ti nghin cu k

MC LC 1PHN I : M U

3PHN II NI DUNG

31.1. Gii thiu v bentonit

41.1.1. Cu trc ca bentonit

51.1.2. Tnh cht ca bentonit

51.1.2.1. Tnh cht trao i ion

81.1.2.2. Tnh cht trng n

91.1.2.3. Tnh hp ph

101.1.2.4. Tnh kt dnh

111.1.2.5. Tnh tr

111.1.2.6. Tnh nht v do

111.1.3. ng dng ca bentonit

111.1.3.1. Lm cht xc tc trong cc qu trnh tng hp hu c

131.1.3.2. Lm vt liu hp ph

151.1.3.3. Lm vt liu iu ch st hu c v nanocompozit

151.1.3.4. Dng trong mt s lnh vc khc

161.1.4.Lm giu, lm sch bentonitp:

191.2 . Mc ch v ni dung nghin cu ca lun vn

191.2.1. Mc ch :

191.2.2. Ni dung nghin cu :

20CHNG II : K THUT THC NGHIM

202.1. iu ch ph gia

202.1.1. X l st th:

212.1.2.Bin tnh Bent :

232.1.3.To mng:

25CHNG 3 : KT QU V THO LUN

253.1. Tng hp Bent-CTAB v xc nh iu kin bin tnh khong st.

253.1.1. nh hng ca hm lng CTAB n khong cch khng gian c s ca st.

273.1.2. nh hng ca nhit huyn ph

293.2. Hiu qu ca PVA/Clay

293.2.1. Kh nng tc nc ca mt s mng PVA

KT QU

TI LIU THAM KHO

DANH SCH CC BNG V CC HNH

Bng 3.1 : Cc gi tr khong cch gia hai lp st khi tng hm lng CTAB..26

Bng 3.2. Kt qu kho st nh hng ca nhit huyn ph n gi tr d001 v hm lng cation cetyl trimetyl amoni trong sn phm ..28

Hnh 1.1. Cu trc khng gian mng li ca montmorilonit..4

PHN I : M U

Bentonit l loi khong st t nhin, thuc nhm smectit gm montmorilonit v mt s khong khc. Bentonit c cc tnh cht c trng l trng n, kt dnh, hp ph, tr, nht v do . Do nhng tnh cht ny m bentonit c ng dng t xa xa nh lm gia dng (bt a, ni, chum, vi) v ngy nay c s dng lm cht xc tc , cht to huyn ph trong sn, thuc nhum, phm mu, lm cht hp ph trong x l nc thi , kh giy, mc, lm cht u ch to nanocompozit

St hu c l sn phm ca qu trnh tng tc gia st bentonit v cc hp cht hu c phn cc hoc cc cation hu c, hoc l cc amin bc 1, bc 2, bc 3, bc 4 c mch thng, nhnh v vng . St hu c c tnh cht c bit nh a hu c, nht, hp ph. Do c nhng tnh cht trn m st hu c c ng dng lm cht chng sa lng trong sn, du nhn, mc in...v n cn c th nghin cu to mng tch nc khi ancol. C nhiu cch khc nhau tch nc khi ancol nhng trong trng hp ny chng ta s dng st hu c to mng nh hng cho qu trnh tch nc khi ancol.

ng gp mt phn nh vo vic nghin cu v bentonit v iu ch st hu c t bentonit Vit Nam, trong bo co ny chng ti trnh by nhng kt qu kho st qu trnh ch bin st hu c , sau tin hnh xc nh cu trc v tnh cht ca sn phm st hu c iu ch c to mng PVA/Clay nh hng cho qu trnh tch nc khi ancol .

PHN II NI DUNG

CHNG I. TNG QUAN

1.1. Gii thiu v bentonit

Bentonit l loi khong st t nhin thnh phn chnh l montmorilonit (MMT) v vy n cn c tn l MMT. Cng thc n gin nht ca MMT l Al2O3.4SiO2.nH2O ng vi na t bo n v cu trc. Trong trng hp l tng, cng thc ca MMT l Si8Al4O20(OH)4 ng vi mt n v cu trc. Tuy nhin thnh phn ca MMT lun khc vi thnh phn biu din l thuyt do c s thay th ng hnh ca ion kim loi Al3+, Fe3+, Fe2+, Mg2+ vi ion Si4+ trong t din SiO4 v Al3+ trong bt din AlO6. Nh vy thnh phn ha hc ca MMT ngoi s c mt ca Si v Al cn thy cc nguyn t khc nh Fe, Zn, Mg, Na, K trong t l Al2O3 : SiO2 t 1: 2 n 1: 4 .

Ngoi thnh phn chnh l MMT, trong bentonit cn cha mt s khong st khc nh hectorit, saponit, beidelit, nontronit, v mt s khong phi st nh canxit, pirit, manhetit, mt s mui kim loi kim khc v hp cht hu c.

1.1.1. Cu trc ca bentonit

Cu trc khng gian mng li ca montmorilonit c trnh by trn hnh 1.1.

Hnh 1.1. Cu trc khng gian mng li ca montmorilonit

Trong trng hp l tng, cc nguyn t Si nm tm ca cc t din, cn cc nguyn t Al nm tm cc bt din ca MMT. Do MMT c cu trc 2:1 dng diocta nn cu trc lp ca MMT c hnh thnh t hai l t din lin kt vi mt l bt din gia to nn mt lp aluminosilicat. Gia cc lp aluminosilicat l cc cation c kh nng trao i b hydrat ha. Khong cch gia cc lp trong cu trc c bn ca MMT l 9,6, khong cch ny b thay i t hay nhiu ty thuc vo s lng, bn cht cc cation trao i v lng nc b hp ph, thng c th n 15.

S cu trc khng gian mng li ca MMT hnh 1.1 l cu trc trung ha in. Nu Si4+ tm t din hay Al3+ tm bt din b thay th ng hnh bi cc cation dng c in tch nh hn th cc mng li tch in m. in tch m ca mng li s c b tr bng cc cation mang in tch dng nh Na+, K+, Ca2+, Fe2+, Mg2+... khong khng gian gia cc lp. Cc cation ny c kh nng trao i vi cc cation kim loi hoc cation hu c khc. Nh vy dung lng trao i cation ca MMT tng ng vi in tch ca cc lp.

1.1.2. Tnh cht ca bentonit

1.1.2.1. Tnh cht trao i ion

c trng c bn ca bentonit l kh nng trao i ion do trn b mt ca cc lp st c cc trung tm (O, OH) mang in tch m c kh nng hp ph v trao i cation. ng thi, tnh cht c c l do s thay th ng hnh ca cc cation. V d nh khi Si4+ trong mng t din b thay th bi Al3+ hoc Fe3+, hoc Al3+ trong mng bt din b thay th bi Mg2+, Fe3+, Cr3+, Zn2+..., th s thay th cc ion in tch cao ny bng cc ion in tch thp hn s gy ra s thiu ht in tch dng trong cu trc t din v bt din to ra in tch m trn b mt phin st.

i vi bentonit, s thay th ng hnh ch yu xy ra trong lp bt din, gia hai lp t din ca phin st. Do lin kt ca cation vi b mt lp st l lin kt yu v cc cation c th b thay th bi cc cation khc. Kh nng trao i mnh hay yu ph thuc vo lng in tch m b mt v s lng ion trao i. Nu s lng in tch m cng ln, s lng cation trao i cng ln th dung lng trao i cng ln.

Kh nng trao i ion ca lp aluminosilicat cn ph thuc vo in tch v bn knh ion ca cation trao i. Cation c in tch thp d trao i hn cation c in tch cao:

Me+ > Me2+ > Me3+i vi cation cng in tch, bn knh ion cng nh th kh nng trao i cng ln, c th sp xp theo trt t sau:

Li+ > Na+ > K+ > Cu2+ > Fe2+ > Al3+Tuy nhin kh nng trao i ca bentonit ch yu vn ph thuc vo in tch m b mt v in tch m trong mng li. B mt ca bentonit gm b mt trong v b mt ngoi. Kh nng trao i ion b mt ngoi phn nh kch thc ht tinh th, ph thuc vo s t gy lin kt v khuyt tt b mt. Kch thc ht cng nh th kh nng trao i cng ln. Kh nng trao i ion b mt trong phn nh lng in tch m trn mng li v kh nng hp ph ca bentonit. N ph thuc vo lng cation b tr trong mng li. S lng cation cng ln th kh nng trao i cng ln. Dung lng cation trao i dao ng t 80 n 150 meq/100g. Dung lng trao i anion dao ng t 15 n 40 meq/100g.

S trao i ion ca bentonit cn lin quan n s thay th cc nguyn t hyro trong cc nhm hyroxyl ca montmorilonit. Theo mt s nghin cu th nh ca cc t din SiO2 hng ra ngoi ca lp cu trc, cc nguyn t oxi c thay th bi cc nhm hiroxyl v cc nhm ny m nhim vic duy tr lin kt yu gia cc lp v gp phn vo s cn bng in tch. Ngoi ra trong cu trc ca bentonit cn c cc nhm hiroxyl khc nm nh cc bt din. Trong su nh ca bt din c hai nh l nhm OH cn bn nh kia l oxi, trong nhm hiroxyl ca lin kt Si OH khng c kh nng trao i hiro. Nhm hiroxyl ca lin kt Al OH c tnh axit yu nn kh nng trao i yu. Nhm Si O Al c tnh trao i mnh nn c tnh quyt nh n trao i cation H+.

1.1.2.2. Tnh cht trng n

Khi nc, cc phn t phn cc hoc cc cation b hp ph vo khe trng gia cc lp s lm tng chiu dy lp cu trc, tnh cht ny gi l tnh cht trng n. Mc trng n ph thuc vo bn cht khong st, cation trao i, s thay th ng hnh ca cc ion trong cc lp v s c mt ca cc ion, cc phn t phn cc trong mi trng phn tn. Lng nc c hp ph vo gia cc lp st ph thuc vo kh nng hydrat ha ca cc cation trao i.

Khi bentonit hp ph hi nc hay tip xc vi nc, cc phn t nc phn cc s thm nhp vo bn trong cc lp, lm khong cch ny tng ln t nht 14(15 ty thuc vo loi bentonit v lng nc b hp ph. S tng khong cch d001 c gii thch l do s hydrat ha ca cc cation gia cc lp.

trng n ca bentonit ph thuc vo bn cht cation trao i trn b mt lp st. V d, ion Na+ vi in tch +1 c th lin kt vi mt tm tch in m trn mt lp st. Do vy khi b hyrat ha, bentonit Na c kh nng trng n t khong cch ban u gia 2 phin st l t 9,2 n t nht 17. Trong mi trng kim bentonit-Na b hirat ha mnh hn, lp nc hp ph tng mnh. Do vy trong mi trng kim, huyn ph bentonit-Na rt bn vng.

Cation Ca2+ lin kt vi 2 tm tch in m trn 2 phin st do vy khi bentonit-Ca b hydrat ha, khong cch gia 2 phin st ch tng t 12,1 n 17. iu ny hn ch s trng n hay kh nng to nht ca bentonit-Ca. trng n ca bentonit-Ca t 100 n 150%, i vi bentonit-Na trng n ln hn.

1.1.2.3. Tnh hp ph

Tnh cht hp ph ca bentonit c quyt nh bi c tnh b mt v cu trc lp ca chng. Vi kch thc ht nh hn 2m v c cu trc mng tinh th dng lp nn bentonit c b mt ring ln. Din tch b mt ca bentonit gm din tch b mt ngoi v din tch b mt trong. Din tch b mt trong c xc nh bi b mt ca khong khng gian gia cc lp trong cu trc tinh th. B mt ngoi ph thuc vo kch thc ht. S hp ph b mt trong ca bentonit c th xy ra vi cht b hp ph l cc ion v c, cc cht hu c dng ion hoc cht hu c phn cc. Cc cht hu c phn cc c kch thc v khi lng nh b hp ph bng cch to lin kt trc tip vi cc cation trao i nm gia cc lp hoc lin kt vi cc cation qua lin kt vi nc hoc lin kt vi cc trung tm mang in tch trn b mt cc lp st. Nu cc cht hu c phn cc c kch thc v khi lng phn t ln, chng c th kt hp trc tip vo v tr oxi y ca t din trong mng li tinh th bng lc Van der Walls hoc lin kt hiro. S hp ph cc cht hu c khng phn cc, cc polime v c bit l vi khun ch xy ra trn b mt ngoi ca bentonit .

Do bentonit c cu trc lp v phn tn cao nn c cu trc xp phc tp v b mt ring ln. Cu trc xp nh hng rt ln n tnh cht hp ph ca cc khong st, c trng ca n l tnh chn lc i vi cht b hp ph. Ch c phn t no c ng knh nh so vi l xp th mi chui vo c. Da vo iu ny ngi ta c th dng bentonit hot ha lm vt liu tch cht. y cng l mt im khc nhau gia bentonit v cc cht hp ph khc.

1.1.2.4. Tnh kt dnh

Khi trn vi nc, bentonit s c kh nng kt dnh mnh nn t thi xa xa con ngi bit s dng loi st ny nn thnh cc vt dng nhm mc ch phc v i sng. Li dng tnh cht kt dnh ny, trong cc xng c gang, bentonit c dng lm cht kt dnh v qung bt thnh vin trc khi a vo l nung, hoc lm cht kt dnh trong khun ct c.

1.1.2.5. Tnh tr

Bentonit tr v bn ha hc nn khng c, c th n c. Ngi ta dng bentonit lm cht n trong dc phm, thc n gia sc, m phm, lm cht lc sch v ty mu cho bia, ru vang v mt ong...

1.1.2.6. Tnh nht v do

Do c cu trc lp, c xp cao, c kh nng trng n mnh trong nc nn bentonit c tnh nht v do. Do c cc tnh cht ny m bentonit c s dng lm ph gia bi trn mi khoan, gia c thnh ca l khoan, lm ph gia trong xi mng Portland, ch va v cht dnh kt c bit.

1.1.3. ng dng ca bentonit

1.1.3.1. Lm cht xc tc trong cc qu trnh tng hp hu c

Do c axit cao nn bentonit c th c dng lm cht xc tc trong cc phn ng hu c. B mt ca bentonit mang in tch m do s thay th ng hnh ca cc ion Si4+ bng ion Al3+ tm t din v ion Mg2+ thay th ion Al3+ tm bt din. Cc ion thay th Al3+, Mg2+ c kh nng cho in t nu ti in tch m ca chng khng c b tr bi cc ion dng. Do vy tm axit Lewis c to thnh t ion Al3+ v ion Mg2+ cc nh, cc ch gy nt v cc khuyt tt trn b mt bentonit. Nu lng Al3+ v Mg2+ tng ln b mt bentonit s lm tng axit Lewis ca chng.

Trn b mt bentonit tn ti cc nhm hiroxyl. Cc nhm hiroxyl c kh nng nhng proton hnh thnh trn b mt bentonit nhng tm axit Bronsted. S lng nhm hiroxyl c kh nng tch proton tng ln s lm tng axit trn b mt ca bentonit.

Trong cc vt liu st chng (pillared clays), gia ct chng v cc lp aluminosilicat ca bentonit c nhng lin kt cng ha tr thc s. Cc lin kt ny dn n s gii phng cc phn t nc v proton lm tng axit v bn ha cu trc ca bentonit chng.

Vic bin tnh bentonit bng phng php trao i cation kim loi a ha tr nh Ti4+, Zr4+, Al3+, Si4+,... to ra vt liu st chng c axit v xp cao hn, c kh nng xc tc cho mt s phn ng hu c. V d; vic s dng st chng lm cht xc tc axit rn trong phn ng hu c pha lng thun li hn nhiu so vi axit lng. Sau khi kt thc phn ng ch cn lc hn hp phn ng c th tch cht xc tc rn ra khi hn hp phn ng.

Ngoi ra, do bentonit c kh nng hp ph cao nn c th hp ph cc cht xc tc trn b mt trong gia cc lp. V vy, bentonit c s dng lm cht mang xc tc cho nhiu phn ng tng hp hu c.

1.1.3.2. Lm vt liu hp ph

Bentonit c dng rng ri lm cht hp ph trong nhiu ngnh cng nghip. Trong cng nghip lc du, lng bentonit c s dng vi lng rt ln, bao gm bentonit t nhin v bentonit hot ha. Lng bentonit t nhin tiu tn cho qu trnh lc du l 25% khi lng du v lng bentonit hot ha bng 10% khi lng du. Vic s dng bentonit lm cht hp ph u vit hn hn phng php c l phng php ra kim. Lng bentonit mt i trong qu trnh tinh ch ch bng 0,5% lng du c tinh ch. Ngoi ra, phng php dng bentonit cn c mc hao ph du thp do trnh c phn ng thy phn.

Trong cng nghip ha than, bentonit c s dng tinh ch benzen th v cc bn sn phm khc.

Vi t cch l mt cht hp ph c bit tt, bentonit c th to ra cc dung dch khoan vi cht lng c bit cao v chi ph nguyn liu thp. V th, cng vi s pht trin ca ngnh thm d v khai thc du, lng bentonit c s dng trong vic ch to dung dch khoan ngy cng tng. Ngy nay M, lng bentonit c s dng lm dung dch khoan chim ti 40% tng sn lng bentonit ca nc ny.

Cc chc nng quan trng ca bentonit trong dung dch khoan l:

+ Lm tng kh nng lu chuyn ca dung dch khoan do c nht cao ngay c khi nng cht rn thp.

+ To huyn ph vi cc tc nhn v mn khoan gy lng khi ngng lu chuyn dung dch khoan v mt l do no .

+ Ngn cn s mt dung dch vo cc tng c p sut thp, thm nc nh vic to nn lp bnh lc khng thm nc trn thnh l khoan. Lp bnh lc ny khng ch ngn khi b mt dung dch m cn c tc dng nh mt ci mng cng lm bn thnh l khoan.

Ngoi ra, do c kh nng hp ph tt nn bentonit cn c s dng lm cht hp ph cc cht hu c v du m trong x l mi trng

1.1.3.3. Lm vt liu iu ch st hu c v nanocompozit

Gn y vi s pht trin mnh m ca cng ngh nano, nhiu ngnh cng nghip s dng bentonit ngy cng nhiu. Cng ngh nano s dng st hu c trn vi cc cht khc ch to ra cc vt liu mi. V d, st hu c c trn vi cc polime ch to cc nanocompozit, gi l composit-nano-bentonit. Cc polime c th c trn thm cc ht nanobentonit khi c ko thnh mng s cho mng kn hn rt nhiu so vi polime khng trn v khi ko, cn, cc l nanobentonit ny nm song song vi b mt, c kh nng ngn cn hiu qu nhiu loi phn t i qua. Cc ht nanobentonit ny trn vi polime khng nhng kn m cn bn hn nhiu, do p ng yu cu lm cc ng mm truyn dn thuc, dn mu trong y t.

1.1.3.4. Dng trong mt s lnh vc khc

Mt lng ln bentonit c s dng lm cht n trong cng nghip sn xut vt liu tng hp (x phng, vi si...). c bit trong cng nghip sn xut giy, vic trn thm bentonit lm tng hm lng cao lanh, gim lng xenlulo cn c trong giy, lm tng ng k cht lng v gim gi thnh ca giy.

Trong cng nghip bia, ru, bentonit hp ph cc cht hu c, cc cht bo, cc sn phm ph khng mong mun trong qu trnh ln men, ng thi hp ph c ion st, ng v cc tc nhn gy bnh ca ru, li khng lm mt hng v ca ru, bia.

Bentonit cn c s dng lm sch ngun nc mt. Do bentonit lm kt ta cc vn c, hp ph cc ion gy c, mt lng ln vi khun gy bnh v cht hu c c trong nc vi gi thnh tng i r.

Do c c tnh tr, khng c hi nn bentonit cn c dng lm ph gia trong thuc tiu ha thc n v gip iu tit axit cho ng vt, lm ph gia dc phm.

1.1.4.Lm giu, lm sch bentonit:

Cc m bentonit kim trn th gii thng c hm lng MMT cao, nn cc cng trnh nghin cu v lm giu, lm sch bentonit kim nng cao hm lng MMT-Na ca cc tc gi trn th gii khng nhiu. i vi nhng m bentonit kim c hm lng MMT cao nh bentonit kim Wyoming (M) ngi ta c th trc tip s dng m khng cn qua giai on lm giu, hoc bin tnh n thu c sn phm cho nhng mc ch khc nhau. Tuy nhin i vi loi qung bentonit c hm lng MMT thp - nh bentonit Tuy Phong, Bnh Thun ca Vit Nam, ngi ta phi s dng phng php tuyn trng lc hoc phng php t. Theo phng php ny, bentonit c pha vi nc theo mt t l thch hp. S dng cht phn tn Na(PO3)6 lm lng cc khong phi st theo nhiu giai on, sau huyn ph mn c lc, sy kh v nghin mn thu sn phm. Mt s tc gi khc s dng phng php tuyn thy xyclon, x l nhit v ha hc nng cao hm lng MMT trong bentonit. Trn th gii s lng khong bentonit kim th (cha cc cation Ca+2, Mg+2, ) vi hm lng MMT cao tng i nhiu, nhng dng bentonit kim li mang li nhiu ng dng hn trong nhiu lnh vc, v vy c rt nhiu nghin cu chuyn ha bentonit kim th v dng bentonit kim. Nhng nghin cu ny c t trc nhng nm 1950 ti nhiu nc nh M, Lin X c, ... Ngy nay cng ngh chuyn ha bentonit kim th sang dng bentonit kim c a vo nhiu nh my vn hnh v sn xut ra hng trm nghn tn sn phm cho nhng lnh vc khc nhau, nh Hn Quc mi nm sn xut hn 800 nghn tn sn phm bentonit hot ha cho nhng mc ch khc nhau. Phng php hot ha chuyn bentonit kim th v dng bentonit kim nh sau: qung bentonit kim th c phn cp, p, nghin n c ht thch hp. Sau qung c trn u vi tc nhn hot ha (l cc mui ca natri nh Na2CO3, NaCl, ...) theo mt t l thch hp v nung hn hp trong l quay vi nhit trong khong 300(500oC, sn phm hot ha sau y c ng bao v a i s dng. Mt iu ng lu y l qung bentonit kim th trn th gii thng c hm lng MMT cao nn qung c a vo hot ha ngay m khng qua giai on lm giu, cn i vi qung bentonit kim th Di Linh-Lm ng ca chng ta, do hm lng MMT khng cao (khong 30(40%) nn s dng cho mt s mc ch ch to vt liu st hu c th trc khi hot ha nn lm giu qung nng hm lng MMT.Ngi ta cng s dng cc tc nhn hot ha khc nh axit v c (H2SO4, HNO3, HCl) v cc cht hu c khc hot ha bentonit kim v bentonit kim th nhm thu nhanh cc sn phm hot ha cho nhng mc ch s dng khc nhau.

1.2 . Mc ch v ni dung nghin cu ca lun vn

1.2.1. Mc ch :

Phng php bin tnh khong st Montmorillonite lm vt liu ph hp cho vic to mng PVA/Clay .

1.2.2. Ni dung nghin cu :

t c mc ch nu trn chng ti s thc hin nhng ni dung nghin cu sau:

La chn tc nhn bin tnh khong st

Xc nh iu kin bin tnh khong st

To mng PVA/Clay bin tnh

CHNG II : K THUT THC NGHIM

2.1. iu ch ph gia

Trong bo co ny, chng ti chng ti nghin cu ng dng ca st bentonit (Bent) u lm nguyn liu u iu ch st hu c, st hu c c vit tt l Bent-hu c.

2.1.1. X l st th:

Qu trnh iu ch st tinh gm nhiu giai on

-Mc ch: Nhm loi b hp cht bn v rc.

-Phng php thc hin :

St nguyn khai sau khi khai thc t m v c nghin nh v ngm, khuy trong nc sao cho st c kh nng trng n ti a v tch lp vi cc cht bn khc(ngm trong mt tun), sau li tm, ri gn b nc trong trn thu c huyn ph st.St thu c sch hn st ban u nhiu,em sy kh nhit t 80-100oC ui ht nc v trnh hng st (sy trong 1 ngy ).Thu c Bent x l.

2.1.2.Bin tnh Bent :

a.Trao i vi Na+ :

-Cn 32g Bent x l + 640 ml nc ct hn hp khuy trong 1 ngy. Sau khi Bent c khuy qua 1 ngy bt u cho t t 224ml NaCl 1M vo( nhit phng ),va khuy va cho t t NaCl t hiu qu pha trn tt nht.Sau yn hn hp nhit phng trong vng 24h Bent trao i vi Na+. Hn hp c li tm ,sau dung nc ct ra ht Cl- sau khi trao i Na+ .Lp i lp li cho n khi ra sch Cl- .Th li vi Ag+ bit kt qu.Nc ra sau khi trao i Na+ c gi li tnh lng Na+ trao i. Bent sau trao i Na+ ( ra ht Cl- ) c em i sy trong t sy chn khng 850 C trong 24h.

Tm tt quy trnh :

b.Trao i CTAB:

Bent sy sau khi trao i Na+ c khuy vi nc ct trong 2h gia nhit 600C ( theo t l: c 5g Bent + 200ml H2O). Sau cho t t CTAB vo, khuy v ngm hn hp trong vng 24h. Ly tm hn hp trn v dung nc ct ra sch Br- c trong hn hp,lp i lp li nhiu ln cho n khi Br- c ra ht.(dung Ag+ th kt qu ra ). Sau khi ra sch Br- ,em sy Bent nhit 500C trong 24h, ta c Bent hu c .

Tm tt qu trnh thc hin :

2.1.3.To mng:

a.Mng PVA n gin :

y chng ti to mng PVA 10% nh sau :

Cn 10g PVA ri thm vo 90ml H2O. Dng my khuy t gia nhit 800C khuy hn hp trong vng 6h (trong qu trnh khuy c lp thm sinh hn trnh hn hp b bay hi v cn )

Sau khi khuy hn hp 6h ta vo a thy tinh v em sy trong t sy chn khng 50 0C trong 24 h.Ta c Mng PVA 10% n gin.

b.To mng PVA-Clay:

Khuy dung dch PVA 10% trong vng 6h 800C (ging nh to mng PVA 10%). Cho Bent bin tnh ( trao i Na+ v CTAB trn ) vo hn hp v khuy trong 8h.Sau em sy trong t sy chn khng 500C ta c mng PVA-Clay.

CHNG 3 : KT QU V THO LUN3.1. Tng hp Bent-CTAB v xc nh iu kin bin tnh khong st.

Vi mc tiu tm kim nhng ng dng mi ca st hu c trong cng nghip chng ti tin hnh x l st th v bin tnh chng bng cht hot ng b mt cetyl trimetyl amoni bromua vi t l khc nhau v kho st hm lng st/CTAB thch hp.

3.1.1. nh hng ca hm lng CTAB n khong cch khng gian c s ca st.

Cc mu st c x l trao i vi ion CTA+. Bng 3.1 trnh by 6 mu st hu c c thnh phn CTAB t 0-110% theo khi lng.

Bng 3.1 : Cc gi tr khong cch gia hai lp st khi tng hm lng CTAB

Mu St hu c D001,Ao=(d001-9,6),

Ao

1Bent-CTAB0% 15,53 5,93

2Bent-CTAB30% 16,94 7,34

3Bent-CTAB40% 18,64 9,04

4Bent-CTAB60% 25,03 15,43

5Bent-CTAB100% 25,61 16,01

6Bent-CTAB110% 25,12 15,52

Da vo trn ta c th thy khong cch khng gian c s ph thuc vo hm lng CTAB. Khong cch gia cc lp st tng mnh khi hm lng CTAB tng t 0 n 60%. hm lng cao hn, CTAB dng nh bo ha nn khong cch khng gian c s gn nh khng thay i. Do vy chng ti c nh hm lng CTAB 60% theo khi lng v xem xt cc yu t nh hng khc n khong cch gia cc lp st.

3.1.2. nh hng ca nhit huyn ph

Theo cc cng trnh khoa hc cng b th nhit c nh hng kh ln n qu trnh iu ch st hu c. Nu nhit qu thp th s thm nhp ca cc cation hu c vo bentonit thp. V vy yu t th hai m chng ti tin hnh kho st l nh hng ca nhit huyn ph, t tm ra nhit thch hp cho qu trnh iu ch st hu c t bentonit v CTAB.

Cc mu st hu c c iu ch theo quy trnh nu mc 2.1.2 vi cc iu kin c th nh sau: huyn ph (bentonit v mui amoni hu c) c t l CTAB chim 60% khi lng c iu chnh n pH bng 7 v c khuy trn trong thi gian 24h, tc khuy n nh 500 vng/pht. Nhit huyn ph c bin i t 30 n 90oC.

Bng 3.2. Kt qu kho st nh hng ca nhit huyn ph n gi tr d001 v hm lng cation cetyl trimetyl amoni trong sn phm

Nhit

huyn ph (oC)30405060708090

d001 ()29,12534,21737,19240,05740,16840,62140,953

=(d001-9,6),

Ao19,52524,61727,59230,45730,56831,02131,353

Qua kt qu kho st mc nh hng ca nhit huyn ph n gi tr d001 v hm lng cation amoni hu c trong sn phm, khi khuy trn huyn ph (CTAB v bentonit) c hm lng CTAB chim 60% khi lng trong 24h, pH bng 7, th khong cch lp c bn d001 t gi tr cao bng 40,621. Nu tin hnh phn ng nhit cao hn, th gi tr d001 v hm lng cation amoni cng tng ln, tuy nhin s thay i l khng ng k. Nh vy, nhit thch hp cho qu trnh iu ch st hu c t CTAB v bentonit l 60oC.

3.2. Hiu qu ca PVA/Clay

3.2.1. Kh nng tc nc ca mt s mng PVA

a) Hiu sut ca mng PAAHCI-PVA99 trong qu trnh tch nc khi ethanol cho kh nng tch nc cao .

b)Hiu sut ca mng PVA-bazo cha 10% nc trong nguyn liu.

KT QU

1. x l s b tinh ch betonit thun Na (Bent.Na)

2. kho st mt vi yu t nh hng n kh nng trng n ca st hu c tm ra iu kin thch hp v hm lng CTAB, nhit tng hp st hu c.

3. Kho st kh nng tch nc ca mng PVA/Clay.

TI LIU THAM KHO

Ting Vit

1. Thn Vn Lin, Nghin cu qui trnh x l, hot ho bentonit Vit Nam sn xut bentonit xp, Bo co kt qu nghin cu ti hp tc theo ngh nh th vi Hn Quc, H Ni, thng 5, 2005.

2. Thn Vn Lin v cng s, Lm giu, lm sch v hot ho bentonit Di Linh - Lm ng v bentonit Tuy Phong, Bnh Thun, Hi ngh Khoa hc v Cng ngh ht nhn ton quc ln th VI, Lt thng 10 nm 2005

3.Trn Xun Phng, Nghin cu tng hp bentonit hu c lm cht to cu trc cho dung dch khoan gc du, Lun vn thc s, HQGHN, 2004.

Ting Anh

1.Anatolie Pushniak (2003), Method for acidic activation of bentonite. MD 2 739 F1. 14.01.2003.

2.Bauer Carl (1997), Formulations including improved organoclay compositions, WO 97/09375. 13.03.97.

3 . Charles A. Cody, Edward D.Magauran (1992), Method of treating waste water for organic containminatnts with water dispersible organically modified smectite clay compositions, US Patent 5,130,028, Jul.14, 1992.

4. Chuen-Shyong Chou, Dennis Paul Lorah, Aqueous nano composite dispersions, US 2002/0086908 A1, Jul.4, 2002.

5. Emmanuel P. Glennelis, Composite of high melting polymer and nanoclay with enhanced properties. US 2005/0137287 A1. Jun. 23, 2005.

Nguyn Hu Dng

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