Deng Lin, Fu Dafang, Deng Nansheng
Department of Municipal Engineering, Southeast University, Nanjing, China.
J Hazard Mater. 2009 May 30;164(2-3):798-805. doi: 10.1016/j.jhazmat.2008.08.087. Epub 2008 Aug 30.
The effects of algae (i.e., Chlorella vulgaris), Fe(III), humic substances, and pH on the photoreduction of Hg(II) under the irradiation of metal halide lamps (lambda>or=365 nm, 250 W) were investigated in this paper. The photoreduction rate of Hg(II) was found to increase with the increasing concentration of algae, Fe(III), and humic substances. The cooperation action of Fe(III) and humic substances accelerated the photoreduction of Hg(II). When the initial concentration of Hg(II) was in the range of 0.0-200.0 microg L(-1) with initial algae concentrations 7.0 x 10(9)cells L(-1) at pH 7.0, the initial photoreduction rate of Hg(II) could be expressed by the equation: -dC(Hg(II))/dt=0.65 x C(Hg(II)) with a correlation coefficient of R=0.9912. The study on the photochemical process in terms of total mercury mass balance revealed that more than 40.86% of Hg(II) from the algal suspension was reduced to volatile metallic mercury. This paper discussed the photoreduction mechanism of Hg(II) in the presence of algae. This research will provide information for predicting the photoreduction of Hg(II) in the real environment. It will be helpful for understanding the photochemical transformation of Hg(II) and the formation of DGM in natural water in the presence of algae complexes. It will also be helpful for providing new methods to deal with heavy metal pollution.
本文研究了藻类（即普通小球藻）、铁（III）、腐殖质和pH值对金属卤化物灯（波长≥365nm，250W）照射下汞（II）光还原的影响。发现汞（II）的光还原速率随藻类、铁（III）和腐殖质浓度的增加而增加。铁（III）和腐殖质的协同作用加速了汞（II）的光还原。当汞（II）的初始浓度在0.0 - 200.0μg L⁻¹范围内，初始藻类浓度为7.0×10⁹个细胞L⁻¹，pH值为7.0时，汞（II）的初始光还原速率可用方程表示：-dC(汞（II）)/dt = 0.65×[C(汞（II）)]⁰·³⁹，相关系数R = 0.9912。从总汞质量平衡角度对光化学过程的研究表明，藻类悬浮液中超过40.86%的汞（II）被还原为挥发性金属汞。本文讨论了藻类存在下汞（II）的光还原机理。该研究将为预测实际环境中汞（II）的光还原提供信息。有助于理解藻类存在时天然水中汞（II）的光化学转化以及溶解气态汞的形成。也有助于提供处理重金属污染的新方法。
