AN MD STUDY ON THE CORRELATION BETWEEN TRANSPORT DIFFUSION AND SELF-DIFFUSION IN ZEOLITES

Non-equilibrium Molecular Dynamics (MD) simulations in a model zeolite of structure type LTA for permeation studies following the Wicke-Kallenbach method are performed. The transport diffusivities are found to increase with increasing concentration. The concentration dependence is satisfactorily represented by the thermodynamic factor dlnp/mnc. For small concentrations, the transport diffusivities approach the self-diffusivities determined by MD simulations under equilibrium conditions. Molecular transportation in the direction perpendicular to the concentration gradient is unaffected by the non-equilibrium conditions.