Inactivation of antibiotic resistant E. coli and degradation of chlortetracycline in iron-carbon micro-electrolysis coupled with peroxydisulfate system

The iron-carbon (Fe-AC) micro-electrolysis coupled with peroxydisulfate (PDS) process was applied for the degradation of chlortetracycline hydrochloride (CTC) and inactivation of antibiotic resistant bacteria (ARB). The cathode, anode, and PDS in the primary cell formed a charge transport redox system, which ensured the continuous generation of active species. The optimal degradation rate of CTC could reach 82.26% by the optimization of parameters such as PDS concentration, Fe concentration, and degradation time by response surface method. The possible degradation pathways of CTC were proposed by LC-MS and density functional theory (DFT) calculations. Moreover, the active species produced by Fe-AC/PDS system severely damaged the cell structure of antibiotic resistant E. coli, resulted in cell membrane atrophy, surface collapse, and cell contents leakage. The analysis results of malondialdehyde, ATP and antioxidant enzymes activity also verified the oxidative damage of E. coli cells in the catalytic system. Free radical quenching and electron paramagnetic resonance spectroscopy confirmed the indelible roles of SO4 center dot- in ARB inactivation. The findings provide a new perspective for preventing the spread of antibiotic resistance in aqueous environments.