Facilitating Efficient Electro-Fenton Degradation Using a Free-Standing Membrane Electrode with Atomic-Level Fe Dispersion Fabricated by Microwave-Assisted Electrospinning

In response to the urgent demand for efficient organic dye wastewater treatment, this study introduces a novel free-standing electro-Fenton cathode with atomic-level Fe sites (FeBNC/CFM). The MIL-101(Fe) precursor is rapidly synthesized via microwave assistance, followed by the fabrication of a three-dimensional network membrane electrode through electrospinning and programmed temperature-controlled carbonization. X-ray absorption fine structure (XAFS) analysis reveals that the introduction of hexagonal boron nitride (h-BN) promotes atomic-level dispersion, forming Fe-N/Fe-B coordination motifs. This structural innovation significantly enhances hydrophilicity and stability, enabling exceptional performance in electro-Fenton degradation. The cathode rapidly removed 90.6% of Rhodamine B (RhB) within 5 min, achieving a removal efficiency of 98.6% in 10 min. Moreover, it demonstrated excellent performance in removing not only various dyes but also RhB-spiked actual wastewater. Hydroxyl radicals (·OH) and superoxide radicals (·O₂^-) are the primary reactive oxygen species (ROS), with ·OH exhibiting significantly higher reactivity. The active sites and degradation pathways of the RhB molecule are further elucidated via density functional theory (DFT) and liquid chromatography-mass spectrometry (LC-MS) analyses. Notably, toxicity assessment indicates low environmental risk from most of the intermediates, indicating negligible potential for secondary environmental contamination. This study provides a novel strategy for designing high-performance, stable electro-Fenton cathodes showing broad application potential in organic wastewater remediation.