CVD法制备Sn掺杂MFI分子筛膜及其对乙醇/水体系的分离性能

Sn-modified MFI zeolite membranes were prepared by chemical vapor deposition(CVD) method using anhydrous SnCl₄ as Sn source, and were applied for the separation of alcohol-water mixture by pervaporation. SEM, XRD, ²⁹Si NMR and UV-Vis analyses showed that Sn can be introduced into the framework of MFI zeolite membranes by CVD process with their structure remained. The surface Si-OH groups can be effectively reduced after the incorporation of Sn, and the obtained membranes showed improved stability. The zeolite membrane prepared with 3 mL of SnCl₄ at autoclave bottom and the reaction time of 1 h had the best separation performance and also showed a long-term stability for the separation of 5% ethanol/water mixture at 60 ℃. After 50 h, the permeation flux slightly decreased from 1.52 kg•m^-2•h^-1 to 1.38 kg•m^-2•h^-1, and the separation factor decreased from 18 to 16.