TAP CHI HOA HOC T. 49(2) 133-137 THANG 4 NAM 2011
T 6 N G H O P V A D A C
TRl/NG VAT LIEU SBA-15 CHIJC NANG HOA NHOM THIOL:
A N H H U ' 6 ' N G C O AHAM LirONG
N G U 6 NCUNG CAP
NHOM THIOL
Tran Thj Thu Phuong, Vo Vien Khoa Hda hgc, Trudng Dgi hgc Quy Nhan
Din Tda soan 5-11-2008
Abstract
Thiol-functionalized mesoporous silicas have been synthesized by co-condensation of 3-mercaptopropyl- trimethoxysilane (MPTMS) and tetraethoxysilane (TEOS) in acidic medium with the block copolymer Pluronic 123 as a structure directing agent. The influence of the molar ratio MPTMS/(TEOS+MPTMS) on the textural properties has been investigated. The products were characterized by low-angle XRD, nitrogen adsorption-desorption, TGA, transmission electron microscopy, and elemental chemical analysis. The results show that the amount of thiol incorporated to the materials is in accordance with the MPTMS/(TEOS+MPTMS) proportion in the reaction mixture but increasing incorporated thiol leads to a reduction of the textural and structural properties of materials.
l.MdDAU
Vdo ddu tliap nien 90 ciia the ky trudc, nhung thdnh cdng trong viec su dung cdc chdt boat ddng be mat nhu nhirng chdt djnh hudng cdu true de tong hgp cdc vat lieu mao qudn trung binh da md ra mdt giai doan mdi trong tdng hgp chat xiie tdc vd hdp phu [1].
Vai nam sau do, cdc nha khoa hgc nhom G. D, Stucky da phdt hien ra viec dimg cdc polyme nhu nhirng chdt djnh hudng cdu true vd da tong hgp thanh cdng hg vat lieu SBA (Santa Barbara Amorphous) [2]. Cdc vat lieu ndy cd dien tich be mat rieng, dudng kinh mao qudn Idn, do trat tu cao. Chung cho phep cdc phdn tir Idn cd the de ddng khuech tdn vd tham gia phdn irng ben trong mao qudn. Trong sd dd, SBA-15, mgt thdnh vien trong hg vat lieu SBA gan ddy da nhdn dugc su quan tdm ddc biet do cd thdnh mao qudn ddy (3 6 nm), dien tich be mat ldn, mao qudn cd cau tnic deu dan vdi kich thudc rdng (2 30 nm) vd cd do ben thuy nhiet cao ban so cdc vat lieu mao qudn trung binh khdc [2]. Vat lieu SBA-15 thudng Id cdc oxit silic cd be mat it hoat dgng. Vi the, dl boat dgng hda bl mat, tren thi gidi vd trong nude da cd mdt sd cdng trinh dua cdc kim loai vdo mang [3, 4] hay gdn cac nhom chiic nang len be mat [5, 6].
Hien nay da cd mdt sd bdi bdo cdng bd ve viec dua nhdm thiol (SH) len tren be mat SBA-15 vd sir dung chiing nhu nhung chat hap phu ion kim loai ndng [7].
Mac ddu vay, van cdn it cdng trinh nghien ciru mgt cdch he thdng ve tdng hgp SBA-15 dugc chiic nang hda nhdm thiol. Trong bdi bdo nay chung tdi trinh bdy dnh hudng cua hdm lugng chat cung cap nhdm thiol Ien hinh thdi vd tinh chat cau true cua cdc vat lieu bien tinh tdng hgp dugc.
2. THUC NGHIEM
Cho 2 gam P123 (HO(CH2CH20)2o(CH2CH(CH3)0)7o(CH2CH20)2oH)
vdo trong 62,5 gam HCI 1,9 M vd khuay tren mgt mdy khudy tir cd he thdng gia nhigt cho den trong sudt. Hdn hgp dugc gia nhiet den 40°C, sau dd vira khuay vira nho tir tir 3,84 gam tetraetoxysilan (TEOS) vdo. Hdn hgp dugc khuay d 40°C trong thdi gian 45 phut, sau dd vira khuay vira nhd tir tir 3- mercaptopropyltrimethoxysilane (MPTMS) vdo.
Hdn hgp phdn ling dugc khudy lien tuc 20 gid d 40°C, sau dd gid hda mdu trong mdt autoclave d 100°C trong 24 gid. Sdn phdm rdn dugc tdch bdi lgc, rira bdng nude cat vdi Ian, sau dd dugc tdch loai chat dinh hudng cdu true bang chiet hdi luu trong 24 gid vdi dung mdi etanol. Sdn phdm cudi ciing dugc thu hdi bang cdch lgc rdi say khd 2 gid d 100°C. D I khdo sdt dnh hudng ciia hdm lugng ciia MPTMS trong hdn hgp dau, chiing tdi da tdng hgp cdc mdu cd ti le moi cua MPTMS/TEOS khdc nhau. Vat lieu biln tinh dugc ky hieu SBA-15-SH-x, trong dd x Id ty le phdn trdm so moi cua MPTMS. 100/(MPTMS + TEOS).
Pho jihieu xa tia X (XRD) cua cdc mlu dugc do tren nhieu xa ke Brucker D8 Advance vdi dng phdt tia X ciia Cu cd budc sdng X (Cu Ka) = 1,5406 A.
Ddc trung ddng nhiet hdp phu N2 dugc thuc hien tren ASAP 2010 d 77 K. Trudc khi do, cdc mdu dugc xir ly chan khdng d 100°C trong 6 gid. Phd hdng ngo^i (IR) dugc ghi tren phd kl Thermo Nicolet 6700 trong khodng 400 din 4000 cm"' Cdc hlnh dnh kinh hien vi dien tir truyen qua (TEM) vd kinh hiln vi dien tii quet (SEM) dugc ghi tren JEOL JEM-2100F
TCHH,T. 49(2), 2011 Tran Thi Thu Phuang, et al.
vd Jeol 5410 tuong irng.
3. KET QUA VA T H A O LUAN
Nhu da trinh bay trong phdn thyc nghigm, thay ddi ti lg moi ciia MPTMS bdng cdch cd djnh lugng TEOS vd thay ddi nong dg MPTMS trong hdn hgp ddu. Cdc mdu ndy dugc ky higu Id SBA-15-SII-x, trong dd x Id ti lg phdn tram so moi ciia MPTMS. 100/(MPTMS+TEOS) vd dugc thay doi tir 5, 10, 15, 20, din 30%. Hinh 1 trinh bdy gian do nhieu xa tia X gdc thdp cua cdc mdu chirc nang boa vdi ti lg moi MPTMS/(MPTMS+TEOS) khdc nhau.
s-
2 theta (dd)
Hinh 1: Gidn do nhieu xa tia X cua SBA-15-SH-5 (a), SBA-15-SH-10 (b), SBA-15-SH-15 (c), SBA-
15-SH-20 (d), vd SBA-15-SH-30 (e)
Ket qud phan tich XRD cho thay tat cd cdc mdu SBA-15-SH-X diu cd cau triic mao qudn trung binh vdi miic dg trdt t^r khdc nhau. Mure dg tr|t t^r gidm dan khi tang ham lugng MPTMS. Cdc mdu ung vdi ty lg MPTMS trong hdn hgp dau Idn hon thi cd cudng dg pic (100) ylu vd tu hon. Dilu dd chiimg td khi ham lugng nhdm thiol tang thi mure dg trat tu cua cau true lye lang gidm. Tir gid trj 20 ciia pic (100), hdng so m^ng cua cdc sdn pham ciing dugc tinh d^ra tren cdng thirc ao = 2dioo/(3)'^ dung cho doi xiimg luc lang kilu p6mm. Cdc gid trj tinh dugc d bang 1 cho thay ao khdng tang, gidm theo quy luat md ndi chung dao dgng trong khodng 10,2 = 10,8 nm.
Dk cd thdng tin vl kich thudc vd hinh dang mao quan, ba v^t ligu tong hgp dai dign SBA-15-SH-x (x = 5, 15, 30) dugc quan sat bdng TEM. Cdc kit qud d hinh 2 cho thay tat cd cdc mdu deu cd hinh dnh TEM rd net vdi mat cdt ngang mao qudn rdt ddng diu (cdc hinh a), vd mao qudn hlnh try sap xIp song song nhau (cac hinh b). Tuy vay. neu quan sdt ky.
ddi xiing lye Idng cao ban trong cdc mdu SBA-15- SH-x vdi X = 5 vd 15, trong liic dd kem horn vdi cdc mdu cd X cao hon, x = 30. Tir cdc hinh dnh TEM nay, khodng cdch giua cdc tdm mao qudn canh nhau cung dugc tinh mgt cdch gdn dung vd bang khodng 10 nm. Khodng cdch ndy cung chinh Id hdng so mang cua cdu true. Nhu vay, ket qud TEM phii hgp tdt vdi ket qud do XRD d tren.
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Hinh 2: Anh TEM cua SBA-15-SH-5 (1), SBA-15-SH-15 (2), vd SBA-15-SH-30 (3): nhin tir tren xu6ng (a), nhin tir phia ben (b)
TCHH,T. 49(2), 2011 Tdng hap vd ddc trung vdt lieu.
ket vdi nhau. Tuy vay, neu quan sdt ky chiing ta se thdy dudng kinh sgi giam dan khi tang ti le moi MPTMS. Dudng kinh sgi cd thi dugc udc djnh bdng khodng 1,0; 0,5; vd 0,2 pm doi vdi SBA-15-SH-5, SBA-15-SH-15, vd SBA-15-SH-30, tuong irng.
Tinh chat mao qudn cua cdc vat ligu chirc ndng hda cung dugc ddc trung bdng phuang phdp hap phy vd gidi hap phy N2 d 77 K (hinh 4). Cd thi thav dudng ddng nhiet hap phy vd gidi hap phy N2 ciia tdt
cd cdc mau SBA-15-SH-x deu cd vdng tre loai IV (theo phan loai ciia lUPAC), ddc trung cho vat lieu cd cau true mao qudn trung binh [8]. Khi tang ham lugng MPTMS, hien tugng ngung ty mao qudn xdy ra d dp suat thap hon vd it ro rdng ban. Dieu ndy phu hgp vdi kit qud phan bd kich thudc mao qudn dugc tinh bdng phuang phdp B.J.H. nhu da trinh bdy trong hinh 4, dd Id kich thudc mao qudn trung binh gidm khi tang hdm lugng MPTMS.
Hinh 3: Anh SEM cua SBA-15-SH-5 (a), SBA-15-SH-15 (b), vd SBA-15-SH-30 (c) Cdc thdng sd thu dugc tir ket qud hap phy, nhu
dien tich be mat, dud-ng kinh mao qudn trung binh cua cdc mdu dugc liet ke trong bdng 1. Nhirng gid trj ndy gidm khi tdng ti lg moi MPTMS. Viec gidm cdc dai lugng ndy cd the do su chiem giir cua cdc nhdm propylthiol len tren cdu true mao qudn. Bdng 1 cdn chi ra thdng sd mang ao dugc tinh todn tur ket qud XRD vd do ddy tudng mao qudn. Do ddy tudng ndy chinh Id hieu ciia a<, vdi dudng kinh mao qudn cd dugc tir ket qud hdp phu. Nhu da dugc chi ra, trong
khi gid trj ao dao ddng trong khoang 10,2 - 10,8 nm, do ddy tudng tang theo ti le moi cua MPTMS. Do ddy tudng tdng cd the Id ket qud ciia nhdm propylthiol gdn tren be mat mao qudn. Ndi tdm lai, ket qud hap phu thu dugc hodn todn phii hgp tdt vdi ket qud XRD vd ciing minh chiing su tdn tai ciia nhdm chiic ndng tren be mat mao qudn.
De minh chung them cho su cd mat ciia nhdm thiol, cdc sdn phdm tdng hgp cung dugc ddc trung hdng ngoai vd cdc ket qud dugc Uinh bdy trong hinh 5.
1000-
800
E
> 600
J:
Q.
o.
J C CS
s.
- J
400
200
9 Hap phy O Giai hip ptiu
0.0 0.2 0.4
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0 JZ
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1
1
t " •• • • •
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^ Jk " ••
1 ' 1 ' 1 ' 1 I
a
b c
e
5 10 15 20 25 Dipdng k[nh mao quan (nm)
3 0
Hinh 4: Dudng ddrig nhiet hap phy-gidi hdp phy N2 d 77 K vd Phdn bo dudng kinh mao qudn ciia SBA-15-SH-5 (a), SBA-15-SH-10 (b), SBA-15-SH-15 (c), SBA-15-SH-20 (d), vd SBA-15-SH-30 (e)
TCHH,T. 49(2), 2011 Tran Thi Thu Phuc '.. et al.
Bdng 1: Ddc trung cau true cua cdc vat ligu tong hgp Mdu
SBA-15 SBA-15-SH-5 SBA-15-SH-10 SBA-15-SI1-15 SBA-15-SH-20 SBA-15-SI1-30
SBET, m /g
800,3 720,7 690,2 582,3 430,1 210,2
Dudng kinh mao qudn, nm
6,6 6,1 5,9 5,0 4,8 3,9
ao, nm 10,8 10,5 10,4 10,2 10,5 10,6
Dg ddy thanh mao qudn, nm
4,2 4,4 4,5 5,2 5,7 6,7
CO 3 C
>
3
<0- Q
500 1000 1500 2000 2500 3000 3500 4000 24«g 24S0 ZSIt 2 M 0 2 i M 2«SI 71M 27S0
S6 song (cm-1)
Hmh 5: Phd IR cua SBA-15-SH-5 (a), SBA-15-SH-10 (b), SBA-15-SH-15 (c), SBA-15-SH-20 (d), vd SBA- 15-SH-30 (e) trong viing 400 - 4000 cm' (A); trong viing 2400 - 2750 cm"' (B)
Ket qud hinh 5A cho thdy cdc phd hong ngoai deu xuat hien cdc pic tuong ung vdi dao dgng keo cdng vd udn cong ciia lien kit C-H d vimg 2850 3000, vd 1460 cm'', rieng biet; pic ddc trung cho dao ddng keo cdng ciia lien kit C-O-C trong chat djnh hudng cau true P123 d 1350 1377 cm"' [9]. Ngodi ra, cdc pho cdn chi ra mgt pic ylu xung quanh 2570 cm"' ddc trung cho dao dgng cua nhdm thiol (S-H) [7]. Hinh 5B Id hinh dnh phdng d^i cdc phd trong vung 2400 2750 cm"', cho thdy hdu nhu tat cd cdc mau deu xudt hien pic ddc trung ndy. Tuy vay, cudng dg tang dan vd rd rdng ban khi tang ham lugng MPTMS trong hdn hgp dau. Dilu ndy hodn todn phii hgp vdi cdc kit qud XRD vd hap phy d tren rdng hdm lugng nhdm S-H trong sdn phdm tang theo ti le moi cua MPTMS trong hdn hgp phdn iirng.
4. KET LUAN
Chung tdi da tdng hgp thdnh cdng cdc vat lieu SBA-15 cd cdc nhdm thiol gdn tren bl mat. Hdm lugng nhdm thiol tang theo ti le moi MPTMS trong
mao qudn gidm; nhung dg ddy tudng mao qudn tdng.
Cdc vat lieu chirc ndng hda tdng hgp dugc cd dang hinh sgi vd kich thudc sgi gidm khi tdng ti le moi MPTMS trong hdn hgp ddu.
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Lien he: V6 Vien
Khoa Hda hgc, Dai hgc Quy Nhon
170 An Duong Vuang, Thdnh phd Quy Nhon Email: [email protected]