The transport diffusion of hydrogen and hydrocarbons (methane, ethane, propane, and n-butane) in nanoporous carbon membranes with slit-like pores was calculated using a dynamic Monte Carlo simulation method. Molecular movements were characterized by surface diffusion in which fluxes were strong close to the location of the pore wall. The pore size was an important factor in determining the selectivity of hydrocarbons in the membranes. Relative diffusivities were affected by the pore width, especially in the case of methane and ethane in small pores. The pore width played a significant role in determining the separation efficiency of carbon membranes. In the case of methane, the diffusion coefficient decreased as the pore width increased because the cross-sectional area increased and no more molecules were absorbed. In the case of propane, some molecules formed second layers due to strong adsorption of propane on graphite.

Monte Carlo Simulation of Transport Diffusion in Nanoporous Carbon Membranes. Y.G.Seo: Journal of Membrane Science, 2002, 195[1], 65-73. See also: Journal of Membrane Science, 2001, 195[1], 65-73