Dehalogenation performance of florfenicol by bimetallic iron-cobalt based on direct electron transfer under electric field

Dehalogenation of halogenated antibiotics is an effective pretreatment method aimed to eliminate the toxicity. In this study, a novel electrode was developed utilizing single-step electrodeposition for the in-situ generation of bimetallic iron-cobalt nanoparticles on copper foam (CF). The synthesized cathode material (Fe@Co/CF) was utilized for the electrochemical reductive dehalogenation of florfenicol (C₁₂H₁₄Cl₂FNO₄S, FLO), a representative halogenated antibiotic. The presence of a positive charge on the surface of the bimetallic iron-cobalt was proved by density functional theory (DFT) calculations, enhancing the adsorption of the C-Cl bond and reducing the activation energy. The removal of FLO was ＞99 % under the optimal conditions of 10 mA and pH 6.0 by Fe@Co/CF and the dechlorinating efficiency of FLO was approximately 83 %, which was significantly superior to other cathode materials. Great treatment performance on Fe@Co/CF for other chlorinated antibiotics was demonstrated. The primary mechanism for FLO dehalogenation by Fe@Co/CF was direct electron transfer (DET), which was augmented by the synergistic effect of the bimetallic iron-cobalt. During the electrochemical reductive dehalogenation, FLO was sequentially decomposed to C₁₂H₁₄ClFNO₄S and then to C₁₂H₁₄FNO₄S, significantly reducing biotoxicity. After practical water treatment and cycles, high treatment efficiency of Fe@Co/CF was maintained. The developed electrode for the dehalogenation of halogenated antibiotics in this study has demonstrated great potential for dechlorinating halogenated pollutants in wastewater.