Acid-induced Fe₃O₄ active sites coupled with visible- light-perdisulfate activation efficiently degrades Bisphenol A

The HCl-modified Fe₃O₄ catalyst effectively activated peroxodisulfate (PDS) under visible light irradiation. Within 80 min, under the optimal reaction conditions, the catalyst achieved a degradation efficiency of 92.50 % for Bisphenol A (BPA) and removed 89.82 % of total organic carbon (TOC). The degradation rate was increased by 11.79 % compared with that of the unmodified Fe₃O₄ catalyst. This improvement in performance can be attributed to the enhanced dispersion of the catalyst, the elevated surface potential under visible light irradiation, and synergistic effects between free radicals (SO₄^·-; ·OH,O12) and non-free radicals (e^-, h⁺). After five consecutive cycles, the catalytic activity remained above 84 %, demonstrating excellent recyclability and stability. Additionally, the catalyst exhibited tolerance to various anions and low concentrations of humic acid. The system demonstrates promising broad-spectrum degradation capabilities for phenolic compounds, antibiotics, and other environmental pollutants.