Environment Research Institute, Shandong University, Qingdao, 266237, PR China.
School of Chemistry and Chemical Engineering, Heze University, Heze, 274015, PR China.
Environ Res. 2020 Sep;188:109713. doi: 10.1016/j.envres.2020.109713. Epub 2020 Jun 1.
The pharmaceutical and personal care products (PPCPs) in aquatic environment have aroused more interest recently. Many of them are hard to degrade by the typical biological treatments. Diclofenac (DCF), as a significant anti-inflammatory drug, is a typical PPCP and widely existed in water environment. It is reported that DCF has adverse effects on aquatic organisms. This work aims to investigate the mechanism, kinetics and ecotoxicity assessment of DCF transformation initiated by O in aqueous solution, and provide a solution to the degradation of DCF. The O-initiated oxidative degradations of DCF were performed by quantum chemical calculations, including thirteen primary reaction pathways and subsequent reactions of the Criegee intermediates with HO, NO and O. Based on the thermodynamic data, the kinetic parameters were calculated by the transition state theory (TST). The total reaction rate constant of DCF initiated by O is 2.57 × 10 M s at 298 K and 1 atm. The results show that the reaction rate constants have a good correlation with temperature. The acute and chronic toxicities of DCF and its degradation products were evaluated at three different trophic levels by the ECOSAR program. Most products are converted into less toxic or harmless products. Oxalaldehyde (P3) and N-(2,6-dichlorophenyl)-2-oxoacetamide (P6) are still harmful to the three aquatic organisms, which should be paid more attention in the future.
最近，水体中的药物和个人护理用品（PPCPs）引起了更多的关注。其中许多物质很难通过典型的生物处理方法进行降解。双氯芬酸（DCF）作为一种重要的抗炎药物，是一种典型的 PPCP，广泛存在于水环境中。据报道，DCF 对水生生物具有不良影响。本工作旨在研究 O 在水溶液中引发 DCF 转化的机制、动力学和生态毒性评估，为 DCF 的降解提供解决方案。通过量子化学计算，对 DCF 的 O 引发氧化降解进行了研究，包括 Criegee 中间体与 HO、NO 和 O 的十三种主要反应途径和后续反应。基于热力学数据，通过过渡态理论（TST）计算了动力学参数。在 298 K 和 1 atm 下，O 引发的 DCF 的总反应速率常数为 2.57×10M s。结果表明，反应速率常数与温度有很好的相关性。利用 ECOSAR 程序对 DCF 及其降解产物在三个不同营养层次的急性和慢性毒性进行了评价。大多数产物转化为毒性较小或无害的产物。草醛（P3）和 N-（2,6-二氯苯基）-2-氧代乙酰胺（P6）对三种水生生物仍有危害，在未来应予以更多关注。
