This paper reports on a new microporous composite silica membrane prepared via acid-catalyzed polymeric route of sol-gel method with tetraethylorthosilicate(TEOS)and a bridged silsesquioxane[1,2-bis(triethoxysilyl)eth...This paper reports on a new microporous composite silica membrane prepared via acid-catalyzed polymeric route of sol-gel method with tetraethylorthosilicate(TEOS)and a bridged silsesquioxane[1,2-bis(triethoxysilyl)ethane, BTESE]as precursors.A stable nano-sized composite silica sol with a mean volume size of^5 nm was synthesized. A 150 nm-thick defect-free composite silica membrane was deposited on disk support consisting of macroporous α-Al2O3 and mesoporousγ-Al2O3 intermediate layer by using dip-coating approach,followed by calcination under pure nitrogen atmosphere.The composite silica membranes exhibit molecular sieve properties for small gases like H2,CO2,O2,N2,CH4 and SF6 with hydrogen permeances in the range of(1-4)×10 -7mol·m -2·s -1·Pa -1(measured at 200°C,3.0×105 Pa).With respect to the membrane calcined at 500°C,it is found that the permselectivities of H 2 (0.289 nm)with respect to N2(0.365 nm),CH4(0.384 nm)and SF6(0.55 nm)are 22.9,42 and>1000,respectively, which are all much higher than the corresponding Knudsen values(H2/N2=3.7,H2/CH4=2.8,and H2/SF6=8.5).展开更多
基金Supported by the National Natural Science Foundation of China(20906047)the State Key Laboratory of Chemical Engineering(SKL-ChE-09A01)the State Key Laboratory of Materials-Oriented Chemical Engineering(ZK201002)
文摘This paper reports on a new microporous composite silica membrane prepared via acid-catalyzed polymeric route of sol-gel method with tetraethylorthosilicate(TEOS)and a bridged silsesquioxane[1,2-bis(triethoxysilyl)ethane, BTESE]as precursors.A stable nano-sized composite silica sol with a mean volume size of^5 nm was synthesized. A 150 nm-thick defect-free composite silica membrane was deposited on disk support consisting of macroporous α-Al2O3 and mesoporousγ-Al2O3 intermediate layer by using dip-coating approach,followed by calcination under pure nitrogen atmosphere.The composite silica membranes exhibit molecular sieve properties for small gases like H2,CO2,O2,N2,CH4 and SF6 with hydrogen permeances in the range of(1-4)×10 -7mol·m -2·s -1·Pa -1(measured at 200°C,3.0×105 Pa).With respect to the membrane calcined at 500°C,it is found that the permselectivities of H 2 (0.289 nm)with respect to N2(0.365 nm),CH4(0.384 nm)and SF6(0.55 nm)are 22.9,42 and>1000,respectively, which are all much higher than the corresponding Knudsen values(H2/N2=3.7,H2/CH4=2.8,and H2/SF6=8.5).
