Efficient electrochemical degradation of tetrabromobisphenol A using MnO2/MWCNT composites modified Ni foam as cathode: Kinetic analysis, mechanism and degradation pathway

In this study, MnO2/MWCNT hybrids, prepared using a solvothermal method, were coated onto Ni foam and then used as a cathode for tetrabromobisphenol A (TBBPA) degradation. The reaction was confirmed to exhibit the pseudo first-order kinetics. Compared with the original Ni foam cathode, the fabricated electrode exhibited higher catalytic activity, attributed to its strong cross-linking and ability to produce catalytic free radicals. Radical scavenger experiments revealed that O-2(-center dot) and (OH)-O-center dot were involved in the decomposition of TBBPA. The effects of current density, pH, catalyst dosage, and initial TBBPA concentration on removal efficiency were further studied. An optimal removal rate of 98.3% was achieved while the rate constant reached values up to 0,07293 min(-1) and the debromination rate was more than 75.4% within 60 min, The electrode showed high catalytic performance and low catalyst loss after 10 cycles, indicating its excellent stability and reusability. The probable mechanism and pathway of TBBPA degradation were suggested based on the analysis of intermediate products. It could be inferred that the decomposition of TBBPA involved C-C bond breaks (oxidation) and debromination (reduction). The MnO2/MWCNT-Ni foam could be a promising cathode material for electrochemical degradation of halogenated organic compounds.