Molecular sieve carbons. Part 3.—Adsorption kinetics according to a surface-barrier model

Abstract

The kinetics of the adsorption of gases on molecular sieve solids can be rate-determined by a surface barrier constituted of a thin layer of adsorbate at high coverage. The layer is not necessarily associated with the morphology of the adsorbent.

The surface-barrier mechanism applies in cases of a sharp pressure increment which corresponds to a high degree of saturation. In the other cases, a bulk diffusion or mixed surface-barrier and bulk-diffusion mechanisms would prevail.

The applicability and the importance of the surface-barrier mechanism are discussed.