多孔陶瓷管基膜上合成ZSM-5沸石膜新方法

A novel method for preparation of ZSM-5 zeolite membrane on porous α-Al_2O_3 tubes

采用喷涂晶种法在多孔α -Al2 O3基膜上引入一晶种层后 ,再用水热法一次可合成出渗透量大、选择性高的 ZSM-5沸石膜 .XRD、SEM及气体渗透性对所合成膜的结构、形态和分离性能表征表明 :所合成的膜是典型的 ZSM-5沸石膜 ,膜表面晶粒排列有序 ,整齐地连成一致密层 ,未发现有裂缝、针孔等缺陷 .H2 的渗透率很大 ,在常温下可达 2 .70× 1 0 - 6 mol.m- 2 .Pa- 1 .s- 1 ,H2 /C3H8的分离因数达 1

ZSM-5 zeolite membranes were prepared by in situ hydrothermal synthesis on porous α Al 2O 3 tubes coated with ZSM 5 seeds using a novel method. A colloidal ZSM 5 suspension was prepared by dispersing the ZSM 5 particle (seed) in silica sol at w =0.8%~1.0%. The support tubes were seeded by spraying seed coating with the particle suspension. During the following hydrothermal treatment, ZSM 5 particles act as seed crystals and the seed coating acts as a transitional layer. Thus continuous films are formed, which are characterized by XRD, SEM and single gas permeances. It is shown that these membranes are really defect free ZSM 5 membranes. The permeance for H 2 is 2.70×10 -6 mol·m 2 ·Pa 1 ·s 1 , separation factor for H 2/C 3H 8 is as high as above 14. This synthesis method is beneficial to the formation of zeolite membrane.