EFFECT OF SURFACE ENERGETIC HETEROGENEITY ON THE KINETICS OF ADSORPTION OF GASES IN MICROPOROUS ACTIVATED CARBON

A model allowing for surface energetic heterogeneity is presented to describe the adsorption and desorption kinetics of gaseous adsorbates in large microporous particles. The effects of surface energetic heterogeneity on both sorption kinetics and equilibrium (rather than on equilibrium only) are studied. Parameters extracted from single component fittings are used to predict the multicomponent sorption dynamics. Single and multicomponent experimental data of sorption dynamics of ethane and propane in Ajax activated carbon, which are obtained by using a differential adsorption bed, are used to demonstrate the potential of the proposed model. It is found that the role of energetic heterogeneity is not important in the model fittings of adsorption kinetics of single component, but it plays a vital role in the predictions of desorption kinetics of single species and adsorption and desorption processes of multicomponent gases in microporous particles. This finding has a far reaching consequence as all adsorption systems of industrial interest involve interaction of many adsorbates.