Biomass - derived N-doped carbon-supported CuMnO₂ for efficient bisphenol A degradation via visible light - activated...

Bisphenol A (BPA) is an endocrine-disrupting contaminant frequently detected in natural and engineered waters. Visible-light-driven peroxymonosulfate (PMS) activation offers a sustainable and efficient route for BPA abatement. Herein, a novel biomass-derived heterogeneous catalyst, crednerite CuMnO₂ anchored on N-doped rice-straw-lignin-derived carbon (RS-LC(N)), was successfully developed for BPA degradation via visible-light/PMS activation. The catalyst exhibited outstanding kinetics at neutral pH, achieving a pseudo-first-order rate constant (k _obs) of 0.1989 min^-1 under optimized conditions (10 mg L^-1 BPA, 1.0 mM PMS, and a catalyst dose of 1.0 g L^-1). Radical scavenging experiments revealed a dominant radical pathway (SO₄˙^-/˙OH), accompanied by a complementary non-radical contribution involving singlet oxygen (¹O₂) and interfacial electron-transfer mechanisms (ETM). LC-MS/MS (liquid chromatography - tandem mass spectrometry) analysis identified BPA transformation products consistent with two major degradation routes, including radical-mediated hydroxylation/ring cleavage and non-radical oxidation via ¹O₂/ETM, ultimately leading to mineralization. Structural characterization indicated that increasing CuMnO₂ loading moderately reduced the specific surface area while maintaining favorable mass transfer and adsorption characteristics at neutral pH. The catalyst exhibited good tolerance toward complex water matrices, with decreasing k _obs observed from deionized water to natural waters, treated wastewater, and brackish water, in agreement with increasing ionic strength and dissolved organic matter. Excellent stability was demonstrated over five consecutive cycles, with negligible morphological or phase changes and minimal activity loss. Metal leaching remained at the low 10^-2% level and further decreased with repeated use, highlighting the environmental robustness of the catalyst.