Functionalized α-GDY with different displacement distance for CO2/CH4 diffusion and separation

Abstract

Functionalized α-GDY with – H, – F, and – N for different displacement distance were designed as promising membranes for separation CO2 from CH4 by using molecular dynamics simulations. The α-GDY were regulated to form suitable pore sizes by functionalization and displacement for separation CO2 from CH4. F-GDY membranes and displacement distance with 1/3 have ultralow CO2 selectivity over N2 of ~0, which indicate that no CO2 pass through F-GDY membranes and CO2 and CH4 were separated efficiently. Among these membranes, N-GDY with 1/3 displacement distance has highest permeance of 5.97 × 10-5 mol m-2 s-1 Pa-1 at 300 K. Relative concentrations distribution confirmed that almost CO2 molecules adsorbed the pore wall of membrane, CH4 distributed in the gas box and vacuum. The interaction energy between gas molecules and membrane was analyzed to elucidate the significant impact of functionalization on the selectivity of CO2 over CH4 and CH4 permeances passing through porous BN membranes.