Efficient degradation of Ocuflox in a neutral photo oxidation/reduction system based on the enhanced heterogeneous-homogeneous sulfite-iodide cycle

In this study, photo/oxidation/reduction degradability of Ocuflox (OFX) antibiotic by UV/ZnO/sulfite (UZS) and UV-C/ZnO/KI (UZI) processes was evaluated. The slight amount of OFX degradation by UV / ZnO (UZ) and UV alone was observed after 5 min. The best performance for UZS and UZI processes was observed in the alkaline pH; although, the complete OFX degradation by UZS and UZI was achieved after 5 and 30 min of reaction (81.4% of OFX degradation by UZI was achieved after 5 min). The obtained results from kinetic studies proved this phenomenon, as the robs (mg L−1 min) values for UV alone, UZ, UZI and UZS, were calculated 0.028 mg L−1 min, 0.07 mg L−1 min, 0.56 mg L−1 min and 0.7 mg L−1 min, respectively. In addition the energy consumption and total cost values for system was significantly decreased when sulfite and iodide and sulfite were entered in the photo-catalyst system environment. The scavenging studies indicated both eaq- (generated by reductant agent) and •OH radicals (generated by oxidant agent) have a great importance in the degradation of OFX. In addition, in the final product produced by these processes (UZI and UZS), the degradation of the OFX aromatic compound into linear compounds with high ability in mineralization was demonstrated. Therefore, photo-oxidation-reduction processes due to low time and cost required for degradation of OFX and also high degradation ability of OFX can were applied to degrade the similar pollutants. [Display omitted] •The significant degradation of OFX in the presence of sulfite and KI reductant agents in the photocatalytic reaction environment was observed.•The lower EEO and TCS values proved economically superiority of the UV/ZnO process in the presence of sulfite and KI.•It was proved eaq- and •OH radicals have the significant role in the degradation of OFX by UV/ZnO process in the presence of sulfite and KI.