Yu Yingtan, Liu Mengdi, Wang Shimeng, Zhang Chaoxing, Zhang Xue, Liu Li, Xue Shuang
School of Environment, Liaoning University, Shenyang 110036, China.
Molecules. 2024 Sep 24;29(19):4535. doi: 10.3390/molecules29194535.
Polychlorinated naphthalenes (PCNs) are a new type of persistent organic pollutant (POP) characterized by persistence, bioaccumulation, dioxin-like toxicity, and long-range atmospheric transport. Focusing on one type of PCN, monochlorinated naphthalenes (CN-1, CN-2), this study aimed to examine their photodegradation in the environment. In this work, CN-1 and CN-2 were employed as the model pollutants to investigate their photodegradation process under UV-C irradiation. Factors like the pH, initial concentrations of CN-1, and inorganic anions were investigated. Next, the roles of hydroxyl radicals (OH), superoxide anion radicals (O), and singlet oxygen (O) in the photodegradation process were discussed and proposed via theory computation. The results show that the photodegradation of CN-1 and CN-2 follows pseudo-first-order kinetics. Acidic conditions promote the photodegradation of CN-1, while the effects of pH on the photodegradation of CN-2 are not remarkable. Cl, NO, and SO accelerate the photodegradation of CN-1, whereas the effect of SO and CO is not significant. Additionally, the contributions of OH and O to the photodegradation of CN-1 are 20.47% and 38.80%, while, for CN-2, the contribution is 16.40% and 16.80%, respectively. Moreover, the contribution of O is 15.7%. Based on DFT calculations, C4 and C6 of the CN-1 benzene ring are prioritized attack sites for OH, while C2 and C9 of CN-2 are prioritized attack sites.
多氯萘（PCNs）是一种新型持久性有机污染物（POP），具有持久性、生物累积性、二噁英样毒性和大气远距离传输特性。本研究聚焦于一种多氯萘——一氯萘（CN - 1、CN - 2），旨在研究它们在环境中的光降解情况。在这项工作中，采用CN - 1和CN - 2作为模型污染物，研究它们在紫外光C照射下的光降解过程。研究了pH值、CN - 1的初始浓度和无机阴离子等因素。接下来，通过理论计算讨论并提出了羟基自由基（OH）、超氧阴离子自由基（O）和单线态氧（O）在光降解过程中的作用。结果表明，CN - 1和CN - 2的光降解遵循准一级动力学。酸性条件促进CN - 1的光降解，而pH值对CN - 2光降解的影响不显著。Cl、NO和SO加速CN - 1的光降解，而SO和CO的影响不显著。此外，OH和O对CN - 1光降解的贡献分别为20.47%和38.80%，而对CN - 2光降解的贡献分别为16.40%和16.80%。此外，O的贡献为15.7%。基于密度泛函理论（DFT）计算，CN - 1苯环的C4和C6是OH优先攻击的位点，而CN - 2的C2和C9是优先攻击的位点。
