Fe-Cu@BC catalyst activated PMS for typical organic pollutants degradation: Catalytic performance and reaction mechanism

An iron–copper bimetallic biochar catalyst (Fe-Cu@BC) was synthesized to establish a heterogeneous peroxymonosulfate (PMS) activation system aimed at improving the removal of typical organic pollutants in drinking water sources. The physicochemical properties of the catalyst, the catalytic performance, reactive species generation, pollutant degradation pathways, and impacts on dissolved organic matter (DOM) transformation were systematically investigated. Under the optimized conditions, a humic acid (HA) removal efficiency of 66.28% was achieved, which was attributed to the cooperative redox behavior of Fe and Cu species. Radical quenching experiments and electron paramagnetic resonance (EPR) spectroscopy confirmed the simultaneous generation of OH, and 1 O 2 . A quantitative chemical probe-based kinetic analysis clarified the contributions of individual reactive species, and pollutant degradation proceeded through the combined action of OH/-driven radical oxidation and 1 O 2 -mediated selective oxidation. Advanced characterization using three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) showed that the system altered the molecular composition of DOM in both conventionally treated and advanced-treated effluents, converting high-molecular-weight, reduced components into low-molecular-weight, more oxidized intermediates. This work provides an effective catalytic strategy for the deep treatment of organic-contaminated water using carbon-based bimetallic activators.