Quá trình hình thành màng Cellulose acetate bằng phương pháp đảo pha và ứng dụng trong công nghệ tinh khiết khí thiên nhiên

CONG BO CONG TRiNH NGHIEN CLfU KHOA HOC TAP CHI TTKH&CN<br /> <br /> <br /> QUA TRINH HJNH THANH MANG CELLULOSE ACETATE BANC PHI/ONG PHAP DAO PHA<br /> VA IJfNG DUNG TRONG CONG NGHE TINH KHIET KHJ THIEN NHIEN<br /> Huynh Ngpc M i n ' , La Thj Thai Ha'<br /> <br /> TOM TAT<br /> <br /> Hinh thai va kich thUdc Id xd'p cua mang Cellulose acetate cd the duac kiem soat bdi<br /> phuang phap dao pha Udt hoac dao pha khd-Udt. Anh hudng ciia nhu'ng thdng sd nhu thanh<br /> phin cua dung dich polymer, thdi gian phai khd trUdc khi mang duac ngam trong be trao ddi<br /> da duac tim hieu. NgUdi ta tha'y rang trang phuang phap dao pha Udt, viec bd sung nhdng<br /> dung mdi phij tra cd ai lUc thap ddi vdi nUdc lam tri hoan qua trinh tach pha cua dung dich tao<br /> mang trang be trao ddi, dieu nay giijp tao ra mang bat dd'i xdng gdm mdt Idp xd'p day va mdt<br /> Idp rat mdng hoan toan khdng chUa Id xdp. Chiing tdi sudung Butanol-1 nhu mat dung mdi<br /> phij tra dekiem soat be day cua Idp mdng khdng chiia Id xd'p.<br /> <br /> ABSTACT<br /> <br /> Flat membranes with controlled morphology, pore dimensions were prepared by wet<br /> and dry-wet phase inversion from cellulose acetate (CA). The effects of several parameters<br /> such as composition of the polymer solution, exposure time before immersidn in the<br /> coagulation bath, were studied. It was found that addition of ex-solvent has a law affinity for<br /> non-solvent caused the delayed demixing of casting solution in coagulation bath and formed<br /> porous asymmetric membranes with a defect-free thin top-layer. Butanol-1 was used as the<br /> ex-solvent in casting solution, water was used as the non-solvent. With increasing amount of<br /> butanol-1 in the casting solution, the increase in skin layer thickness was observed and then<br /> lead to a good separation performance of these membranes.<br /> <br /> TCr khda: Cellulo acetate membrane. Polymeric Membranes for Gas Separation<br /> Processe.<br /> <br /> I.GldlTHIEU<br /> So tach loai hdn hdp khi bang mang morrg la mot ITnh voc nang ddng va phat trien rat<br /> nhanh. Mang dugc sO dung de tach hdn hdp khi nhd tinh tham khac nhau cua cac thanh<br /> phan trong chung. Qua trinh tach khi bang mang mang lai nhieu thuan ldi nho sO dung it<br /> nang IOdng, dau tu vdn thap, yeu cau ddn gian va d i van hanh. Vi vay, cdng nghe nay da<br /> gianh dUdc vai trd quan trgng trong cdng nghiep vi tinh kinh te cua nd. Chung ta deu biet<br /> chat khi chiem giO vj tri trgng tam treng nganh cdng nghiep san xua't nhien lieu hda hgc. Do<br /> dd, so phat trien cua mang tach khi se mang lai nhieu ldi ich kinh te. NhOng nghien cOu<br /> trodc day da chOng minh dOdc tinh hieu qua trong viec sO dung nhOng mang lam tO vat lieu<br /> polymertrang thai thuy tinh nhu polyimide detach hdn hdp khf CO2, CH^, mang polysulfone<br /> de tach khi H2, mang Cellulo acetate dOdc sO dung de leai CO2, HjS ra khdi hdn hdp khi<br /> <br /> <br /> ' Ky su' vat lieu Polymer, Dai hoc BKTPHCM<br /> ' Tien si La Thi Thai Ha, Khoa Cong nghe Vat lieu, Dai hpc BKTPHCM<br /> <br /> <br /> Sol (001) 'Nam thd 1 '' ' Wj<br /> TAP CHI TTKH&CN . CONG BO CONG TRINH NGHIEN CLfU KHOA HOC<br /> <br /> <br /> thien nhien[1]. Vdi nhOng qudc gia cd the manh v i khai thac khi thien nhien thi viec day<br /> manh nghien cOu cdng nghe tinh khiet khi thien nhien bang mang tach khi la mot van de rat<br /> quan trgng.<br /> Cellulose acetate cd do b i n cd ly cao, khang hda tdt va nhiet do chuyen thuy tinh kha<br /> cao nen chung dOdc sO dung rgng rai trong viec tao ra mang lgc Ong dung trong lgc node,<br /> xO ly node thai va tach cac hdn hdp khi. Mang bat ddi xOng de tach khi gdm 2 idp: mot Idp<br /> toplayer mdng khdng chOa Id xdp va mot Idp cd cau true xdp day de trd loc cho idp mdng<br /> tren. Mang bat ddi xOng dOdc tao ra bang phOdng phap dao pha ket tua ngam gdm dao pha<br /> Udt va dao pha khd-Odt[2-5]. PhUdng thOc chung de tao mang bat ddi xOng la ke't hdp qua<br /> trinh tri hoan tach pha vdi qua trinh tach pha long-long tOc thdi.<br /> Trong bai bao nay, chung tdi tap trung nghien cOu nhOng yeu td anh hodng den qua<br /> trinh hinh thanh mang bat ddi xOng thdng qua 2 phOdng phap la dao pha Odt va dao pha<br /> khd-Odt.<br /> Trong phOdng phap dao pha Odt, he {polymer, dimethylformamide, nOdc}xay ra qua<br /> trinh tach pha long-long tOc thdi[6]. Do dd, chung tdi xem xet hieu qua tri hoan tach pha khi<br /> SLf dung hdn hdp dung mdi gdm Dimethylformamide(DMF) va Butanol"' nham tao ra mang<br /> batddixOng.<br /> Trong phOdng phap dao pha khd-Odt, sCf dung hdn hdp dung mdi gdm Dimethyl<br /> acetamide (DMAc) va tetrahydrofuran (THF) de tao mang bat ddi xOng. Qua trinh dao pha<br /> khd, vi THF cd nhiet dp bay hdi thap nen qua trinh THF bay hdi se tao Idp top-layer mdng va<br /> khdng chOa Id xdp. Sau dd, mang dOdc ngam vao nudc, qua trinh dao pha Odt xay ra so trao<br /> ddi giOa DMAc va node. So trao ddi nay se tao ra Idp xdp trong cau true mang bat ddi xOng.<br /> 2 THUG NGHIEM VA CAC THIET B! KHAO SAT<br /> 2.1 Nguyen lieu<br /> Cellulose acetate (CA) cdl\/L= 120000, PD = 1.92, Tg = 80°C. Dung mdi sO dung la<br /> DMF, DMAc, butanol-1, THF. Non-solvent la node cat.<br /> 2.2 Qua trinh tao mang<br /> 2.2.1 Tao mang bang phuang phap dao pha Udt<br /> CAdOdc hda tan trong dung mdi DMF hoac hdn hdp dung mdi gdm DMFvabutanol-<br /> 1. Dung dao gat Erichsem (DOc)-Model 360-05146 tao mang cd be day ban dau la 120|jm<br /> len mdt tam thijy tinh. Sau dd, Idp phim dUdc ngam trong be nudc d 25°C. Mang dOdc hinh<br /> thanh sau 30 phut. Sau dd, Idp phim dUdc tach ra va dem di say chan khdng trong 24 gid.<br /> 2.2.2 Tao mang bang phuang phap dao pha khd-Udt<br /> Hda tan CA trong hdn hdp dung mdi gdm DMAc va THF theo tile the tich DMAc/THF<br /> la 90/10. CA chiem 6% khdi IOdng dung djch.<br /> 2.3 Thiet bj khao sat<br /> 2.3.1 Hien vidien tLlquet(SEM)<br /> Cau'truc be mat va mat cat ngang cua mang bat ddi xOng dOdc quan sat bdi thiet bj<br /> SEM (hang san xuat JEOL(Japan)-model JSM-6480LV) bdi cdng nghe cryo-SEM[7].<br /> 2.3.2 Thiet bi do do truyen sang qua mang trang qua trinh hinh thanh mang<br /> ThOc nghiem do do truyen sang qua mang trong sudt qua trinh mang hinh thanh<br /> nham quan sat qua trinh tach pha Idng-idng dudi so hd trg cua thie't bj UV-Vis<br /> spectrephdtoscopy Varian model Carry 100 Cenc'^'.<br /> <br /> So 1(001)'Nam thai<br /> CONG BO CONG TRJNH NGHIEN CLfU KHOA HOC TAP CHI TTKH&CN<br /> <br /> <br /> 2.4 Npi dung nghien cufu<br /> Trong dao pha Odt, khao sat sO thay ddi cau true mang khi sO dung hdn hdp dung mdi<br /> DMF/butanol-1 vdi cac ti le the tfch 90/10, 85/15, 80/20, IOdng CA sO dung la 6% va 8%<br /> khdi lUdng dung djch tad mang.<br /> Trong dao pha khd-Odt, khao sat sO thay ddi cau true mang khi thdi gian bay hdi cua<br /> Idp phim due la 2 phut va 30 phut.<br /> 3.KET QUA VA BAN LUAN<br /> 3.1.Tac dung tri hoan tach pha long-long cua butanol-1 trong dung djch tao mang:<br /> Khao sat do truyen sang trong trOdng hdp chi sO dung dung mdi DMF va trOdng<br /> hdp dung hdn hdp dung mdi theo ti le the tich DMF/butanol-1 la 85/15 ta dOdc ket qua<br /> nho hinh 1.<br /> Hinh 1. Do truyen qua trong qua<br /> -0%biitanol-1<br /> trinh hmh thanh mang (do d bUdc<br /> - 15%biitanol-1 song 700nm) cho he {CA, DMF,<br /> nirdc}va he {CA, DMF/ butanol-<br /> 1(85/15v/v%),ni/6c}.<br /> <br /> 0 5 13 21 29 37 45 53 61time(s)<br /> <br /> Hinh 1 cho tha'y he mang {CA/DMF/nUdc} xay ra qua trinh tach pha tOc thdi vi toe do truyen<br /> sang giam rat nhanh trong 13 giay dau. Trong khi do, he mang {CA, DMF/butanol-1 (85/15 v/v%),<br /> nUdc}c6 su tri hoan qua trinh tach pha long-long vi tdc dp truyen sang giam cham trong nhu'ng giay<br /> dau tien cua qua trinh hinh thanh mang. NhU vay c6 the ket luan viec bd sung butanol-1 se lam tang<br /> thdi gian tri hoan tach pha.<br /> 78tim<br /> <br /> <br /> <br /> <br /> (2e)<br /> ••»• -jiprc „ .. -... . j ^<br /> <br /> <br /> <br /> (2c) (2d)<br /> Hinh 2. Ket qua SEM mat dUdi(2a) va mat tren(2b) cua he mang {CA, DMF, nUdc}; mat dildi (2c),<br /> mat tren(2d) va mat cat ngang(2e) cua he mang {CA, DMF/butanol-1(85/15 v/v%), nUdc}.<br /> <br /> Sol (001) 'Nam thdi<br /> TAP CHI TTKH&CN CONG BO CONG TRJNH NGHIEN CL/U KHOA HOC<br /> <br /> Ke't qua SEM 6 hinh 2 cho thay mang hoan toan xd'p khi chi sCl dung DMF. Khi bo sung butanol-<br /> 1, mang bat ddi xOng dUdc hinh thanh gom mpt Idp top-layer khong chOa l5 xdp (hinh 2d) va mpt Idp<br /> xdp (hinh 2c). Ldp toplayer c6 be day la 4,4 nm,idp xop co be day 78nm (hinh 2e). Ke't qua nay phu<br /> hdp vdi ke't qua tri hoan tach pha d hinh 1.<br /> 3.2 Anh hufdng cua IOdng butanol-1 de'n be day toplayer trong dao pha Udt<br /> Khao sat he mang co CA chie'm 8% khdi IUdng dung dich. Thay ddi lupng butanol-1 them vao<br /> dung dich tao mang va quan sat sU thay ddi be day Idp toplayer.<br /> <br /> <br /> <br /> <br /> (3a)<br /> <br /> Hinh 3. Ket qui SEM mat cat ngang cua he mang {CA, DMF/butanol-1, nOdc}: (3a),<br /> (3b), (3c) lan lOdt co ti le the tich DMF/butanol-1 la 90/10, 85/15, 80/20.<br /> <br /> Ke't qua SEM 6 hinh 3 cho thay rang khi tang lUOng butanol-1 trong h6n hdp dung moi thi be day<br /> toplayer tang. Tuy nhien, lUdng butanol-1 tang cang nhieu thi be day toplayer hau nhU tang them<br /> khong dang ke, dong thdi cau true toplayer trd nen kem dong nha't hdn.<br /> <br /> 3.3 Anh hUdng cCia ham IUdng CA den cau true mang trong dao pha Udt<br /> Ke't qua SEM d hinh 4 va hinh 5 ben dudi the hien cau true cua he mang (CA, DMF/ butanol-<br /> 1 (85/15 v/v%), nudcjvdi CA chiem 6% va 8% khdi IUdng dung dich tao mang.<br /> 4,4 lim<br /> <br /> <br /> <br /> <br /> fBiItt<br /> <br /> <br /> <br /> aa) .J-)) . (4c)<br /> Hinh 4. Mang 6%CA, {4a): mat dUdi, (4b): mat tren, (4c): mat cat ngang<br /> <br /> <br /> Sol (001) 'Nam thdi<br /> CONG BO CONG TRJNH NGHIEN CLfU KHOA HOC TAP CHI TTKH&CN<br /> <br /> <br /> <br /> <br /> ______ ItM<br /> (5aj (5bj (-^c)<br /> Hinh 5. Mang 8%CA, (5a): mat dddi, (5b): mat tren, (5c): mat cat ngang<br /> Hinh 4 va Hinh 5 cho tha'y khi tang ham IOdng CA tO 6% len 8%, be day ldp toplayer<br /> tang them 0.8pm, ddng thdi giam dang ke kich thudc Id xdp tO 50pm xudng cdn gan 1 pm.<br /> 3.4 Anh hufdng cua thdi gian bay hdi den cau true mang trong dao pha kho-Udt<br /> Ket qua SEM Hinh 6 ben dodi the hien cau true mang {6%CA, DMAc/THF(90/10<br /> v/v%), nudc} khi thay ddi thdi gian bay hai cua ldp phim due trUdc khi mang dOdc ngam vao<br /> be node.<br /> <br /> ^ 3,1pm<br /> 1,4 pm<br /> <br /> <br /> <br /> <br /> ^F^^W<br /> <br /> (cav)<br /> <br /> <br /> <br /> <br /> (6c) (6c-)<br /> <br /> Hinh 6. Ket qua SEM (6a),(6b),(6c) lan lUOt la mat cat ngang, mat dddi va mat tren cua mang bay<br /> hdi 2 phut; (6a'),(6b'),(6c') lan lUdt la mat cat ngang, mat dddi va mat tren cua mang bay hdi 30 phut.<br /> <br /> Sol (001) 'Nam thd 1<br /> TAP CHI TTKH&CN CONG BO CONG TRINH NGHIEN CLfU KHOA HOC<br /> <br /> Ket qua SEM hinh 6 cho thay khi tang thdi gian bay hdi tO 2 phut len 30 phut, be day Idp<br /> toplayer tang tO 1,4pm len 3,1pm (hinh 6a va 6a'), kich thudc Id xdp d mat dOdi giam tO<br /> 25pm xudng cdn khoang 0,5pm (hinh 6b va 6b'), ddng thdi lam giam khuyet tat d mat tren<br /> cua mang (hinh 6c va 6c').<br /> 4. KET LUAN<br /> Trong dao pha odt, viec bd sung butanol-1 vao dung djch tao mang lam tri hoan qua<br /> trinh tach pha. Ket qua cua qua trinh tri hoan nay la hinh thanh mot Idp toplayer mdng va<br /> khdng chOa khuyet tat. ThOc nghiem cho tha'y rang he mang {8%CA, DMF/butanol-1 (85/15<br /> v/v%), nOdc}dat dOdc nhOng yeu cau cho mang tach khi nho do ben cd hgc cao hdn do kich<br /> thodc Id xdp nhd hdn, hieu qua tach khi tdt hdn do toplayer mdng hdn va hoan toan khdng cd<br /> khuyettat, Idxd'p.<br /> Trong dao pha khd-Odt, thdi gian bay hdi cua Idp phim due cang lau thi mang ft cau true<br /> xdp hdn va cd khuynh hodng tao thanh mang dac hoan toan.<br /> Xet ve khi'a canh an toan cho mdi trOdng, vdi viec sO dung dung mdi DMF cd nhiet sdi<br /> cao, qua trinh hinh thanh mang hoan toan trong dung dich; do dd, tao mang dao pha Odt<br /> chiem Ou the hdn so vdi cdng nghe tao mang dao pha khd-Odt.<br /> <br /> Dimg dich pohiner<br /> <br /> Dao aat Mang dao pha<br /> <br /> Hon licrp<br /> a khi vio<br /> (CH4, CO2<br /> > Kill con lai<br /> (CH,)<br /> <br /> <br /> Lop ticrluc<br /> (Polyester xop) Q J Khi tham<br /> \>^ qua raaug<br /> ^-^ (CO:)"<br /> Mang tach khi Bom hiu<br /> 'Be trao doi chan khona<br /> <br /> <br /> Hinh 7. Mo hinh ddn giSn ve cong nghe tao mang (hinh ben trai) va he thong tach<br /> khf (hinh ben phdi)<br /> 5.TAI LIEU THAIVI KHAO<br /> [1] Jennifer Chih-Yi Chen(2002), Evaluation of Polymeric Membranes for Gas Separation Processes:<br /> Poly(ether-b-amide) (PEBAXR 2533) Block Copolymer, Waterloo, Ontario, Canada.<br /> [2] Pinnau, I., Wind, J.,Peineman, K.V., Ind. Eng. Chem. Res., 29(1990) 2028.<br /> [3] Pinnau, 1., PhD Thesis, University of Texas at Austin, 1991.<br /> [4] Mulder, M.H.V., Narderllo, G., Sisto, R, submitted to Gas Separation and Purification.<br /> [5] Mulder, M.H.V., Internal Publication University of Twente, 1988.<br /> [6] Mulder, M.H.V., Internal Publication University of Twente, 1988.<br /> [7] S.s Prakack et a.\.!\/licrostructure evolution in dry cast cellulo acetate membrane by cryo-SEM. Journal of<br /> membrane science 283(2006) 328-338.<br /> [8] Marcel Mulder(1996), Basic Principles of Membrane Technology, Kluwer Academic Publishers,<br /> Dordrecht, Boston, London.<br /> <br /> <br /> 1^ Sol (001) 'Ndm thdi<br />