Computational study on degradation mechanisms, efficiencies and toxicity of BPA and its analogs in UV/H₂O₂ and Fenton/H₂O₂ systems

Bisphenol A (BPA) and its derivatives, bisphenol E (BPE) and bisphenol F (BPF), are widely used industrial chemicals acting as endocrine disruptors, imposing environmental contamination and health risks. This study leverages density functional theory (DFT) to explore their degradation mechanisms in advanced oxidation processes (AOPs), providing guidance for water treatment. Theoretical calculations were employed to investigate the reaction mechanisms of BPA, BPE and BPF in UV/H₂O₂ and Fenton/H₂O₂ systems, establishing a chemical kinetic model to simulate their degradation processes and efficiencies. Additionally, the subsequent degradation pathways and products of BPE were analyzed, along with the toxic effects of these products on aquatic environments. Thermodynamic analysis was conducted to calculate the initial energy barriers for the reactions of ·OH radicals with BPA and its derivatives. Kinetic calculations showed that at 298 K, the reaction rate constants of BPA, BPE, and BPF with ·OH were 2.75 × 10⁹, 3.87 × 10⁹, and 3.43 × 10⁹ M⁻¹ s⁻¹, respectively. For BPA, the Gibbs free energy barriers (ΔG^≠) for HAA and RAF reactions range from 7.01 to 12.10 kcal/mol and 4.80–9.24 kcal/mol, respectively. Degradation simulation findings showed that in the UV/H₂O₂ system, the concentration of H₂O₂ and the initial pollutant concentration were key factors impacting degradation efficiency. Conversely, in the Fenton/H₂O₂ system, the concentrations of H₂O₂, pollutants, and Fe²⁺ jointly affected the degradation efficiency, © 2025 Elsevier B.V.