Adsorptive removal of diclofenac from ultrapure and wastewater: a comparative assessment on the performance of a polymeric resin and activated carbons

摘要

This work aimed to compare the adsorptive removal of diclofenac from ultrapure and wastewater by different adsorbents. Batch kinetic and equilibrium experiments were carried out using two different activated carbons (GPP20 and WP70, from Chemviron Carbon) and a non-ionic polymeric resin (SP207, from Resindion). The pseudo-second-order equation fitted the kinetic experimental results and the corresponding k(2) (gmg(-1)min(-1)) determined for the activated carbons was one order of magnitude higher than for the polymeric resin. The equilibrium results were fitted by the Langmuir-Freundlich isotherm. The determined maximum adsorption capacity (Q(m), mgg(-1)) and the adsorbent-adsorbate affinity parameter (K-LF, mgg(-1) (mgL(-1))(-1)) were one order of magnitude higher for the activated carbons than for the polymeric resin. With respect to the influence of the aqueous matrix, both the k(2) and the Q(m) remained the same in ultrapure as in wastewater. Differently, the K-LF showed one order of magnitude higher values in waste than in ultrapure water. WP270 displayed the best adsorptive performance providing 0.00106gmg(-1)min(-1) (k(2)), 315mgg(-1) (Q(m)), and 1.7mgg(-1) (mgL(-1))(-1) (K-LF) for the adsorption of diclofenac from wastewater. These results support the practical application of activated carbon for the removal of diclofenac during the tertiary treatment of waste effluents.