Application of IAST in the prediction of multicomponent adsorption equilibrium of gases in heterogeneous solids: Micropore size distribution versus energy distribution

This article investigates the effect of surface heterogeneity and energy-ma tching scheme on the prediction of adsorption equilibria on activated carbo n. The ideal adsorbed solution theory (IAST) is employed to evaluate the lo cal adsorption equilibria on each energy site while the energetic heterogen eity of the system is represented by two forms: (1) uniform energy distribu tion, which employs the cumulative energy scheme to match different adsorba tes in the adsorbed phase; and (2) micropore size distribution, which invok es the adsorbate-pore interaction matching scheme. The adsorption equilibri a of hydrocarbon gas mixtures measured on two commercial activated carbons are used to compare the two models. It is found that uniform energy distrib ution can be insufficient in the prediction of multicomponent adsorption eq uilibria. On the other hand, the model assuming micropore size distribution as adsorption energetic heterogeneity and the adsorbate-pore interaction e nergy-matching scheme presents relatively stable prediction results.