The adsorption of pharmaceutically active compounds from aqueous solutions onto activated carbons

•Pharmaceutically active compounds are adsorbed on commercial activated carbons.•Activated carbons differ in terms of their textural and surface characteristics.•The heats of interactions were measured by means of calorimetry.•The adsorption is controlled mostly by textural characteristics of activated carbons.•Activated carbons’ acid/base features are of significance for adsorption. In this study, the adsorption of pharmaceutically active compounds – salicylic acid, acetylsalicylic acid, atenolol and diclofenac-Na onto activated carbons has been studied. Three different commercial activated carbons, possessing ∼650, 900 or 1500m2g−1 surface areas were used as solid adsorbents. These materials were fully characterized – their textural, surface features and points of zero charge have been determined. The adsorption was studied from aqueous solutions at 303K using batch adsorption experiments and titration microcalorimetry, which was employed in order to obtain the heats evolved as a result of adsorption. The maximal adsorption capacities of investigated solids for all target pharmaceuticals are in the range of 10−4molg−1. The obtained maximal retention capacities are correlated with the textural properties of applied activated carbon. The roles of acid/base features of activated carbons and of molecular structures of adsorbate molecules have been discussed. The obtained results enabled to estimate the possibility to use the activated carbons in the removal of pharmaceuticals by adsorption.