Mixed valence Fe/Mn bimetallic MOF modified carbon fiber paper cathode designed for the degradation of 2-mercaptobenzothiazole by inhomogeneous Electro-Fenton

2-Mercaptobenzothiazole (MBT), a widely utilized metal corrosion inhibitor in industrial production processes, has become a typical persistent organic pollutant (POP) in the circulating water of coal chemical pipelines. In this study, Fe/Mn bimetallic MOF materials supported on carbon fiber paper (PC) were employed for the first time as an electro-Fenton cathode (Fe/Mn@MPC) in a heterogeneous electro-Fenton system, achieving efficient degradation of MBT. Specifically, this novel cathode enabled 96.35 % removal of MBT within 2 h. The uniformly rough fiber morphology presented by the Fe/Mn@MPC cathode results in an increased electrochemically active surface area and reduced resistance. Remarkably, it maintains a very stable catalytic activity over a wide pH range (3–11) and after 10 h of continuous operation, which confirms that the bimetallic synergistic effect enhances the stability of the system. EPR and quenching experiments identified hydroxyl radicals as the primary active species. Based on HPLC-MS results, MBT degradation pathways involving sulfur oxidation intermediate cleavage and benzothiazole ring detachment were proposed. This work presents a promising cathode design for the treatment of thiol-containing wastewater and offers new insights into the efficient remediation of coal chemical wastewater.