Formation of Secondary Oxidation Products from Nano-plastics in Drinking Water Treatment Processes and Assessment of Their Potential Toxicity

Document Type : Original Article

Author

Department of Civil and Environmental Engineering, Water and Wastewater Engineering, Islamic Azad University, Ahvaz Branch, Ahvaz, Iran

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.

Graphical Abstract

Formation of Secondary Oxidation Products from Nano-plastics in Drinking Water Treatment Processes and Assessment of Their Potential Toxicity

Keywords

Subjects

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