The removal of nitrogen monoxide from polluted air using CHA- and DDR-type zeolite membranes: Insights from molecular simulations

The abatement of nitrogen monoxide (NO) from the polluted air is a very significant challenge in the industries. In the present work, molecular simulation was carried out to study the ability of pure silica CHA- and DDR-type zeolite membranes for separation of NO molecules from a gas mixture including NO/N2/O2 under temperature ranges (298, 323, and 348 K) and applied pressures up to 1000 kPa. The simulation results showed the N2 and O2 molecules transferring through Si-CHA and Si-DDR membranes, while NO molecules could not pass through them. In this regard, high removal of NO molecules from NO/N2/O2 gas mixture through the studied membranes was obtained, which makes them promising for separation of NO molecules from polluted air at industrial relevant compositions. Besides, the potential of mean force (PMF) profile was calculated for gas molecules along the z-direction through the studied membrane, which confirmed the simulation results for molecules permeation. The PMF indicated that the NO molecules face the highest energy level difference as an energy barrier, and cannot pass through the membranes under studied conditions. It is hoped that this research will be helpful for the design and development of membranes in order to remove contaminants from gas mixtures. The illustration of the simulated system along the z-axis containing (a) Si-CHA membrane and (c) Si-DDR membrane, in the center of the simulation box; NO/N2/O2 gas mixture in the feed section; and stable graphene nanosheet at the ending of feed section (cyan, blue, green, and red colors are graphene, oxygen, nitrogen, and silicon, respectively, and (b) The nanoporous Si-CHA membrane, and (d) The nanoporous Si-DDR membrane from the xy-surface viewpoint. [Display omitted] •Separation of NO/N2/O2 mixture through CHA & DDR zeolite membranes.•Investigating the effect of temperature rise on the separation of NO/N2/O2 mixture.•Investigation of applied pressure on the separation of NO/N2/O2 mixture.•Comparison of CHA & DDR zeolite membranes in NO removal from NO/N2/O2 mixture.