the generalized maxwell-stefan model coupled with vacancy solution theory of adsorption for diffusion in zeolites

it seems using the maxwell-stefan (m-s) diffusion model in combination with the vacancy solutiontheory (vst) and the single-component adsorption data provides a superior, qualitative, andquantitative prediction of diffusion in zeolites. in the m-s formulation, thermodynamic factor (г) isan essential parameter which must be estimated by an adsorption isotherm. researchers usually utilizethe simplest form of adsorption isotherms such as langmuir or improved dual-site langmuir, whicheventually cannot predict the real behavior of mixture diffusion particularly at high concentrations ofadsorbates because of ignoring nonideality in the adsorbed phase. an isotherm model with regard tothe real behavior of the adsorbed phase, which is based on the vacancy solution theory (vst) andconsiders adsorbate-adsorbent interactions, is employed. the objective of this study is applyingvacancy solution theory to pure component data, calculating thermodynamic factor (г), and finallyevaluating the simulation results by comparison with literature. vacancy solution theory obviouslypredicts thermodynamic factor better than simple models such as dual-site langmuir.