利用ＴＧ－ＤＴＡ、ＢＥＴ法分析研究了热处理过程的膜孔径分布、孔径大小及膜的比表面积、比孔容随焙烧温度的变化趋势，并用ＸＲＤ研究了氧化铝膜的膜内晶体的晶面取向，用ＴＥＭ、ＳＥＭ观察用溶胶─凝胶法制备的氧化铝膜的表面及截面形貌．发现构成氧化铝膜的微晶的择优取向度决定着膜孔径分布的均匀性，焙烧温度越高，膜微晶的择优取向度越大，膜的孔径分布越窄，但孔径增大．膜的比表面积、比孔容在４００℃有一最大值，４００℃是合适的膜催化、反应用膜的焙烧温度，这时膜比表面积、比孔容和孔隙率分别为２８３ｍ２／ｇ、０．３３８ｍＬ／ｇ和５３％．７００℃是分离用膜的合适焙烧温度，这时膜比表面积、比孔容和孔隙率分别为２０２ｍ２／ｇ、０．２０３ｍＬ／ｇ和４５％．７００℃时膜的最大孔径为５ｎｍ；孔径为１～１．２５ｎｍ的孔占孔体积的７０％以上．
The physical and chemical characteristics, pore radius, pore size distribution and surface area, pore volume, porosity of the the membrane prepared
by sol-gel method using aluminum isoproxide were studied using TG--DTA, BET at different firing temperature from room temperature to 1000℃. The
preferred orientation of alumina micrograin of the alumina membrane was studied by XRD. The surface and cross-section were observed by TEM and SEM.
The pore size distribution are influenced by preferred orientation of alumina micrograin. The higher the firing temperature, the higher the degree of the
preferred orientation, the more the uniformity of the pore size distribution of the membrane, the bigger the largest the pore radius of the membrane.
400℃ is suitable firing temperature of the membrane used as membrane catalysis and/or membrane reaction with the largest the surface area, pore volume and porosity of 283m2/g, 0.338mL/g and 53%. 700℃ is
suitable firing temperature of the membrane used as separation with the surface area, pore volume and porosity of 202m2/g, 0.203mL/g and 45%.
The largest pore radiu is 5nm, pore with radius of 1～1.25nm is above 70% pore volume at 700℃.
参考文献
| [1] | Samio Sakka, Hiromitsu Kozuka, Tatsuhiko Adachi. Preparation of Porous Materials by the Sol-Gel Method, In: Porous Materials, Kozo Ishizaki, Shojiro Okada, Hamasaki, et al ed. The American Ceramic Society, 1993. 27 2 Larbot A, Fabre J P, Guizard C, it et al. J. Membrane Science, 1988, 39: 203--212 3 LIN Y S, de Vries K J，Burggraaf A J. J. Mater. Science, 1991, 26: 715--720 4 Leenaars A F M, Keizer K, Burggraaf A J. Journal of Materials Science, 1984, 19: 1077--1088 5 Huang Xiao-rong, Huang Zhongtao. J. Membrane Science, 1997, 133: 145--150 6 黄肖容，黄仲涛. 硅酸盐学报, 1997, 25 (1): 110--114 |
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