Understanding the Potential of Zeolite Imidazolate Framework Membranes in Gas Separations Using Atomically Detailed Calculations

Abstract

Zeolite imidazolate frameworks (ZIFs) offer considerable potential for gas separation applications due to their tunable pore sizes, large surface areas, high pore volumes, and good thermal and mechanical stabilities. Although a significant number of ZIFs has been synthesized in the powder form to date, very little is currently known about the potential performance of ZIFs for membrane-based gas separation applications. In this work, we used atomically detailed calculations to predict the performance of 15 different ZIF materials both in adsorption-based and membrane-based separations of CH 4 /H 2, CO 2 /CH 4, and CO 2 /H 2 mixtures. We predicted adsorption-based selectivity, working capacity, membrane-based selectivity, and gas permeability of ZIFs. Our results identified several ZIFs that can outperform traditional zeolite membranes and widely studied metal organic framework membranes in CH 4 /H 2, CO 2 /CH 4, and CO 2 /H 2 separation processes. Finally, the accuracy of the mixing theories estimating mixture adsorption and diffusion based on single component data was tested.