Intracrystalline diffusion of benzene in NaX zeolite studied by sorption kinetics

Abstract

Sorption uptake measurements have been used to measure the intracrystalline diffusivities of benzene in NaX zeolite within wide ranges of sorbate concentration at different temperatures. Their success is due to a significant decrease in the response time of the uptake equipment (< ca. 0.1 s) compared with current methods, this being obtained by application of a recently developed method of data evaluation that accounts for external effects (via a theory of statistical moments) and by using relatively large zeolite crystals (ca. 120 µm). The coincidence of corrected sorption diffusion data with n.m.r. self-diffusivities indicates that the sorption technique gives reliable information on intracrystalline molecular mobility, even for hydro-carbons in large-port microporous sorbents.