Assessment of degradation characteristic and mineralization efficiency of norfloxacin by ionizing radiation combined with Fenton-like oxidation

In this study, the degradation of norfloxacin was investigated by ionizing radiation combined with Fenton-like oxidation in order to enhance the degradation and mineralization of norfloxacin. The result showed that the removal efficiency of norfloxacin was 100%, 81.8%, 64.5%, 51.9%, and 45.6% at 0.4 kGy radiation when its concentration was 5, 10, 20, 30, and 40 mg/L. Norfloxacin could be completely degraded over pH range of 3.06–10.96 at 2 kGy radiation. The presence of inorganic anions had obvious influence on the degradation of norfloxacin, which decreased from 89.4% to 59.0%, 76.9%, 86.9%, 88.7% and 83.9% in the presence of 10 mmol/L CO 3 2– , HCO 3 – , NO 3 – , SO 4 2 – , Cl – , HPO 4 2 – . The removal efficiency of norfloxacin decreased from 100% to 11.8%, 27.6% and 89.3% in the presence of peptone, glucose, and humic acid . The addition of Fenton-like catalysts, such as magnetite and goethite , could improve the mineralization ratio of norfloxacin because they could decompose hydrogen peroxide generated during the radiation process, to form hydroxyl radicals , leading to the enhancement of removal efficiency of norfloxacin. Finally, the intermediate products of norfloxacin degradation were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF), and the degradation pathway was proposed.