Diffusion of binary mixtures in zeolites: molecular dynamics simulations versus Maxwell–Stefan theory

The Maxwell–Stefan formulation of diffusion in multicomponent mixtures is used to obtain explicit formulae for calculating the diffusivities of binary mixtures within a zeolite matrix. The theoretical development allows the estimation of the mixture diffusivities on the basis of the pure component diffusivities at zero loadings. The applicability of the Maxwell–Stefan model is demonstrated by comparison with published molecular dynamics simulations for mixtures of methane–perfluoromethane, methane–xenon, and methane–n-butane in silicalite.