State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, POPs Research Center, Tsinghua University, Beijing 100084, PR China.
J Hazard Mater. 2013 Sep 15;260:16-23. doi: 10.1016/j.jhazmat.2013.04.034. Epub 2013 Apr 30.
Photodegradation has been regarded as the main mechanism for the removal of many halogenated organic pollutants in the environment. The photodegradation of Dechlorane Plus (DP), an emerging contaminant taken worldwide concerns in recent years, was investigated under the irradiation of a xenon lamp. Rapid photodegradation was found under the irradiation of 200-750 nm light, while the degradation became much slower when the range of light wavelength changed to 280-750 nm. DP degradation followed the pseudo first-order kinetics. The quantum yields of 200-280 nm (UV-C) were about 2-3 orders of magnitude higher than 280-320 nm, and no yields can be detected in 320-750 nm range, in an agreement with the changing photodegradation rates with wavelength. The photodegradation products were identified as lower chlorinated DPs, implicating a mechanism of reductive dechlorination. No photoisomerization or solvent adducts were observed, and the difference of photodegradation rate between syn- and anti-DP isomers was negligible.
光降解被认为是环境中许多卤代有机污染物去除的主要机制。近年来，全球关注的新兴污染物 Dechlorane Plus（DP）的光降解在氙灯照射下进行了研究。在 200-750nm 光的照射下，发现 DP 迅速降解，而当光波长范围变为 280-750nm 时，降解速度变得很慢。DP 的降解符合准一级动力学。200-280nm（UV-C）的量子产率比 280-320nm 高 2-3 个数量级，而在 320-750nm 范围内则检测不到产率，这与随波长变化的光降解速率一致。光降解产物被鉴定为低氯代 DP，表明存在还原脱氯的机制。没有观察到光异构化或溶剂加合物，顺式和反式 DP 异构体的光降解速率差异可以忽略不计。
