The generalized Maxwell–Stefan model for diffusion in zeolites:: sorbate molecules with different saturation loadings

Abstract

Using the Maxwell–Stefan approach, expressions have been derived for the diffusion of mixtures of hydrocarbons in zeolites wherein the individual components have different saturation loadings. This Maxwell–Stefan diffusion model, in combination with the Ideal Adsorbed Solution (IAS) theory and the single-component adsorption isotherms, provides a superior, qualitative and quantitative, prediction of the permeation fluxes of ethane/methane and propane/methane mixtures through a silicalite-1 membrane. The difference in adsorption saturation loadings becomes apparent in the entropy effects in the mixture adsorption.