The correlation between structural characteristics of activated carbons and their adsorption of organic solutes from aqueous solutions

Abstract

Adsorption is controlled by an array of attractive forces between adsorbent, adsorbate, and solvent molecules. Such forces work interactively, making the interpretation and prediction of sorption processes difficult. By carefully designing the experimental matrix, the effects of adsorbent surface chemistry and pore structure on the adsorption of aromatic compounds were isolated from the complicated web of interactions. Two parameters, γ and δ, were created to describe the relative adsorption affinity index of activated carbons to adsorbates and the occupancy rate of activated carbons by active sites that can lead to formation of water clusters. Taking the space availability and the relative adsorption affinity index into account, a correlation between the Freundlich adsorption affinity coefficient and the characteristics of adsorbent was established. With this correlation, if the Freundlich adsorption affinity coefficient of a compound on one carbon is known, its adsorption affinity coefficient on another carbon might be predictable if the surface chemistries and pore structures of both carbons are available.