AbstractThe modified Enskog theory of van Beijeren and Ernst for dense fluid mixtures of rigid spheres is applied to diffusion of inert, nonadsorbing gases in microporous “leaky” membranes. Utilizing the concept of a dense dusty gas, the resulting expressions for the permeability and flux ratio illustrate the influence of steric hindrance on the transport process. The results obtained serve as corrections to the original dusty gas model of Mason and oth