Two-dimensional manganese-iron bimetallic MOF-74 for electro-Fenton degradation of sulfamethoxazole

This study reported a novel application of Mn0.67Fe0.33-MOF-74 with two-dimensional (2D) morphology grown on carbon felt as a cathode for efficiently removing antibiotic sulfamethoxazole in the heterogeneous electro-Fenton system. Characterization demonstrated the successful synthesis of bimetallic MOF-74 by a simple one-step method. Electrochemical detection showed that the second metal addition and morphological change improved the electrochemical activity of the electrode and contributed to pollutant degradation. At pH 3 and 30 mA of current, the degradation efficiency of SMX reached 96% with 12.09 mg L-1 H2O2 and 0.21 mM center dot OH detected in the system after 90 min. During the reaction, electron transfer between =Fe-II/III and =Mn-II/III promoted divalent metal ions regeneration, which ensured the continuation of the Fenton reaction. Two-dimensional structures exposed more active sites favoring center dot OH production. The pathway of sulfamethoxazole degradation and the reaction mechanisms were proposed based on the intermediates identification by LC-MS and radical capture results. High degradation rates were still observed in tap and river water, revealing the potential of Mn0.67Fe0.33-MOF-74@CF for practical applications. This study provides a simple MOF-based cathode synthesis method, which enhances our understanding of constructing efficient electrocatalytic cathodes based on morphological design and multi-metal strategies.

Automated summary

This study reported a novel application of Mn0.67Fe0.33-MOF-74 with two-dimensional morphology grown on carbon felt as a cathode for efficiently removing antibiotic sulfamethoxazole in the heterogeneous electro-Fenton system. Electrochemical detection showed that the second metal addition and morphological change improved the electrochemical activity of the electrode and contributed to pollutant degradation. The pathway of sulfamethoxazole degradation and the reaction mechanisms were proposed based on the intermediates identification by LC-MS and radical capture results.