The cooperative effect of the surface heterogeneity and of the lateral interactions between adsorbed molecules on adsorption of simple aromatic compounds from dilute aqueous solutions on activated carbons

The cooperative effect of the surface heterogeneity and of the interactions between adsorbed molecules on adsorption of simple aromatic compounds from aqueous solutions is presented. The phenomenon is investigated on the basis of adsorption isotherms of phenol and aniline from dilute aqueous solutions at various pH values on activated carbons prepared from different precursors. The literature experimental data concerning phenol adsorption from aqueous solutions on APET carbon prepared from polyethyleneterephthalate (PET) as well as the data of aniline adsorption on commercial ACP carbon prepared from peat have been utilized.The lateral interactions in the adsorbed phase are taken into account by use of the Fowler–Guggenheim (FG) isotherm, and by use of isotherms based on vacancy solution model (VSM) in conjunction with the Flory–Huggins (FH) and Wilson (W) activity coefficient equations. By assuming the definite form of the local isotherm of adsorption in the integral equation (IE) and quasi-Gaussian distribution of adsorption energy, the condensation approximation (CA) approach led to new isotherm equations for single-solute adsorption from dilute solutions.