Theoretical Study of CO₂/N₂ Gas Mixture Separation through a High-Silica PWN-type Zeolite Membrane

Abstract

PWN is classified as a member of the second generation of the RHO zeolite family, which is extended by embedding isoreticular structures. Here, we report the performance of a pure silica PWN-type (Si-PWN) zeolite membrane for separation of nitrogen (N 2 ) and carbon dioxide (CO 2 ) gas molecules using molecular dynamics simulations. The simulations were performed at different temperatures and applied pressure up to 10 MPa. It is found that the N 2 molecules can easily penetrate through Si-PWN, whereas no CO 2 molecule passage was seen owing to the strong van der Waals (vdW) interactions between CO 2 molecules and the Si-PWN membrane. Hence, the results suggested that Si-PWN has a very high selectivity of N 2 over CO 2 . Furthermore, the best N 2 permeance of 7.24 × 10 5 GPU across the membrane was obtained at 348 K and 0.25 MPa, which indicates the remarkable performance of Si-PWN in N 2 /CO 2 separation.

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