- Study of sorption, biodegradation and isomerization of HCH in stimulated sediment/water system
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This paper reported the sorption, biodegradation and isomerization of hexachlorocyclohexane (HCH) in laboratory sediment/water system under aerobic and anaerobic conditions, respectively. The effect of organic nutrient addition to the sorption of HCH was also investigated. It indicates that HCH is highly adsorbed on sediments under both conditions. During the tests, the biodegradation and isomerization of HCH were dramatically speeded up after organic nutrient additions, especially in the case of the observation under aerobic condition. It was found, β-HCH was the most persistent in the environment, that is due to the isomerization of α-HCH in a big amount to β-HCH, besides its chemical stability.
- Wu,Xu,Schramm,Kettrup
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p. 1887 - 1894
(2007/10/03)
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- Ultraviolet Light Induced Dechlorination of Vicinal Polychlorocyclohexanes with Triethylamine
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Photochemical dechlorination of trans- and cis-1,2-dichlorocyclohexanes (t-and c-DCC) in the presence of triethylamine (TEA) results in predominant dechlorination to form cyclohexene, where higher reactivity of the trans isomer over that of the cis (Φt-DCC/Φc-DCC = 4.8) is observed.Four stereoisomers of 1,2,3,4,5,6-hexachlorocyclohexanes, i.e., benzene hexaclorides (BHCs), were similarly dechlorinated to give their stereoselective benzene tetrachlorides (BTC), which mainly lose two adjacent chlorine atoms with a trans configuration to each other among the six chlorines available in BHC.Quantum efficiencies for the dechlorination of the four isomers α-, β-, γ-, and δ-BHC are 0.072, 0.060, 0.19, and 0,11, respectively, which correlate with their reduction potentials, implying that the reaction may be initiated by an electron transfer from TEA to BHC.
- Takagi, Katsuhiko,Ogata, Yoshiro
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p. 1966 - 1970
(2007/10/02)
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