Non-equilibrium MD studies on gas permeation through carbon membranes withbelt-like heterogeneous surfaces

The mu VT-NEMD method, a combination of the mu VT-MC and the boundary-drive n NEMD, is used for simulating permeation of pure and mixed gases through s lit-shaped carbon membranes with belt-like heterogeneous surfaces under the assumption of local adsorption equilibrium at the membrane entrance. The b elt-like heterogeneous surfaces are made by removing carbon atoms of the fi rst layer in a lint vertically to the permeate direction. Methane and ethan e are used as permeating gases. The values of permeation resistance increas e almost exponentially with an increase in the potential barrier; the resis tance for ethane is always larger than that for methane. In the case of a b inary system, the permselectivity is determined by the adsorption equilibri um at the feed side when the potential barrier is low, while it sharply dec reases with increasing potential barrier. This result suggests that the sep aration mechanism changes from the adsorption equilibrium control to the pe rmeation rate control in the pore. The curve of the molar flux of ethane ag ainst temperature has a minimum point where temperature is about 510 K.