High levofloxacin removal in the treatment of synthetic human urine using Ti/MMO/ZnO photo-electrocatalyst

Abstract

In this work, the degradation of the antibiotic levofloxacin (LFX) in synthetic urine by photoelectrolysis with a ZnO film-based electrode and a mixture of titanium and ruthenium metal oxides (Ti/MMO/ZnO) was investigated. From the morphological characterization of the Ti/MMO/ZnO electrode, it was found that it has porous nanostructures that are associated with its high surface area, contributing to the good photocatalytic activity of the material. Degradation assays showed that LFX removal in urine matrix is not selective, as some urine constituents such as creatinine and uric acid were also degraded with the antibiotic during photolysis and photoelectrolysis. Electrolysis was not able to degrade LFX and this may be related to the low concentration of oxidants generated in this process, due to the low applied potential (0.2 V). Although a significant synergistic effect between light and photoelectrocatalyst on LFX degradation was not observed, photoelectrolysis with Ti/MMO/ZnO was able to degrade more reaction intermediates at the end of the process without the formation of recalcitrant chlorine species, such as the ClO3–, when compared to photolysis. This shows that it is possible to remove antibiotic LFX from the urine matrix with high efficiency and without the formation of hazardous chlorine compounds using the Ti/MMO/ZnO photoanode.