Photocatalytic performance of Ti/MMO/ZnO at degradation of levofloxacin: Effect of pH and chloride anions

This work investigates the applicability of a new Ti/MMO/ZnO electrode composed to metallic mixture oxides of ruthenium and titanium (MMO) and zinc oxide electrodeposited in the photoelectrocatalytic treatment of synthetic wastes polluted with the antibiotic levofloxacin (LFX) and chlorine anions. This work try to shed light, at a low Technology Readiness Level (TRL), of the mechanisms which may be involved in the degradation of antibiotics in real wastes containing high concentrations of chlorides, such as urine, in the absence of other disturbing inputs. Results show that the degradation efficiency depended on the pH of the waste and a more pronounced synergistic effect between Ti/MMO/ZnO and UVC light was obtained at acidic and neutral pH, leading to higher rates of antibiotic removal with the subsequent formation of inorganic ions NH4+ and NO3−. The large formation of hydroxyl radicals from the photo-generated charges in Ti/MMO/ZnO, and the reactive chlorine species produced from the homolysis of hypochlorous acid/hypochlorite, are used to explain the oxidation mechanism. In addition, results indicate that Ti/MMO/ZnO is an excellent photocatalyst for the degradation under acidic conditions in wastes containing chloride anions of persistent pollutants at relatively low concentrations.