Observation of adsorption and permeation phenomena in silica membrane system through molecular dynamics simulation

Abstract

Membrane permeation is governed by complex physical phenomena such as diffusion, viscous flow, and adsorption. Among those separation mechanisms, adsorption and surface diffusion are known to be key factors when gas molecules are adsorbed on the membrane surface. In the present study, adsorption and surface diffusion phenomena are observed through molecular dynamics simulation. A simulation scheme is applied to an amorphous silica membrane. The number of adsorbed molecules is counted and a proper adsorption isotherm is identified. Gas permeation is also simulated, and results are compared with experimental data. The permeability of carbon dioxide is investigated for the pressure change. The parameters of dusty gas model are estimated using simulation results. (C) 2004 Elsevier Ltd. All rights reserved.