Use IAST with MPSD to predict binary adsorption kinetics on activated carbon

A model using the ideal adsorbed solution theory (IAST) coupled with the mi cropore-size distribution (MPSD) concept is proposed to describe the multic omponent adsorption equilibrium and kinetics of gases in activated carbon. To overcome the thermodynamic violation, the IAST instead of the extended L angmuir equation was used to calculate the local multicomponent adsorption equilibrium. The micropore size is related to the adsorbate-adsorbent inter action energy by the Lennard-Jones potential. The overall adsorption isothe rm and the diffusion flux of the adsorbed species are the integrals of thei r corresponding local values over all micropore-size distribution range acc essible by the adsorbate molecules. The size exclusion effect was taken int o account in the competition of different sized molecules for a given pore. The model predictions were tested with the adsorption kinetics data of bin ary gases on Ajax and Norit activated carbon. The results were better than predictions of a previous multicomponent adsorption kinetics model also usi ng the MPSD concept, but with the local multicomponent adsorption isotherm described by the extended Langmuir equation.