Kinetics of adsorption and diffusional characteristics of carbon molecular sieves Original Research Article

Commercially available carbon molecular sieve (CMS) materials, from a variety of sources, and molecular sieving carbons produced from the carbonization of coal have been studied. These materials have been assessed in terms of their kinetics of adsorption of oxygen and nitrogen. The diffusion kinetics of gases into the carbons have been analysed using Fickian and phenomenological models. The Arrhenius activation energies and pre-exponential factors for gas adsorption in the two types of material have been compared. The adsorption kinetic results are discussed in relation to structural models for carbon molecular sieves where the kinetic selectivity for gases has been introduced by carbon deposition in the case of commercial CMS and by the variation of carbonization conditions in the case of the coal-based carbons produced in the laboratory.