Advanced Oxidation Processes based on the use of UVC and simulated solar radiation to remove the antibiotic tinidazole from water

The objective of this study was to analyse the effectiveness of different Advanced Oxidation Processes based on solar and ultraviolet C radiation to remove the antibiotic tinidazole (TNZ) from water. Specifically the systems studied were: UVC, solar radiation, UVC/H2O2, solar/H2O2, UVC/K2S2O8, solar/K2S2O8, UVC/photo-Fenton and solar/photo-Fenton. Some aspects of these processes such as the degradation percentage of TNZ, its mineralisation degree, and the degradation products, were analysed. The direct photodegradation of TNZ showed low yields, with a removal percentage lower than 50%. With the UVC/H2O2 system, the percentage of TNZ degraded increased with the H2O2 concentration, but when solar radiation was used, the addition of H2O2 did not favour the process efficiency. The UVC/K2S2O8 system was more efficient than UVC/H2O2 for TNZ degradation. The presence of K2S2O8 in the solar photodegradation also enhanced TNZ degradation in comparison to the direct photolysis process. In the photo-Fenton systems, for both UVC and solar radiations, high levels of TNZ degradation and mineralisation were obtained. Therefore, the photo-Fenton systems are the most recommended to treat water contaminated with TNZ. Some clues of the mineralisation process appear from the degradation products detected by means of coupled ultra-pressure liquid chromatography and high-resolution mass spectrometry.