Highly Efficient Florfenicol Removal via Nitrogen-Doped Zero-Valent Iron/Carbon Composites Activated with Peroxodisulfate: Mechanisms and Pathways

Florfenicol (FF) accumulation in aquatic environments is a critical concern due to ecosystem disruption, microbial resistance, and health risks.While zero-valent iron (ZVI) is recognized for antibiotic remediation, studies on FF removal using nitrogendoped ZVI-based materials activated by peroxodisulfate (PDS) and their degradation mechanisms are limited.This study synthesizes N-doped ZVI/C-1 via pyrolysis of ironbased metal-organic frameworks (MOFs), where organic ligands form a carbon matrix supporting ZVI particles and incorporate nitrogen atoms.The resulting N-doped ZVI/C-1 exhibits increased defect density, higher specific surface area, and improved hydrophobicity compared to ZVI/C.Electrochemical analyses further reveal that Ndoped ZVI/C-1 possesses superior corrosion resistance, faster charge transport, and reduced hydrogen evolution activity.Consequently, N-doped ZVI/C-1 achieves a high FF removal efficiency of 96.0% within 30 minutes when activated by PDS.Mechanistic investigations indicate that the dominant degradation involves the generation of OH and SO4 radicals, resulting in higher dechlorination and defluorination capacities compared to ZVI/C.Identified degradation pathways include C-Cl and C-F bond cleavage, C=O addition, and benzene ring decomposition, leading to a gradual reduction in FF toxicity.This study presents a promising strategy for FF removal and enhances the understanding of degradation mechanisms utilizing nitrogen-doped ZVIbased materials.