Photodegradation of polychlorinated dibenzo-p-dioxins in liquid samples by near UV light irradiation

被引:7
作者
Colombini, MP [1 ]
DiFrancesco, F [1 ]
Fuoco, R [1 ]
机构
[1] CNR,IST BIOFIS,I-56126 PISA,ITALY
关键词
D O I
10.1006/mchj.1996.0108
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
Photodegradation of 1,2,3,4-tetrachlorodibznzo-p-dioxin (1,2,3,4-TCDD) in hexane solution was studied under controlled near-UV light exposure in the spectral region from 325 to 269 nm. GC-MS was used to detect the amount of unreacted dioxin and to characterize the relevant degradation products. Irradiation experiments carried out at a constant light energy (700 mi) showed that the percentage of 1,2,3,4-TCDD left in the solution after irradiation changed from about 55 to 75%, with a minimum of 55% at 310 nm. Further irradiation experiments carried out at two wavelengths, namely 310 and 269 nm, and light energy ranging from 0 to 4000 mJ, showed that the photodegradation reaction of the TCDD always followed a pseudo-first-order kinetic, with a rate constant of 8 x 10(-4) and 5 x 10(-4) mJ(-1), respectively. These experiments also showed that trichloro- and dichloro-dibenzo-p-dioxins were produced with less than 15% of the initial quantity of TCDD, leading to the conclusion that the dechlorination process is a minor photolysis pathway. (C) 1996 Academic Press. Inc.
引用
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页码:331 / 337
页数:7
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