Molecular Dynamics Simulation on Diffusion Properties of Simple Gases in Zeolite ITQ-3

The equilibrium molecular dynamics simulation was conducted to study the diffusion of Ne,CH4 and Ar in the two-dimensional zeolite ITQ-3,and the dependence of diffusion coefficients on adsorptions in two directions was explored.As the loading increasing,the diffusion coefficients increase to its maximum point and decrease afterwards along the narrow pore in Z direction.The diffusion coefficients along Y direction with relatively wider pores,however,decrease monotonically with respect to its loading.The two distinct diffusion mechanisms can be clearly explained by the calculation of potential energy profiles.The reduction of diffusion activation energy makes the diffusion coefficient an increasing function with respect to the loading.The simulations showed that,even for the zeolites with the same kind of cavities,the diffusion exhibited different relations with respect to the loadings according to different pores and different molecular size.