Grain Boundary Modelling of Zeolite Membranes for Higher CO₂ Selectivity

Abstract

Non-equilibrium molecular dynamics was performed to investigate the influence of the grain boundary region in CHA-type zeolite membranes on the permeability and selectivity of a CO₂/CH₄ gas mixture. It was confirmed that under the investigated gas pressure, the grain boundary was preferentially occupied by CO₂, resulting in an increase in the CO₂ selectivity and flux. The results indicated that a CHA membrane with a fine controlled grain boundary structure could exhibit increased selectivity and permeability for condensable gas species compared to perfect crystalline CHA membranes.