电泳沉积法所制γ-Al_2O_3微孔膜的结构和性能的研究

A Study of Structures and Properties of γ-Al_2O_3 Microporous Membranes Made by Electrophoretic Deposition

以制得的Al(OH)_3溶胶为电泳液,用电泳沉积法制备了平均孔径为4.6nm的γAl_2O_3微孔膜。采用SEM、孔径分布等测定方法考察了γ-Al2O_3膜的微观形貌和孔结构,并研究了其气体透过性。结构表明,γ-Al2O_3膜表面是平整的,未见明显开裂,且膜上有气孔存在。随着焙烧温度的升高,γ-Al_2O_3晶粒长大,形状变得更加规整,粒径大小均匀;孔径分布集中性降低,大孔比例、孔容及孔隙率都有显著增大,表明控制焙烧温度可调控孔大小及其分布。气体H_2/N_2和O_2/N_2可充分透过γ-Al_2O_3膜,其气体透过机理应为努森扩散为主。

γ-A12O3 microporous membranes with an average pore size of 4-6nm are obtained by elec- trophoretic deposition of A1(OH)3 sol-Even γ-Al2O3 membranes have been prepared by electrophoretic deposition.Either the peak of pore size distribution of γ-Al2O3 membranes becomes wider or the porosity and pore volume may increase with calcine temperatures.The transport mechanisms of the ges mixture H2/N2 or O2/N2 through the micro-porous γ-Al2O3 membranes combine Knudsen diffusion and laminar flow because the mean pore diameter of γ-Al2O3 membranes is 4.6nm.And Knudsen diffusion dominates the gas transport.