Sorption Kinetics and Equilibria on 4A Molecular Sieves

Abstract

<p>Adsorption rates and equilibria of several gases on 4A zeolite powder were measured with the aid of a constant pressure, variable volume apparatus. Data are presented for Ar, CH₄, N₂, C₂H₆, CO, CO₂ and O₂ at various temperatures between -150ºC and +20ºC. In calculating diffusivities, due account was taken of the fact that the zeolite particles were cubes having a range of sizes.</p> <p>Equilibrium data are represented by Martin's version of the viral equation for two - dimensional non-ideal cases.</p> <p>Diffusivities generally increase with adsorbate concentration and this tendency is more marked for gases which can strongly interact with the sodium cations in the 4A zeolite crystal structures. Entropies and enthalpies of activation for diffusion are presented and explained in terms of the molecular properties and heats of adsorption for the various adsorbates.</p>