Peroxydisulfate activation by magnetic nanoflakes zero-valent iron/graphitized carbon composites for norfloxacin removal: Synergistic effect of 1O2 with surface Fe(IV)

The recycling and utilization of waste biomass resources have attracted widespread attention due to their enormous potential economic value. In this study, a magnetic zero-valent iron nanoflake-modified graphitic mesoporous carbon composite (Fe@SBCx) was prepared using ultrasound-assisted impregnation and pyrolysis strategies, and employed as an efficient peroxydisulfate (PDS) activator for the removal of the antibiotic norfloxacin (NOR) from water. The Fe@SBC 1.13 /PDS system exhibited excellent oxidation performance, achieving nearly complete removal (>99 %) of 10 mg/L NOR within 25 min. Singlet oxygen ( 1 O 2 ) and ferryl iron species (Fe(IV)) were identified as the major oxidative reactive species in the system. The formation of electron donor–acceptor complexes during the reaction facilitated the decomposition of PDS and the generation of oxidative species. Fe@SBC 1.13 demonstrated satisfactory recyclability and catalytic stability. Based on density functional theory (DFT) calculations and intermediate product analysis, the degradation pathways of NOR were proposed. Moreover, the toxicity evaluation results revealed a lower bacterial cytotoxicity in the treated drainage. Overall, this study not only enriches the theoretical research on the degradation mechanisms of fluoroquinolone antibiotics in the environment but also provides a viable approach for developing highly efficient and carbon–neutral catalysts.