Ozonation of ofloxacin in water: By-products, degradation pathway and ecotoxicity assessment

In order to examine the role of ozone (O3) and hydroxyl radicals (OH) in the degradation of ofloxacin, ozonation was performed at pH 2, 7 and 12. In this study, 12 new structures have been proposed for the ozonation by-products detected during the ozonation of ofloxacin. According to the identified ozonation by-products, O3 and OH were found to react with ofloxacin during ozonation. The reaction between ofloxacin and O3 proceeded via hydroxylation and breakdown of heterocyclic ring with unsaturated double-bond. The reaction between ofloxacin and OH generated various by-products derived from the breakdown of heterocyclic ring. Ecotoxicity assessment indicated that ozonation of OFX could yield by-products of greater toxicity compared with parent compounds.