Sorption Equilibria and Kinetics of Sequential Sorption in Zeolite Molecular Sieves

Abstract

<p>The counter-diffusion of a series of low moIecuIar weight, permanent gas sorbate pairs on synthetic zeolites of various pore-geometries and dimension, was investigated in a semi-automatic flow system. Results of the binary diffusion studies were compared to the single component kinetics of the same species to determine the effect of the adsorbate/desorbate interactions as well as the relationship between the zeolitic pore dimension and molecular size and the respective contributions to the binary diffusion rates.</p> <p>Equilibrium studies of the individual sorbate molecules were carried out in a conventional BET volumetric apparatus. The experimental isotherms were correlated to a two-dimensional analog of a three-dimensional virial equation with good results.</p> <p>Existing diffusion models applicable to the binary sorption system were investigated. Also, a novel kinetic model for diffusion in zeolites based on the principle of random walk has been developed. Qualitatively, the model produces many of the pertinent features observed in the experimental studies.</p>