Removal of common pharmaceuticals present in surface waters by Amberlite XAD-7 acrylic-ester-resin: Influence of pH and presence of other drugs

►The adsorption of four common pharmaceuticals present in surface-waters, trimethoprim (antibiotic), carbamazepine (antiepileptic), ketoprofen and naproxen (analgesics) onto Amberlite XAD-7 (an acrylic ester resin) has been investigated. ►Adsorption experiments were carried out at different pH conditions and the experimental equilibrium data were fitted to the Langmuir, Freundlich and Dubinin-Radushkevich models. ►The influence of adsorption pH was established for each compound. The investigation indicates that the mean sorption energy (E = 8.3-10.1 kJ mol−1) characterizes a physical adsorption and the surface of the resin is energetically heterogeneous. ►The work studies the effect of the presence of other drugs in solution on the individual adsorption process. The comparison of Freundlich-parameters shows that the adsorption capacity decreases as expected for neutral and acidic drugs and increases for the case of trimethoprim (a basic drug).