The heterogeneous reactions of ROS with BPA/BPS: A multiscale simulation study of the effects of aerosol droplets and...

Bisphenol compounds, as typical emerging pollutants, have attracted widespread attention, but their degradation and transformation mechanisms at multiphase interfaces and environmental fate still require further research. In this study, we selected bisphenol A (BPA) and bisphenol S (BPS) as model compounds to investigate their interfacial properties and reaction mechanisms on aerosol droplets and mineral dust surfaces. A multiscale computational model combining molecular dynamics simulations, quantum chemistry calculations, and quantitative structure-activity relationship analysis is proposed, which reveals the interfacial properties of BPA/BPS in multiple media and the reaction mechanisms of their oxidation by reactive oxygen species. Overall, BPA/BPS and hydroxyl radical (•OH) show a significant aggregation tendency at the gas-water interface, and their reaction rate at the gas-water interface is higher than that in the gas and water phases. BPA/BPS adsorption on the gas-Al₂O₃ interface is significantly greater than that on the gas-SiO₂ interface, with the optimal adsorption orientation being where the two hydroxyl groups of the bisphenol compound face the Al₂O₃ interface. For •OH and ozone (O₃), gas-solid interface effects promote the reaction process. However, For the oxidation reaction of BPA/BPS induced by singlet oxygen (¹O₂), the reaction rate in the water phase is the highest. Our findings are of significant importance for understanding the transformation, fate, and degradation mechanisms of bisphenol pollutants, offering critical evidence for elucidating pollutant-aerosol interaction mechanisms and improving the interface chemical models.