Insight into the efficient degradation of 2,4,6-trichlorophenol by a three-electrode simultaneous oxidation-reduction system: kinetics and mechanism

This study developed a three-electrode system that integrates electro-Fenton (EF) and electrocatalytic hydrodechlorination (ECH) technologies, enabling simultaneous redox processes for the efficient degradation of chlorophenolic pollutants while minimising the formation of chlorine-containing by-products. The system includes a Pd/Ni foam electrode for enhanced hydrodechlorination and an acetylene black/Fe₃O₄ electrode for in-situ H₂O₂ generation and activation to produce hydroxyl radicals. The innovation of this work lies in the novel combination of electrochemical Fenton oxidation and electrocatalytic hydrodechlorination within a single system, offering a more efficient and environmentally friendly solution for chlorophenol degradation. Compared to the EF system, the three-electrode setup significantly improved the degradation efficiency of 2,4,6-trichlorophenol (2,4,6-TCP) and reduced by-product formation. Additionally, it showed less sensitivity to changes in current intensity and pH, offering a more robust and effective approach for water treatment. However, it is worth noting that the catalytic efficiency of the three-electrode (oxidation-reduction) system decreases gradually as the number of electrolytic cycles increases due to catalyst loss on the electrode surface. Finally, the degradation experiments of 2,4-DCP indicated that the three-electrode (oxidation-reduction) system holds considerable potential for the management of chlorophenol pollutants.