Journal of Chemical Engineering and Energy Materials

Abstract Nano-plastics (NPs) have emerged as a critical concern in drinking water treatment due to their persistence, mobility, and potential to generate toxic transformation products during disinfection. This study provides a comprehensive investigation into the formation of secondary oxidation products from polystyrene Nano-plastics (PS-NPs) during oxidative water treatment processes and evaluates their associated toxicity risks. The research integrates experimental analysis of degradation pathways under ozonation, chlorination, and UV-based advanced oxidation processes (AOPs) with systematic toxicity assessment using luminescent bacteria bioassays. Results demonstrate that ozonation achieves 99.9% molecular weight degradation and 42.7% mineralization of PS-NPs within 240 minutes, while chlorination exhibits substantially lower efficacy with only 7.1% molecular weight degradation. However, the formation of oxygen-containing intermediates including formic acid, phenol, acetophenone, and hydroquinone during ozonation raises concerns regarding secondary contamination. UV/PMS treatment achieved 63.9% mineralization but resulted in 98.19% inhibition of luminescent bacteria, indicating significant toxicity of degradation intermediates. By contrast, UV/NaClO showed lower toxicity (2.97% inhibition) but limited mineralization efficiency (7.0%). These findings underscore the critical knowledge gap regarding the trade-off between NP degradation efficiency and the formation of toxic secondary products, highlighting the urgent need for integrated treatment strategies that address both NP removal and byproduct toxicity.