In this work we simulate the permeation of Lennard-Jones gases across
a zeolite model membrane. Using a newly developed dual control volume
grand canonical molecular dynamics technique, we create spatial variat
ion in the chemical potential in a dynamical system and hence an accur
ate simulation of steady-state pressure-driven diffusion. The molecula
r sieving nature of microporous zeolites is discussed, and the results
from the simulation are compared very favourably with recent experime
ntal results of He, H-2 and CH4 permeation through ZSM-5 polycrystalli
ne membranes. A massively parallel algorithm is utilized to give a qui
ck and insightful study of this and other microporous materials for us
e as membranes.