In this study, the permeation phenomena of helium, nitrogen, and carbon dioxide gases are observed through dual control volume grand canonical molecular dynamics method, which is a combination of molecular dynamics simulation and grand canonical Monte Carlo method. Adsorption isotherm and angle distribution inside pores are analyzed to identify the permeation characteristics. Also, permeability and separation factor of pure gases and mixtures are investigated for the change of pressure, temperature, and composition. The predicted properties are compared with experimental data. The separation mechanisms of pure and mixture systems are identified through the analyses of simulation results. (c) 2006 Elsevier Ltd. All rights reserved.