Predicting gas separation performances of porous coordination networks using atomistic simulations

Abstract

Porous coordination networks (PCNs) 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 large number of PCNs have been synthesized to date, the potential performance of PCNs for adsorption-based and/or membrane-based gas separation applications is not known. In this work, we used atomically detailed simulations to predict the performance of PCN materials both in adsorption-based and in membrane-based separations of CH4/H-2, CO2/CH4, CO2/H-2, and CO2/N-2 mixtures. After validating the accuracy of our atomic simulations by comparing simulated adsorption isotherms of CO2, CH4, H-2, and N-2 with the available experimental data, we predicted adsorption-based selectivity, working capacity, regenerability, sorbent selection parameter, diffusion-based selectivity, membrane-based selectivity, and gas permeability of various PCNs. Several PCNs were predicted to outperform traditional zeolites and widely studied metal organic frameworks in CO2 separation processes. PCN-26 was identified as a potential membrane material that can exceed the upper bound established for CO2/CH4 and CO2/N-2 separations due to its high CO2 permeability and selectivity.