An equation for multi-solute adsorption from dilute aqueous solutions involving energetic heterogeneity of the solid and differences in molecular sizes of the solutes

This work presents a simple model for multi-solute adsorption from dilute aqueous solutions on solids. The proposed model leads to a simple relationship defining dependence between adsorbed amounts and concentrations of two arbitrary solutes. This relationship is derived by assuming ideality of both phases, energetic heterogeneity of the solid and different molecular sizes of solutes.The experimental data for bi-solute adsorption from dilute aqueous solutions on activated carbon, available from literature, are used to examine the proposed equation. These studies show that the new equation gives good representation of the bi-solute adsorption data.