Application of CWPO to the treatment of pharmaceutical emerging pollutants in different water matrices with a ferromagnetic catalyst

CWPO has proved to be effective for the treatment of representative pharmaceuticals (sulfamethoxazole, atenolol, metronidazole, diltiazem, trimethoprim and ranitidine) in different water matrices (ultrapure water, surface water, WWTP effluent and hospital wastewater). Complete removal of the pollutants and the aromatic intermediates was achieved using the stoichiometric dose of H2O2, a catalyst (Fe3O4/gamma-Al2O3) load of 2 g L-1, pH 3 and temperature of 50-75 degrees C. Accordingly, the ecotoxicity was reduced to negligible values. The degradation was faster when the pharmaceuticals were together, being the reaction time for the elimination of the most refractory species (metronidazole) shortened from 4h to 1 h. The mineralization of the drugs was fairly different, being the most reactive species those containing several aromatic rings (X-TOC similar to 80%) and the most refractory that bearing an imidazolium ring (X-TOC similar to 35%). The water matrix affected the kinetics of the process but in all cases complete conversion of the drugs was reached within 1 h. The presence of dissolved organic matter (surface water) seemed to promote drugs degradation while the occurrence of inorganic ions (real WTTP and hospital effluents) partially inhibited it due to scavenging effects. Remarkably, the process was successfully operated at the typical concentrations of main micropollutant sources (mu g L-1). (C) 2017 Elsevier B.V. All rights reserved.