Kinetic adsorption modeling of ethanol molecules onto three types of activated carbons: Microscopic interpretation of adsorption and diffusion parameters

A modeling study has been effectuated on the adsorption kinetics of ethanol onto parent Maxsorb III and the two chemically modified activated carbons (H-2-Maxsorb III and KOH-H-2-Maxsorb III). In this work, a mathematical model of diffusion-adsorption is used to describe a nonlinear sorption equilibrium coupled with the diffusion of adsorbate in porous media. The new model equation is deduced from kinetic Boltzmann equation by using a term of diffusion and a term of trapping or adsorption of ethanol at the surface of activated carbon. The term of trapping is expressed by means of Henry model of adsorption, which is in turn deduced from the Hill model developed by using statistics physics treatment. In this study, we propose a new simulation model of a gas kinetic adsorption in a microporous solid in order to find a better correlation with the experimental data. Then, we determine the effect of diffusion term and source term or more exactly trapping term, which is depending on the physicochemical parameters like the number n of molecules per site, the density of receptor sites N-m per unit mass, the half-saturation concentration N-1/2, and the residence time tau(nu), on the dynamic development of ethanol adsorption on the three types of activated carbon. (C) 2017 Elsevier B.V. All rights reserved.