Tuning the microstructure of organosilica membranes with improved gas permselectivity via the co-polymerization of 1,2-bis(triethoxysilyl) ethane and 1,2-bis(triethoxysilyl)methane

1,2-bis(triethoxysilyl) ethane (BTESE)-derived membranes have proven thermal and hydrothermal stability and molecular sieving properties. However, BTESE-derived membranes still have low gas permselectivity due to their loose structure. Herein, we propose a novel strategy of co-polymerization using precursors of both BTESE and 1,2-bis(triethoxysilyl)methane (BTESM) to improve the gas permselectivity of BTESE-derived membranes. BTESM is introduced into BTESE network and the microstructure can be adjusted by different molar ratios of BTESE to BTESM. We find that, as the content of BTESM increase, H-2 permeations of BTESE-BTESM membranes remain nearly constant, while the permeations of larger gases (CO2 and N-2 etc.) exhibit a greatly decreased. The membrane with amolar ratio of BTESE:BTESM = 3:7 exhibits the highest H-2/CO2 (11.3) and H-2/N-2 (26.8) permselectivity while having a relatively high H-2 permeance (1.52 x 10(-6) mol m(2) s(-1).Pa-1). Our findings may provide novel insights into preparation of co-polymerization organosilica membranes with excellent H-2/CO2 and H-2/N-2 separation performance. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

A novel co-polymerization strategy using both BTESE and BTESM precursors was proposed to improve the gas permselectivity of BTESE-derived membranes. The membrane with a molar ratio of BTESE:BTESM = 3:7 exhibited the highest H-2/CO2 and H-2/N-2 permselectivity while maintaining relatively high H-2 permeance. This study provides insights into the preparation of co-polymerization organosilica membranes with excellent gas separation performance.