Effect of micropore size distribution induced heterogeneity on binary adsorption kinetics of hydrocarbons in activated carbon

Experimental data of sorption kinetics of ethane and propane and their bina ry mixtures on Norit activated carbon under various conditions were measure d using a differential adsorber bed (DAB) rig and used to further validate the predictive capability of the kinetic model proposed by Hu, Qiao and Do (1999, Langmuir). The model utilizes the concept of micropore size distribu tion and Lennard-Jones potential theory to describe the adsorption energeti c heterogeneity on activated carbon. The pore size distribution is treated as the intrinsic property of adsorbent and taken as the sole source of soli d surface heterogeneity. A gamma distribution is used to describe the micro pore size distribution. The size exclusion effect is taken into account in the competition of different species for a given pore. The effect of the mi nimum size of pore accessible to different adsorbates on kinetics predictio n is investigated. The requirement of thermodynamic consistency for adsorpt ion equilibrium model is also studied in simulating the multicomponent adso rption kinetics. (C) 2000 Elsevier Science Ltd. All rights reserved.