Design of Mixed-Valent Fe/Mn Bimetallic Mof-Modified Carbon Fiber Paper Cathode for Electro-Fenton Degradation of 2-Mercaptobenzothiazole

Abstract

2-Mercaptobenzothiazole (MBT), a widely utilized metal corrosion inhibitor in industrial production processes, has emerged as a typical persistent organic pollutant in coal chemical wastewater. In this study, we successfully synthesized an electro-Fenton cathode derived from a metal-organic framework (MOF), specifically Fe/Mn@MPC, utilizing Fe/Mn bimetallic MOF-modified carbon fiber paper (PC) for the degradation of 2-mercaptobenzothiazole within a non-homogeneous electro-Fenton system. The Fe/Mn bimetallic-modified carbon fiber paper exhibits an enhanced electrochemical surface area and reduced electrical resistance, thereby improving electrocatalytic performance. The Fe/Mn@MPC cathode achieved a remarkable removal efficiency of 96.35% for MBT within 120 minutes and demonstrated excellent stability over five cycles. Burst experiments and electron paramagnetic resonance (EPR) studies confirmed that hydroxyl radicals were the primary active species involved in the MBT degradation process. Furthermore, based on HPLC-MS results, we proposed degradation pathways for MBT that include the cleavage of sulfur oxidation intermediates and the detachment of benzothiazole rings. This study presents a promising cathode design for the electrocatalytic degradation of thiol-containing wastewater, which is anticipated to inspire new strategies for the efficient treatment of coal chemical wastewater.

Keywords: 2-Mercaptobenzothiazole, Modified carbon paper, Bimetallic synergism, Electro-Fenton reaction