi mt ht rn bt ng. Nhng ht trao i ion vng chc hoc l t nhin zeolitv c hoc hu c c sn xut ra nha tng hp. Cc loi nha tng hp hu cl loi ch yu c s dng ngy hm nay v c tnh ca chng c th c thitk cho cc ng dng c thtrong khng c s thay i vnh vin trong cu trcca cht rn.Vic trao i phi c mt cu trc mng m, hoc hu c hoc v c,c th mang theo cc ion v cho php cc ion i qua n.

Trao i ion c s dng trong iu tr v cng cung cp mt phngphp tch trong nhiu qu trnh. N c ch c bit trong tng hp ha hc, nghincu y hc, ch bin thc phm, khai khong, nng nghip v nhiu lnh vc khc.

Trao i ion l mt cht khng tan trong nc c th trao i mt s ionca n i vi cc ion tch in tng t cha trong mt mi trng m n tipxc; nh ngha ny l tt c cc bao qut. cp n mt "cht" hn l mt hpcht bao gm nhiu trao i, mt s trong s l sn phm t nhin m khng cmt thnh phn c xc nh r. Thut ng "trung bnh" tha nhn rng trao iion c th xy ra c hai dung dch dung dch nc v nonaqueous, trong muinng chy, hoc thm ch tip xc vi hi. nh ngha ny khng gii hn cccht rn, v mt s dung mi hu c l khng th trn ln vi nc c th tch ccion t dung dch nc bng mt c ch trao i ion .

nh ngha cng ch ra mt ci g v qu trnh trao i ion. V c bn n baogm s tip xc gia cc trao i v mi trng, trong vic trao i din ra.y thng l mt trao i ion rn v mt dung dch nc. Thc t l cc ionc trao i c ngha l trao i phi c ion ha, nhng ch mt trong s ccion trong trao i l ha tan. ion c th trao i, trong khi ngi kia, l khngha tan, c th khng lm nh vy.

Cc tin ch ca trao i ion thuc v kh nng s dng v ti s dng ccvt liu trao i ion. V d, trong lm mm nc:

2RNa++ Ca2+ R2Ca2++ 2na+

Trao i ion R dng ion natri c th trao i canxi v do , loi bcanxi t nc cng v thay th n bng mt s lng tng ng vi natri. Sau, nha canxi c th c iu chnh bng dung dch natri clorua, phc hi n trli mu natri, do , n sn sng cho mt chu k. Cc phn ng ti sinh c tho ngc; trao i ion l khng thay i vnh vin. Hng triu lt nc c th


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c lm mm trong mt mt khi nha trong sut mt thi gian hot ng trongnhiu nm.

Trong x l nc cp, phng php trao i ion thng c s dng kh cc mui, kh cng, kh khong, kh nitrat, kh mu, kh kim loi v cc

ion kim loi nng v cc ion kim loi khc c trong nc.

Trong x l nc thi, phng php trao i ion c s dng loi rakhi nc cc kim loi (km, ng, crom, nikel, ch, thu ngn, cadimi, vanadi,mangan,), cc hp cht ca asen, photpho, xianua v cc cht phng x. Phng

php ny cho php thu hi cc cht c gi tr vi lm sch nc cao.

Trao i ion xy ra trong mt lot cc cht v n c s dng trn cs cng nghip t khong nm 1910 vi vic gii thiu s dng lm mm nc tnhin v sau tng hp zeolit. Than g hot tnh, c pht trin x l nc

cng nghip, l nguyn liu trao i ion u tin n nh mc pH thp. S rai ca nha trao i ion hu c tng hp vo nm 1935 l kt qu ca s tnghp cc sn phm ngng t phenolic c cha mt trong hai nhm sulfonic hocamin c th c s dng cho vic trao i o ngc ca cc cation hoc anion.

u im:- Rt trit v x l c chn la i tng- Nha ion c thi gian s dng lu di, ti sinh c nhiu ln vi chi ph thp,nng lng tiu tn nh.- Phng php x l nc thn thin vi mi trng v n ch hp thu cc cht snc trong nc.

Hn ch:

- Nu trong nc tn ti cc hp cht hu c hay ion Fe3+, chng s bm dnh vocc ht nha ion, lm gim kh nng trao i ion ca nha.- Chi ph u t v vn hnh kh cao nn t c s dng cho cc cng trnh lnv thng s dng cho cc trng hp i hi x l cao

So snh vi hp th:Trao i ion ging nh hp th bi v c hai u l hin tng b mt, v trong

c hai trng hp rn chim mt cht ha tan trong dung dch. S khc bit ctrng gia hai hin tng ny l hin tng cn bng ha hc ca trao i ion.Mi ion loi b khi cc ion trong dung dch c thay th bi mt s lng

tng ng c trn ht nha. Trong hp th mt khc mt cht tan thng ca ln b mt m khng c hin tng c thay th..1.2. C S Phng Php Trao i ion

L qu trnh trao i ion da trn s tng tc ho hc gia ion trong phalng v ion trong pha rn .Trao i ion l mt qu trnh gm cc phn ng ho hci ch (phn ng th ) gia cc ion trong pha lng v cc ion trong pha rn (lnha trao i). S u tin hp thu ca nha trao i dnh cho cc ion trong pha


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lng nh cc ion trong pha lng d dng th ch cc ion c trn khung mangca nha trao i. Qu trnh ny ph thuc vo tng loi nha trao i v cc loiion khc nhau .

C hai phng php s dng trao i ion l:- Trao i ion vi lp nha chuyn ng , vn hnh v ti sinh lin tc ;

- Trao i ion vi lp nha trao i ng yn ,vn hnh v ti sinh ginon.

Trong trao i ion vi lp nha tnh l ph bin.1.3.Vt liu trao i ion:

Vt liu trao i ion l nhng cht khng ha tan c cha cc ion m cth c trao i vi cc ion khc trong dung dch khi tip xc vi n. Nhng traoi ny din ra m khng c bt k thay i vt l ca vt liu trao i ion. Traoi ion gia dung dch acid hoc base to mui khng ha tan, v iu ny cho

php chng trao i. Ngoi ra cn c cc ion mang in tch dng (trao i

cation) hoc nhng ion mang in tch m (trao i anion) trao i vi cc ioncng du trong mi trng lng.

Hnh 1: a v b l v d c trng cho trao i ion. Cc phn ng trnc xem xt

Vt liu trao i cation c cha nhm in tch m nh sunfat,carboxylate, phosphate, benzoate, vv c c nh vo trc vt cht v cho phpthng qua cc cation nhng t chi anion, trong khi vt liu trao i anion c cha


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nhm mang in dng nh nhm amino, alkyl c th phosphine , alkyl cth sulfua , vv c c nh vo cc trc vt liu v cho php thng qua cc anionnhng t chi cation. Ngoi ra cn c trao i lng tnh c th trao i c cationv anion cng mt lc. Tuy nhin, vic trao i ng thi ca cc cation v anion

c th c thc hin hiu qu hn trn ct hn hp c cha mt hn hp caanion v nha trao i cation hoc i qua cc dung dch x l thng qua vt liutrao i ion khc nhau. C mt cp khc ca b trao i ion c gi l trao iion cht to phc. Nhiu ion chp nhn cp electron t cc ligand thit lp ktcng ha tr nh lin kt. Ty thuc vo s lin kt iu phi, ligand c gi lmonodentate, bidentate, hoc polydentate. Tng tc phi hp l rt c th. Mt vd v mt hp cht phi hp l s phi hp ca mt ion kim loi vi ethylenediamine tetra acetic acid (EDTA) .

Hnh 2: S phi hp ca mt ion kim loi vi ethylene diamine tetraacetic acid (EDTA)

Cu trc hu c ca cc nhm chc nng thng c cha nit, oxy, v ccnguyn t lu hunh, l nhng yu t ca electron (Hnh 3).


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Hnh 3: Cc nhm chc nng cha oxy nh cung cp electron

Nhiu cht t nhin nh protein, cellulose, cc t bo sng v cc ht tc c tnh trao i ion ng vai tr quan trng trong cc qu trnh trong t nhin.

Vt liu trao i ion tng hp da vo than v nha phenolic u tin c gii thiu s dng trong cng nghip 1930. Mt vi nm sau bao gmnha polystyrene vi nhm sulphonate to trao i cation hoc cc nhm amin to thnh b trao i anion c pht trin. Hai loi nha vn l nha thngdng nht hin nay. S ra i ca nha trao i ion hu c tng hp vo nm1935 l kt qu ca s tng hp cc sn phm ngng t phenolic c cha mttrong hai nhm sulfonic hoc amin c th c s dng cho vic trao i ongc ca cc cation hoc anion.

Mt lot cc nhm chc nng c thm vo s ngng t, b sung polymec s dng nh cc cu trc xng sng. xp v kch thc ht ckim sot bi iu kin trng hp v thng nht cng ngh sn xut kch thcht. n nh vt l v ha hc c iu chnh v ci thin Theo kt qu canhng tin b, nhng trao i v c (khong sn, greensand v zeolit) c gnnh hon ton thay th bng cc loi nha ngoi tr mt s ng dng phn tch vchuyn ngnh. Tng hp Zeolit vn cn c s dng nh sng phn t.

Phn loi vt liu trao i ion


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Hnh 4: phn loi vt liu trao i ion

Gm c 3 loi chnh :

- Vt liu trao i ion t nhin: vt liu trao i ion hu c t nhin, vt liu traoi ion v c t nhin.

- Vt liu trao i ion bin i t nhin

- Vt liu trao i ion nhn to: vt liu trao i ion hu c nhn to, vt liu traoi ion v c nhn to

1.3.1 Vt liu trao i ion t nhin

1.3.1.1.Sn phm hu c t nhin

Mt s vt liu hu c t nhin c tnh cht trao i ion hoc c th ctrao cho n bng cch x l ha hc n gin. T bo thc vt v ng vt hot

ng nh trao i ion nh s hin din ca nhm carboxyl protein lng tnh.Nhng nhm carboxyl, (-CO2H), v cc nhm phenolic, (-OH), l yu tnh axit vs trao i cc ion hydro ca n cho cc cation khc trong iu kin trung tnhhoc kim. Cc humins v axit humic c tm thy trong t nhin t "mn" lnhng v d ca trao i lp ny; cc sn phm thc vt mt phn b h hng v

b oxy ha cha cc nhm axit. Mt s sn phm hu c c bn trn th trngl da trn x l cellulose, hoc dng si s dng trong ct trao i ion hoc


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giy lc cho s phn ly trao i ion trn giy. Nhiu trao i ion c lm tvt liu t nhin khc nh g, si, than bn v than bng qu trnh oxy ha viaxit nitric hoc tt hn na, vi axt sulfuric m c khi nhm axit mnhsulphonic acid, (-SO3H) c a vo vt liu. Qu trnh th hai c bit thnh

cng hn vi than sulfonat ha. y c th trao i trong dung dch axit, bi vnhm trao i chnh n b ion ha di nhng iu kin ny, trong khi cc nhmcarboxylic v phenolic yu l khng. Tt c cc ti liu ny c nhc im nhtnh; Tuy nhin, c xu hng mu sc th c cc gii php c x l, vthuc tnh ca n kh khn ti to v kh khn trong vic kim sot x l m nc a ra.

1.3.1.2Sn phm v c t nhin

Nhiu hp cht khong thin nhin, chng hn nh t st (v d, bentonite,

kaolinite, v illit), ct, v zeolit (v d, analcite, chabazite, sodalite, vclinoptilolite) thuc tnh trao i ion trin lm. Zeolit t nhin l nhng vt liuu tin c s dng trong qu trnh trao i ion. Vt liu t st thng c sdng lm vt liu lp hoc m vt liu cho cc ni x l cht thi phng x vtnh cht trao i ion ca n, thm thu thp, v d tnh kh thi. t st cng cth c s dng trong hng lot qu trnh trao i ion nhng thng khng phhp vi hot ng ct v cc tnh cht vt l ca n hn ch dng chy thng quact.

1.3.2 Bin i t nhin trao i Ion ci thin kh nng trao i v chn lc, mt s trao i ion hu c t nhinc thay i; v d, cellulose da trn trao i cation c th thay i thnh

phosphate, carbonic, hoc cc nhm chc nng c tnh axit khc.

Cc thng s hp th ca vt liu t nhin c th c sa i bi mt cht hahc hoc x l nhit; v d, bng cch x l clinoptilolite vi mt dung dch longca axit hoc mt s mui, mt hnh thc c chn lc cc cht hp th c th c

pht trin thnh mt ht nhn phng x c bit.

Ti Nht Bn khong cht t nhin c x l bng dung dch kim trong iukin thy nhit c a ra cho hp th ca cesium v strontium t dung dch.

Nhng phng php iu tr cung cp ti liu vi h s phn phi 1000 n10000. Kt qu tt hn c bo co t vic loi b cc cesium v strontiumthay i bng t st neoline vi acid phosphoric


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1.3.3 Vt liu trao i ion nhn to

1.3.3.1. Ion trao i hu c nhn to

Nm 1935, hai nh ha hc Adams v Holmes ti Phng th nghim ha hc quc

gia Teddington, chng minh rng nhiu loi nha trao i ion hu c c thc tng hp trong mt cch tng t nh loi nha cng c xc nh"Bakelite", c chun b bi Baekeland vo nm 1909. "Bakelite" l mt khkhn, khng ha tan nha polymer ngng t v c th c d dng thc hin

bng cch nung nng cng phenol v formaldehyde, trong s hin din ca axithoc base vi vic loi b nc. V c bn cc phn ng xy ra trong hai giaion

Hnh 5: C ch hnh thnh ca Bakelite

Vic lp li cc phn ng thm nc s to ra mt cu trc ba chiu c cha -OHphenol axit yu hoc OR nhm (hnh 6).


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Hnh 6: polymer Cross-lin kt ca phenol v formaldehyde.

Adams v Holmes ch ra rng nhng trao i ion hydro trong dung dchkim; h cng chun b trao i cation lm vic trong dung dch axit bng cch

a cc nhm axit sulphonic axit mnh, -SO3H, vo cu trc. iu ny cthc hin bng cch sulphonation sn phm cui cng hoc bng cch s dngnh nguyn liu u khng phi l mt phenol m l mt axit phenolsulphonic,trong nhm axit sulphonic hin din.

Bng mt s sa i ph hp tng hp ca h, h cng c th gii thiu ccnhm c bn xut pht t amin v chun b trao i anion tng hp. Ln utin ngi ta c th to vt liu c th kim sot c hai nha trao i cation vanion , hnh vi v s n nh trong s l ng k trc cc vt liu khc.

Cho n khi s pht trin ca k thut hin i ca ha hc polymer cao, nhangng t c s dng thnh cng. Nm 1944 d'Alelio, ti Hoa K, sn xutvt liu cao cp. Nha D'Alelio, cng nh hu ht cc con chu ca h, da trnmt mng li ba chiu thng xuyn hnh thnh bi trng hp benzen styrene

phi sinh (xem hnh 7).

Hnh 7: Styrene


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Cc lin kt i trong chui bn c th c m v cc n v lin kt styrene tu n cui cung cp cho cc chui polymer (Hnh 8).

Hnh 8: Polystyrene

y, cc n v lp i lp li da trn cc phn t styrene xy ra hng triu ln.Styrene cng c th c coi l mt dn xut ca ethylene, trong mt nguynt hydro c thay th bi mt nhm phenyl, -C6H6. Cng nh ethylene c thc polymer ha thnh polyethylene (polythene), styrene sn sng polymerho thnh polystyrene. Cc chui c th c lin kt vi nhau thnh nhngcu trc hai v ba chiu nu styrene c trn vi mt t l nh divinyl benzen(hnh 9) m ging nh styrene trong thuc tnh ca n c hai chui bn khng boha thng qua n c th polymer ha.

Hnh 9: Divinyl benzene

cc polymer hnh thnh t mt hn hp ca styrene v divinyl benzen bao gmchui nh cp trc y, lin quan n mt chui mi lc mi ni cc nv l mt phn t divinyl benzen thay v styrene (Hnh 10).


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Hnh 10: polymer ca divinyl benzen

cc khu vc c bao bc bi cc ng dy b hng chui lin kt vi nhau,v nu chng ta tng tng xy ra trong ba chiu n rt d dng thy rng

polymer kt qu s to thnh mt mng li kh thng xuyn (Hnh 10). Cc lin

kt gia cc chui c gi l "lin kt cho", v nha thng thng c ctrng bi t l divinylbenzene (DVB) c s dng trong chun b ca n; do ,2 phn trm nha lin kt ngang cha 2 phn trm ca DVB v 98 phn trm castyrene.

D'Alelio chun b nha nh vy bng cch trng hp nh tng, s dng cht nhho ph hp, t lng nh ht nha hnh cu. Cc polymer t n khng lm vicnh trao i ion, m n c th c sunfonat ho ch nh th cc loi nha ngngt, gii thiu cc nhm axit mnh, nh SO3H, vo vng benzen ca polymer. Cc

ion hydro ca nhm ny s trao i vi cc cation khc trong dung dch.

Lun nh rng mt vng benzen c lp i lp li nhiu ln trong sut polymer,nhng bc c bn trong gii thiu ca cc nhm trao i (hoc nhm "chcnng" nh h thng c gi l) c th hin trong trao i hnh cation (a) vtrao i anion (b ) (Hnh 11).


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Hnh 11: (a) trao i cation; (b) trao i anionTh hai ca nhng phn ng ny cho mt mui amoni bc bn, c ion hamnh m, v c d dng chuyn i cc c s tng ng. Cc anion sn sngtrao i vi cc anion khc tt c cc gi tr pH. Cc cation l mt phn ca mtchui polymer ha tan hoc mng li, do trao i ni chung khng ha tantrong nc.

Cc trao i ion tng hp nh nha polystyrene nu trn, to thnh nntng ca hu ht cc loi nha hin nay vi mc ch thng mi, c nhiu li th

hn trao i hu c t nhin trc :

- Phng php tng hp c hn kim sot, v sn phm cui cng l thngnht hn trong kch thc ht, mc lin kt ngang, v ni dung ca cc nhmchc nng;

- Bng cch bin i cc yu t thch hp mt lot nhiu loi sn phm khc nhauc th c chun b;

- Cc sn phm c hnh cu, khng ging nh cc ht khng u hnh thnh khi

khi rn nha ngng t c nghin v sng lc. iu ny gim thiu cht thi;Ngoi ra, ht hnh cu ng gi thng nht hn vo ct hn so vi cc ht hnhdng bt thng. iu ny nh hng n cc kiu dng chy ca cc cc gii

php thng qua cc ct v lm cho n d dng hn kim sot hnh vi ca mnh;

- S n nh vt l v ha hc ca cc loi nha c cp trn nh ca loi nhangng t.


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1.3.3.2 Vt liu trao i ion v c nhn to:

Mt vi ng dng quan trng ca nhng trao i ion v c l:

- Ly thn cc ion kim loi

- Ly cc hp cht hu

- Loi b cc cht thi v nhim khng kh

- Chun b cc in cc chn lc ion

- Chun b thn nhn to my

- Chun b cc t bo nhin liu

Tm quan trng ca phn tch trao i ion v c tng hp hin nay c thit lpcht ch. Vic xem xt cc trao i ion trong ha phn tch cho nm 1970 bao gm

bo co kt qu quan trng; nhng tin b r rng trong hai nm qua l trong lnhvc trao i ion v c. Thm ch ngy nay tuyn b ny l gn ng nh vy.

Trao i ion tng hp c th c phn loi trong cc loi sau:

- zeolit nhn to

- mui axit Polybasic

- oxit ngm nc

- Kim loi ferrocynides

- Vt liu trao i ion ha tan

- Hetropolyacids

Zeolit nhn to

Zeolit l cc vt liu v c u tin c s dng cho vic loi b cc cht

nc thi vi quy m ln. Zeolit l tinh th alumin silicat vt liu v c th cchun b nh vi tinh th dng bt, vin hoc cc ht. u im chnh ca zeolittng hp khi so snh vi zeolit t nhin c iu , n c th c thit k rngMu . Naushad: Ion Exchange Letters 2 (2009) ngy 01 ngy 14 thng 3 nhiu tnhcht ha hc v kch thc l rng, v n c n nh nhit cao nhng cmt s hn ch.


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Nhng hn ch chnh ca zeolit nhn to l:

- Chi ph tng i cao so vi zeolit t nhin

- n nh ha hc gii hn phm vi pH cc oan (cao hoc thp)

- Ion c trng l d b can thip t cc ion kch thc tng t

Cng sut x l thc t thu c vi cc zeolit l thp hn so vi cng sut ti aca n k t khi ct c thay i trong giai on u ca mang tnh t ph v

bi v cc dng thi thng cha cc ion khc s chim mt s v tr trao i v do lm gim kh nng x l. Trao i ion da trn silica tng hp c sn xutcho mc ch k thut bng cch nung chy soda, kali cacbonat, fenspat vkaolinit (Schmaltz permutite) v sau dng dung dch sunfat nhm c cha natrisilicat kt ta vi dung dch natri hydroxit (Gel permutite). K t , zeolit tinh

th nhn to cng c tng hp thnh cng.

Cc c tnh c li ca b trao i ion tinh th silicat da trn trao i ionnha tng hp hin i nh sau:

- t nhy cm vi nhit cao hn

- Cu trc Cng v ng u

- C chn lc hn v ph hp tch cc ion trn c s ca h kch c khc nhau

Mt s trong s by gi cng c s dng nh sng phn t hoc ion. Ti n, mt cuc iu tra c h thng c thc hin nh gi hiu sut cazeolit tng hp c sn ti a phng cho vic loi b cc cesium, strontium vthorium t gii php. Cc zeolit sau khi trao i vi cesium, strontium hocthorium, c x l nhit sa cha cc ion thnh cng trong cng mt matrn.

Mui axit polybasic

Mui axit ca kim loi a ha tr c hnh thnh bng cch trn oxit axitkim loi thuc IV, V v VI nhm ca bng tun hon. Mui axit ca kim loi hatr bn c nhm ca lp ny nghin cu nhiu nht. h l cc k khng ha tan.Thnh phn ca chng l khng stochiometric v ph thuc vo cc iu kin theo h c kt ta. Cc ti liu c tng hp cho n nay bao gm pht pht,asenat, molybdat, tungstat, antimonates, silicat, vanadate, v tellurates cazirconium, titan, thori, thic, xeri, crom, st, niobi, tantali, vv..


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Oxit ngm nc

Cc oxit ngm nc ca mt s ion kim loi cng c cc vt liuc thit lp cho mc ch trao i ion. Oxit kim loi ha tr ba kt ta rt hiuqu trong lnh vc ny, v d nh oxit st ngm nc v st hydroxit d dng hp

th cc cation kim th theo lut tc dng khi lng, cc cation ha tr hai khcc hp th trn pH 7. Trong qu trnh ny, cc kim loi kim v t kim chp ph trn b mt v c d dng tch ra trong khi cc cation tch in caohn Ce (III), Y (III), Pm (III), Ru (IV) s lng ln v ch tch ra vi khi khkhn . Cc trao i ion ca lp ny cho thy mt hnh vi lng tnh ph thuc vo

pH ca dung dch. Qu trnh ny c th c m t bi cc im cn bng sauy.

Oxit km cng cho thy tnh cht trao i lng tnh. Oxit pha trn c th sn

sng trong cation th hai cao hn so vi cc cation m c a vo cu trc.Kt qu l li in tch dng c cn bng hin din ca cc anion khc hn loxit v hydroxit. V d nh vt liu bao gm Zn(OH)2trong Zn

2+l mt phnthay th bng Al3+v Al(OH)3c cha Si

4+, Ti+hoc Zr2+. Cc cng thc chungZnn-aAL(OH)2Xnv ALn-1Mn(OH)3 Xn-1, ni M

4+l mt oxit tetravalent v X lmt anion n tr. Oxit kim loi ha tr bn cng thng c s dng nh traoi ion v c nh SnO2, SiO2, ThO2v ZrO2. Trn thc t cc ti liu ny khngc cng thc oxit n gin nh nu trn tr khi chng c t chy nhit cao. Chng c pht hin c cha lng nc khc nhau, m khng phi l c

mt nh l nc hydrat ha t v si m, n b mt lin tc trn mt phm vinhit . Do cc xit ny thng c m t nh oxit ngm nc.

Kim loa Ferrocyanides

Ferrocyanides kim loi khng ha tan cng c th c s dng nh traoi ion v c. H cng c bit n nh ngi nht rc cho kim loi kim. N cth d dng sn sng v hu ch trong vic tch cc cht thi phng x v cc vtliu phn r ht nhn vi t thit hi cho bc x hn cc b phn hu c ca htruy cp. Baetsley et al. Nghin cu molybdate ferrocyanide v xc nh cu trcca n bi cc nghin cu X-ray. N cng s dng molypden v vonframferrocyanides cho vic tch Cs-137 v Sr-90 t cc sn phm phn hch trong mitrng axit. Amine kim loi da ferrocyanides cng nhn c s ch . Hln u tin c gii thiu bi Hahn v Clein, ngi chun b mt ferrocyanidecoban amin. ferrichydroxit cng nhanh chng pht trin cc ng dng trong


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vic tch cc ion kim loi v n c s dng nh mt vt liu hp ph loib asen t nc t nhin.

Vt liu khng ha tan ion trao i

Vt liu trao i ion khng ha tan khc nhau. Mt s lng ln cc hpcht nh vy c xy dng. Nhng vt liu ny c xy dng bng cchkt ta t dung dch mui kim loi vi Na2S hoc H2S. Cc tnh cht trao i ionca sulfua khng ha tan (v d Ag2S, SNS, cus, PBS, FeS, NiS, As2S3, Sb2S3) c nghin cu. Sulfua c chn lc i vi cc cation to thnh sulfua khngha tan. Cc phn ng trao i xy ra thng qua phn ng metathetical trong kim loi ca sunfua c thay th bi ion thch hp t dung dch. Hp th lngca TI +, Ni2+, Co2+, Mn2+, Cu2+v Pb2 c ghi nhn v ZnS, CdS v PBS,Uranium trn PBS, tch Cu2+t Zn2+v Cd2+v SnS v kim loi qu v CuS.

Acid Teropoy

Mui heteropolyaxit c th c s dng nh trao i ion v c. Nhmny rao i c ngun gc t 12 heteropolyacids ca HnXY12O40.nH2O cng thcchung trong X c th P, As, Si, B hoc Ce v Y c th l mt c yu t nhMo, W hoc V. Cc hp cht heteropoly c bit l cc hp cht 12-molybdo ltc nhn oxy ha kh mnh. Cc trao i ca loi ny l n nh trong axit va

phi tp trung. Tuy nhin, h ha tan trong dung dch kim. Cc heteropolyacidsth hin i lc cao vi kim loi nng kim, thori v bc. Kch thc ca cc ionunivalent ca nhng yu t ny l ph hp duy tr vi n trong mng tinh thca heteropolyacids. Ngoi cc mui heteropolyaxit, nhiu cht khc nh muihn hp cng c tng hp v nghin cu chi tit cho cc thuc tnh trao iion. N c tm thy rng mui kp hoc mui hn hp ca cc ion kim loic tnh cht trao i ion khc vi mui n gin. Thng thng, thy u th hnmui n gin ch yu ba kha cnh: nhit tt hn v n nh v mt ha hc,th hai c chn lc trong t nhin v kh nng trao i ion l cao hn so vimui n gin ca n. l vi quan im ny, s ch c a ra tnghp v nghin cu cc tnh cht trao i ion ca cc lp trao i ion. m t mtcht mi nh l mt trao i ion v c, tin ch ca n trong cc lnh vc khcnhau v gii hn ca n, cc thuc tnh sau y c th c nghin cu theo th tnht nh u tin.

- Kh nng trao i Ion

- Ha cht v n nh nhit


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- Thnh phn

- Chun pH

- Cc nghin cu cu

- Chn lc

- ng dng phn tch

Bn cnh cc ng dng, ion v c trao i c mt s hn ch:

- Kh nng trao i tng i thp

- bn c hc tng i thp

- Kch thc l rng khng th kim sot c

- Clay khong sn c xu hng peptize (ngha l chuyn i mu keo)

- Zeolit rt kh kch thc c hc

- Phn hy mt phn trong axit hoc kim

- Hn ch ha cht n nh trong nhiu cc gii php

- Cn mt cht ha hc hoc x l s b trc (c bit l nhng c hm lngmui rt thp)

1.4. Nha trao i ion

L cc polyme c kh nng trao i ion c bit bn trong polymer vi ccion trong dung dch c truyn qua chng. Kh nng ny cng c nhn thytrong cc h thng t nhin khc nhau nh t v cc t bo sng nhau.L mt loi

polymer c kh nng trao i nhng ion c th ca n vi cc ion khc hin dintrong dung dch chy qua ct phn ng. Vt liu trao i ion tng hp c sdng ph bin l nha polystyrene vi nhm sulphonate c kh nng trao i ion

dng v nhm amine trao i ion m. Cc loi nha tng hp c s dng chyu tinh sch nc, ngoi ra cn nhiu ng dng khc bao gm vic phn tchcc yu t ln trong dung dch.


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Hnh 12: Ht nha ion

1.4.1 V cu to:

Ht nha ny c cu trc d th gm hai pha: vng ng cha mngpolymer v nc (hnh cu nh) v vng khng gian cha nc gia cc ht cunh. Cc ion khuch tn trong nha dng xp ln trc ht trong khong khnggian gia cc ht cu nh v v vy tr lc tng th ca chng nh hn nhiu sovi khuch tn trong dng gel.

Mt nhm chc trong mt n v th tch ca loi m quan ln thp hnso vi dng gel v v vy lng ha cht dng ti sinh cng ln hn.Mt cu trc khc thng dng ca vt liu trao i ion l mng trao i ion. Vicc cht kt dnh thch hp ngi ta ch to ra cc cu hnh khc nhau: dng

phng, dng cun. Chng c ng dng trong vic tch cc ion, tch cc phn ttrung ha, ng dng trong k thut in thm tch lm nc ngt.

Mng polyme c tnh k nc, ngc li cc nhm chc trong mng li ctnh a nc. Nha trao i ion khng tan nh cu trc ba chiu ca mng, ncng khng tan hu ht trong cc dung mi. Nha trao i ion c do v trngn khi ngm dung mi, n c xp kh ln. L ca n c kch thc khng u

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