Photochemical transformation and interaction of octachlorodibenzofuran (OCDF) with microplastics in suspended particulate matter-water system

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-05-02 DOI:10.1016/j.watres.2025.123766

Xiaolei Teng, Mengqiang He, Jianqiao Xu, Xiaosheng Tang, Qing Zheng, Zunyao Wang, Ruijuan Qu

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Abstract

Microplastics (MPs) and suspended particulate matter (SPM) are widely present in the aquatic environment, serving as carriers for various pollutants. Understanding the phototransformation behavior of hydrophobic organic pollutants in the presence of coexisting microplastics and SPM is crucial for assessing their environmental fate and potential impacts. In this study, we investigated the photochemical transformation behavior of octachlorodibenzo-p-dioxin (OCDF) in water under simulated solar irradiation, using polypropylene (PP) microplastics and SPM collected from the Pearl River. The results showed that the degradation rate of OCDF increased with the increase of PP content in the system. Experiments using EPR and probe molecules, as well as quenching experiments of reactive species, demonstrated that the presence of PP significantly elevated the concentration of reactive oxygen species (ROS) in the system. Through product analysis, we identified the main degradation pathways of OCDF to involve carbon-oxygen bond breaking, dechlorination and substitution reactions. These pathways were further rationalized and verified through theoretical calculations. In addition, we calculated the reaction energy barriers of OCDF attacked by ROS on the surface of particulate matter. Compared with SPM, the reaction energy barrier for OCDF reacting with •O₂⁻ on the PP surface was significantly reduced, suggesting that PP can enhance the photochemical transformation of OCDF by facilitating the reactivity of ROS. This study provides new insights into the photochemical transformation of hydrophobic organic pollutants mediated by microplastics in real aqueous environments, highlighting the role of MPs in altering the fate and behavior of persistent organic pollutants.

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八氯二苯并呋喃（OCDF）与微塑料在悬浮颗粒物-水体系中的光化学转化及相互作用

微塑料（MPs）和悬浮颗粒物（SPM）广泛存在于水生环境中，是各种污染物的载体。了解微塑料和SPM共存时疏水有机污染物的光转化行为对于评估其环境命运和潜在影响至关重要。在模拟太阳照射下，利用收集自珠江的聚丙烯（PP）微塑料和SPM研究了八氯二苯并对二恶英（OCDF）在水中的光化学转化行为。结果表明，随着体系中PP含量的增加，OCDF的降解率提高。EPR和探针分子实验以及活性物质猝灭实验表明，PP的存在显著提高了体系中活性氧（ROS）的浓度。通过产物分析，我们确定了OCDF的主要降解途径包括碳氧键断裂、脱氯和取代反应。这些途径通过理论计算得到进一步合理化和验证。此外，我们还计算了活性氧攻击OCDF在颗粒物表面的反应能垒。与SPM相比，OCDF在PP表面与•O2−反应的反应能垒明显降低，说明PP可以通过促进ROS的反应性来促进OCDF的光化学转化。本研究为微塑料介导的疏水性有机污染物在真实水环境中的光化学转化提供了新的见解，突出了MPs在改变持久性有机污染物的命运和行为中的作用。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.