Efficient electrocatalytic removal of tetracycline by a MoS2/Fe-Mn biochar three-dimensional particle electrode: Interfacial redox behavior and degradation mechanisms

A three-dimensional particle electrode was established by integrating MoS 2 with nitrogen-doped Fe Mn biochar (MoS 2 /NFMB-1.0), enabling efficient electrochemical oxidation of tetracycline (TCH) in aqueous environments. Under optimized conditions, the MoS 2 /NFMB-1.0 achieved a TCH removal efficiency of 96.60%, substantially outperforming the two-dimensional electrode system. After five successive cycles, the degradation efficiency remained at 89.65%. The MoS 2 /NFMB-1.0 also promoted stronger mineralization, with a TOC removal of 74.31%, outperforming NFMB (65.21%), MoS 2 (38.43%). Reactive oxygen species (ROS) analysis revealed that the reaction was primarily driven by 1 O 2 (39.37%), accompanied by O 2 ·- (31.73%) and ·OH (28.90%). The incorporation of MoS 2 facilitated the Fe/Mn redox cycle and ensured continuous ROS generation throughout the reaction. The 3D/MoS 2 /NFMB-1.0 system maintained strong reactivity across a broad pH range from 3 to 11 and remained effective toward several representative antibiotics. Liquid chromatography-mass spectrometry (LC-MS) further clarified the transformation pathways of TCH, while ecotoxicity prediction confirmed that the toxicity of intermediates progressively declined as the reaction proceeded. These results highlight the significant potential of the MoS 2 /NFMB-1.0-based 3D particle-electrode system for future electrochemical water treatment.