Electrochemical activation of peroxymonosulfate with titanium suboxide anode for 4-chlorophenol degradation: Influencing factors, kinetics, and degradation mechanism

Abstract

The unsuitable treatment of 4-chlor (4-CP) in industrial and municipal wastewater will bring a great risk to human health and eco-environment. Traditional adsorption methods for deeply degrading 4-CP suffer from intractable issues containing secondary pollution and resource waste. In this study, electrochemical oxidation coupled with PMS activation process (EO-PMS process) was used to degrade 4-CP via the generated reactive oxygen species (ROS). The increased PMS concentration and current density can effectively remove 4-CP within 20 min, and a high kinetic rate of 0.149 min−1 was obtained. It should be noted that SO4− and OH was dominant active species, and OH played a more important role in degrading 4-CP than SO4−. In addition, the EO-PMS process can remove multiple organic pollutants as well as effective as 4-CP. The EO-PMS process also kept good stability and tolerance with various pH values during continuous five-cycles operations. The analysis of degradation intermediates and DFT calculations confirmed two degradation pathways (Pathway I: P1 → P2 → P3 → P4 and Pathway II: P5 → P6 → P4) due to the attacking of ROS. The study provided a potential insight towards efficient and quick degradation of various organic pollutants through electrochemical advanced oxidation process.