Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, Changchun 130118, China; Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China E-mail:
Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China E-mail:
Water Sci Technol. 2013;68(11):2479-84. doi: 10.2166/wst.2013.536.
The photochemistry of organic pollutants has received increasing attention in ice and snow. In this work, the photoconversion of gamma-hexachlorocyclohexane (γ-HCH) under UV irradiation was investigated in water, snow and ice. The photoconversion rate, products and mechanisms were inspected, and the effect of inorganic ions (NO2(-), NO3(-), HCO3(-) and Fe(2+)) was discussed. The results showed that γ-HCH could be photoconverted in water, snow and ice, with the photoconversion rate being fastest in snow, and slowest in ice. All photoconversion could be described by the first-order kinetics model. In water, snow and ice, the common photoproducts of γ-HCH were alpha-hexachlorocyclohexane (α-HCH) and pentachlorocyclohexene. α-HCH was generated by a change in the bonding of a chlorine atom in γ-HCH; pentachlorocyclohexene was generated by the removal of a molecule of chlorine hydride from a molecule of γ-HCH. Different concentrations of NO2(-), NO3(-) and HCO3(-) all inhibited the photoconversion of γ-HCH, and the inhibition effect decreased with increasing concentrations of NO2(-) and NO3(-), but increased with the increasing concentrations of HCO3(-). Different concentrations of Fe(2+) promoted the photoconversion of γ-HCH in water and ice, but had little effect in snow.
有机污染物的光化学已在冰雪中受到越来越多的关注。在这项工作中，研究了在水、雪和冰中，在紫外线照射下γ-六氯环己烷（γ-HCH）的光转化。检验了光转化速率、产物和机制，并讨论了无机离子（NO2(-)、NO3(-)、HCO3(-)和 Fe(2+)）的影响。结果表明，γ-HCH 可在水、雪和冰中光转化，在雪中的光转化速率最快，在冰中最慢。所有的光转化都可以用一级动力学模型来描述。在水、雪和冰中，γ-HCH 的常见光产物为α-六氯环己烷（α-HCH）和五氯环己烯。α-HCH 是通过 γ-HCH 中一个氯原子的键合变化生成的；五氯环己烯是通过从 γ-HCH 分子中去除一个氯氢分子生成的。不同浓度的 NO2(-)、NO3(-) 和 HCO3(-)都抑制了 γ-HCH 的光转化，抑制效果随着 NO2(-)和 NO3(-)浓度的增加而降低，但随着 HCO3(-)浓度的增加而增加。不同浓度的 Fe(2+)促进了水和冰中 γ-HCH 的光转化，但在雪中影响不大。
