MFI型分子筛膜的制备及气体渗透特性  

Preparation and Gas Permeation Characteristic of MFI Type Zeolite Membrane

作　　者：袁文辉[1] 胡小芳[1] 

机构地区：[1]华南理工大学化工与能源学院广东省绿色化学品重点实验室,广东广州510640

出　　处：《材料科学与工程学报》2006年第1期44-48,共5页Journal of Materials Science and Engineering

基　　金：教育部留学基金;教育部传热与节能重点实验室资助项目;广东省自然科学基金资助项目(04020126)

摘　　要：采用原位水热合成和无模板剂二次生长合成的方法,在-αAl2O3基膜上合成了MFI型分子筛膜,用XRD,SEM和气体渗透实验等方法进行表征,表明合成在-αAl2O3基膜的物质为MFI型分子筛。原位合成的分子筛膜,氢/异丁烷的理想分离系数在298K和473K时分别为97和52;二次生长合成的分子筛膜,氢/异丁烷的理想分离系数在298K和473K时分别为497和370,远大于它们Knudsen扩散5.34的比值,表明气体是通过MFI型分子筛的孔道透过。SF6分子动力学直径大于分子筛膜孔径,H2/SF6分离因子远大于Knudsen扩散值,几乎不透过分子筛膜。原位合成分子筛膜的正/异丁烷理想分离系数在298K和473K时分别为24和17;二次生长分子筛膜的正/异丁烷理想分离系数在298K和473K时分别为77和74。气体渗透分离实验结果表明,两种分子筛膜对气体分离是由分子筛分占主导,分子筛膜完整没有缺陷。MFI type zeolite membranes have been prepared on α-Al2O3 substrate by in situ hydrothermal synthesis with template and secondary growth synthesis without template. XRD, SEM and gas permeation experiments have been applied to characterize the zeolite membranes. Ideal separation factors of H2/i-butane on MFI type zeolite membrane by in situ hydrothermal synthesis reach 97 and 52 at 298K and 473K, and those on MFI type zeolite membrane by secondary growth synthesis up to 497 and 370 respectively. Both separation factors are much more than that of Knudsen diffusion coefficient, which manifests that the gas molecule passes through the pore in zeolite membrane. SF6 can hardly permeate the both zeolite membranes because ideal factors of H2/SF6 are more than Knudsen diffusion coefficient. Ideal separation factors of n-butane/i-butane on MFI type zeolite membrane by in situ hydrothermal synthesis are up to 24 and 17, and those on MFI type zeolite membrane by secondary growth synthesis up to 77 and 74 respectively. It is shown that the gas separation is dominated by molecular sieving mechanism on both zeolite membranes that are free of defect.

关 键 词：MFI分子筛膜 二次生长法 气体渗透 分离因子 

分 类 号：O484[理学—固体物理]