Unveiling the optical and molecular characteristics of aging microplastics derived dissolved organic matter transformed by UV/chlor(am)ine oxidation and its potential for disinfection byproducts formation

Huiming Zheng; Sinong Huang; Jiahui Huang; Hanxuan Zeng; Mengyuan Xu; Anhong Cai; Shiqing Zhou; Xiaoyan Ma; Jing Deng

doi:10.1016/j.jhazmat.2024.136440

Unveiling the optical and molecular characteristics of aging microplastics derived dissolved organic matter transformed by UV/chlor(am)ine oxidation and its potential for disinfection byproducts formation

J Hazard Mater. 2024 Nov 8:480:136440. doi: 10.1016/j.jhazmat.2024.136440. Online ahead of print.

Authors

Huiming Zheng¹, Sinong Huang¹, Jiahui Huang¹, Hanxuan Zeng², Mengyuan Xu², Anhong Cai³, Shiqing Zhou⁴, Xiaoyan Ma⁵, Jing Deng⁶

Affiliations

¹ College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China.
² College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China; Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Hangzhou 310023, China.
³ National and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China.
⁴ College of Civil Engineering, Hunan University, Changsha 410082, China.
⁵ College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China; Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Hangzhou 310023, China. Electronic address: mayaner620@163.com.
⁶ College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China; Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Hangzhou 310023, China. Electronic address: zjut_djing@163.com.

PMID: 39541889
DOI: 10.1016/j.jhazmat.2024.136440

Abstract

The investigations into the existence and behavior of microplastics (MPs) in water environment were widely conducted, while the characteristics of dissolved organic matter derived from MPs (MPs-DOM) during advanced oxidation have garnered comparatively little attention. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was employed along with multiple statistical analyses to gain a deeper understanding of the conversion of MPs-DOM in UV/chlor(am)ine advanced oxidation processes (AOPs). The diverse treatments exhibited varying degrees of augmentation in both aging and fragmentation of MPs with the order of UV/Cl₂ > UV > UV/NH₂Cl. The fragmentation degree of MPs upon two UV-based AOPs (UV-AOPs) was dependent on their monomer chemical structure. The highest TOC values of three MPs-DOM were observed after UV/Cl₂ AOP and the lowest after UV/NH₂Cl AOP. Polyvinyl chloride (PVC) displayed a greater release of MPs-DOM under varying leaching conditions. UV/Cl₂ AOP favored the reaction with saturated MPs-DOM, while UV/NH₂Cl AOP reduced unsaturated MPs-DOM, alleviating disinfection byproducts (DBPs) formation after chlorination. The precursors generated by UV/Cl₂ AOP owned lower H/C, higher modified aromatic index (AI_mod), and lower molecular weight (MW) products after chlorination. PVC-DOM with fewer CH₂ groups was more reactive. -H₂O, +O and -CH₂ reactions dominated in PVC-DOM (CHO compounds), while -2H, +O, -CH₂ did in PVC-DOM (CHON compounds). The dominant chlorine addition/substitution reactions occurred in PVC-DOM treated by UV/Cl₂ AOP, identifying 195 Cl-DBPs with 220 precursor-product pairs. Mass difference analyses showed that +2H and +O reactions were the most frequent of the 24 reaction types.

Keywords: Disinfection byproducts; Dissolved organic matters; FT-ICR-MS; Microplastics; UV/chlor(am)ine.