Co3O4/carbon felt three‐dimensional electrode promoted electrocatalytic oxidation – peroxymonosulfate system for p‐nitrophenol degradation: effect of radical and non‐radical mechanisms

Abstract

AbstractBACKGROUNDConventional electrochemical oxidation (EO) processes do not easily activate peroxymonosulfate (PMS) and are susceptible to the effects of electrode size, material and large‐distance two‐dimensional (2D) electrode structures, resulting in low mass transfer efficiency and low electrolytic productivity, limiting their ability to degrade pollutants. It is still a challenge to design and prepare a system and materials to enhance the activation of PMS and the EO process.RESULTSCo3O4‐loaded carbon felt three‐dimensional (3D) electrode material (Co/CF) was prepared and used to construct a 3D electrocatalytic synergistic system (EO‐Co/CF‐PMS). The system combined the advantages of bipolar electrochemistry, three‐dimensional electrochemistry and advanced oxidation processes based on sulfate radical (SR‐AOPs) to facilitate the activation of PMS for degradation of p‐nitrophenol (PNP) in water. In addition, the synergistic system showed excellent pollutant degradation performance, achieving 89.51% PNP degradation in 10 min with an energy consumption of 0.4255 kWh m−3. After being used for four consecutive cycle experiments, the synergistic system still achieved 83% PNP removal. Besides, the EO process also facilitated the Co cycle, resulting in a continuous and efficient degradation of the pollutants. The effects of experimental parameters (initial pH, PMS dose, and applied voltage) on PNP elimination were determined. The results of a reactive oxygen species scavenging experiment and electron spin resonance analysis showed that ·OH, SO4·−, and 1O2 all played a major role in the PNP elimination process.CONCLUSIONSThe research demonstrated that the composite catalyst Co/CF improved the property of the EO process for catalyzing PMS and thus enlarged the practical application of AOPs in pollutant degradation in aqueous solution. © 2022 Society of Chemical Industry (SCI).