Highly Oriented DDR Zeolite Membrane for Effective Separation of CO2

Abstract

In this study, highly oriented all-silica-deca-dodecasil 3R zeolite membrane (i.e. (101)-oriented DDR membrane) was employed to effectively separate CO2 from N2, which is critical in the post-combustion carbon capture process. The presence of water enhanced the separation performance of DDR zeolite, and this water effect was verified via molecular simulation methods. Density Functional Theory (DFT) calculation has compared the relative preference of the adsorption of gas molecules on zeolite membrane, and CO2 molecule was less disfavored by water molecules on the surface. This energy stabilization effect of CO2 adsorption was more pronounced when a water molecule was a little closer to the pore window. Grand Canonical Monte Carlo (GCMC) with slab model represented the dominant surface wetting by water molecules. These results suggest that the overall transport of N2 was restraint by adsorbed water molecules on the membrane surface.