Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP(3)), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Chemosphere. 2016 Feb;144:628-34. doi: 10.1016/j.chemosphere.2015.09.039. Epub 2015 Sep 21.
Polychlorinated biphenyls (PCBs) pose potential ecological risk because of their high toxicity and carcinogenicity. Photodegradation, which is an important process for the removal of PCBs, is greatly influenced by the cosolvent and catalyst. Hence, it is important to explore their effects on the photodegradation behavior of PCBs. In this study, 2,4,4'-trichlorobiphenyl (PCB28) was selected as a model compound, and the effects of two typical cosolvents, namely acetone and ethanol, and TiO2 catalyst on the distributions of free radicals and intermediates were investigated. Interestingly, the TiO2 catalyst did not promote PCB28 photodegradation. Moreover, the free radical distribution was greatly influenced in the presence of the TiO2 catalyst, while was only slightly affected in its absence by the cosolvent kinds. The main photodegradation pathways are proposed on the basis of the distribution of detected intermediates, which were significantly regulated by both the cosolvent and TiO2 catalyst. The results provide novel insights into the photodegradation of PCBs and may have important implications for choosing cosolvent in desorbing soil PCBs and consequently enhancing PCBs degradation.
多氯联苯（PCBs）由于其高毒性和致癌性而构成潜在的生态风险。光降解是去除 PCBs 的重要过程，而共溶剂和催化剂对其有很大的影响。因此，探索它们对 PCBs 光降解行为的影响非常重要。在本研究中，选择 2,4,4'-三氯联苯（PCB28）作为模型化合物，考察了两种典型共溶剂丙酮和乙醇以及 TiO2 催化剂对自由基和中间产物分布的影响。有趣的是，TiO2 催化剂并没有促进 PCB28 的光降解。此外，TiO2 催化剂的存在极大地影响了自由基的分布，而共溶剂种类的存在对自由基的分布影响较小。基于检测到的中间产物的分布，提出了主要的光降解途径，共溶剂和 TiO2 催化剂都对其有显著的调节作用。研究结果为 PCBs 的光降解提供了新的见解，对于选择共溶剂解吸土壤 PCBs 并进而增强 PCBs 降解可能具有重要意义。
