Lin Yaw-Jian, Teng Li-Shan, Lee Ampere, Chen Yi-Ling
Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Nei Pu, Pingtung Hsien 91207, Taiwan.
Chemosphere. 2004 May;55(6):879-84. doi: 10.1016/j.chemosphere.2003.11.059.
The objective of this study was to investigate the effect of diethylamine and xenon simulated sunlight on the photodegradation of two forms of PCBs including PCBs in transformer oil and PCB congener 138. The result of GC chromatograms illustrated the shifting pattern of higher chlorinated biphenyls in transformer oil degraded to lower chlorinated biphenyls with the extension of exposure time. The effect of diethylamine and xenon simulated sunlight was significant on the photodegradation of both PCBs in transformer oil and congener 138. The initial degradation rates of congener 138 (1.14 x 10(-9) to 4.47 x 10(-9) mol l(-1) h(-1)) were in direct proportion to the initial concentrations of congener 138 which confirmed the pseudo-first-order reaction of PCB photodegradation. The apparent quantum yields (phi) of congener 138 using diethylamine in xenon photoreactor were ranged between 2.08 x 10(-2) and 9.8 x 10(-4). PCB congeners 123, 97, 70, 67, 33, 29, 17, 12, and 9 were detected as the descendants of the photodegradation of congener 138 through dechlorination. The major pathway of congener 138 photodegradation in this study was via para-dechlorination.
本研究的目的是调查二乙胺和氙模拟阳光对两种多氯联苯（PCBs）光降解的影响，这两种多氯联苯包括变压器油中的多氯联苯和多氯联苯同系物138。气相色谱图结果表明，随着暴露时间的延长，变压器油中高氯代联苯向低氯代联苯的转变模式。二乙胺和氙模拟阳光对变压器油中的多氯联苯和同系物138的光降解均有显著影响。同系物138的初始降解速率（1.14×10⁻⁹至4.47×10⁻⁹ mol l⁻¹ h⁻¹）与同系物138的初始浓度成正比，这证实了多氯联苯光降解的准一级反应。在氙光反应器中使用二乙胺时，同系物138的表观量子产率（φ）在2.08×10⁻²至9.8×10⁻⁴之间。通过脱氯检测到多氯联苯同系物123、97、70、67、33、29、17、12和9是同系物138光降解的产物。本研究中同系物138光降解的主要途径是对位脱氯。
