Potential degradation of norfloxacin using UV-C/Fe2+/peroxides-based oxidative pathways

Abstract

• Different peroxides-based oxidative pathways were compared towards NOR degradation. • The peroxide HSO 5 − performed best in the degradation of NOR under UV-C and Fe 2+ . • The peroxides yield ● OH and SO 4 ●− under activation by UV-C and Fe 2+ activation. • The ● OH and SO 4 ●− scavengers inhibited degradation of NOR. • Degradation products and ecotoxicities of NOR as well as its DPS were estimated. The removal of norfloxacin (NOR), a widely used pharmaceutical and emerging water pollutant, was studied using UV-C and Fe 2+ catalyzed peroxides-based oxidative processes (e.g., UV-C/Fe 2+ /H 2 O 2 , UV-C/Fe 2+ /S 2 O 8 2− and UV-C/Fe 2+ /HSO 5 − ) and compared with UV-C and UV-C/Fe 2+ . The UV-C and UV-C/Fe 2+ degraded NOR to 38 and 55%. However, use of peroxides, i.e., H 2 O 2 , S 2 O 8 2− , HSO 5 − with UV-C and UV-C/Fe 2+ promoted NOR %degradation to 75, 83, and 90% using [peroxides] 0 = 50 mg/L, [Fe 2+ ] 0 = 1 mg/L, and [NOR] 0 = 10 mg/L, respectively. The significant impact of peroxides on NOR degradation was due to their decomposition into ● OH and SO 4 ●− which showed high activity towards NOR degradation. The ● OH and SO 4 ●− formation from peroxides decomposition and their contribution in NOR degradation was verified by different scavenger studies. Among the UV-C/Fe 2+ /peroxides processes, UV-C/Fe 2+ /HSO 5 − showed better performance. The changing concentrations of peroxides, Fe 2+ , and NOR affected degradation of NOR. The use of different pH and inorganic anions also influenced NOR degradation. The degradation pathways of NOR were established and analyzed acute as well as chronic toxicities of NOR and its DPs.