抄録
Understanding the permeation phenomena through molecular interactions and membrane structures is important for effective membrane design. This paper describes a brief review of a novel non-equi-librium molecular dynamics (μVT-NEMD) technique, which we have recently applied for simulating gas permeation, and some results calculated for permeation of single and mixed gases through carbon membranes with slit-shaped pores. One important observation obtained from simulations may be an image of surface flow for permeating gases. It is also noted that permselectivity of mixed gases has been controlled by the competitive adsorption equilibrium at the feed side of membrane when calculations were performed under the assumption of local adsorption equilibrium between the feed gas and the entrance part of a pore. A small heterogeneity on pore surfaces is found to result in large decrease in the permeation fluxes. Simulations on gas permeation at the feed side provide a view that molecules enter into the slit-pore either directly into the pore mouth or indirectly through the outer surface of the pore after they are adsorbed. Frequent moves of molecules onto the outer surface from the pore inside are also observed when molecules leave the pore to the gas phase.
