Degradation of 2,4-DCP using persulfate and iron/E-carbon micro-electrolysis coupling system

摘要

The greenhouse gas carbon dioxide (CO2) was converted to a novel CO2 conversion material (electrolytic carbon, EC) by molten salt electrochemical conversion, which served as the carbon source to prepare an iron–carbon composite (Fe–EC). The composite was used to activate persulfate (PS) and degrade 2,4-dichlorophenol (2,4-DCP) in an aqueous solution. The effects of several essential operating parameters such as PS dosage and pH on 2,4-DCP degradation were investigated. The removal efficiency of 2,4-DCP (20 mg L–1) was 97.8% in the presence of Fe–EC (50 mg L–1) and PS (1 mmol L–1). Moreover, the average % reaction stoichiometric efficiency (RSE) (calculated for all selected times 5–60 min) was maintained at 23.07%. Electron paramagnetic resonance (EPR), classical radical scavenging experiments, and density functional theory (DFT) calculations were integrated for a mechanistic study, which disclosed that the active species in the system were identified as SO4⦁–, •OH, and O2⦁−. Moreover, the iron–carbon micro-electrolysis/PS (ICE-PS) system had a high tolerance to a wide range of pH, which would provide theoretical guidance for the treatment of organic pollutants in practical industrial wastewater.