多孔石墨烯气体分离膜分子渗透机理

摘要

A molecular dynamics simulation was performed to probe the mechanism of molecular permeation through nanoporous graphene gas separation membranes. The investigation involves 4 different gas molecules (He, H2, N2 and CH4) permeating 9 graphene nanopores with different sizes. The results show that the permeation flux depends not only on the kinetic parameters of molecules, i.e. molecular mass and kinetic diameter, but also on the adsorption of molecules on the surface of graphene membrane. Apart from the permeation free of interactions with the graphene surface, the adsorption layer composed of molecules with high densities on the graphene surface provides an additional way for molecular permeation, increasing the permeation flux as the molecular adsorption increases. In addition, the permeation flux of H2 molecules increases linearly with the pressure for different graphene nanopores.%通过分子动力学方法模拟了4种不同气体分子（He，H2，N2和CH4）在多孔石墨烯气体分离膜中的穿透过程，揭示了气体分子穿透石墨烯纳米孔的渗透机理，指出分子的渗透不仅与其动力学参数有关，如分子直径和质量，还与分子在石墨烯表面的吸附有关。石墨烯表面的吸附层给气体分子的渗透提供了一个额外的路径，因此分子在石墨烯表面的吸附越强，分子的渗透通量越大。同时，不同大小的纳米孔下H2分子的渗透通量都随着压力的增加而线性增加。