Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
580804 | Journal of Hazardous Materials | 2009 | 5 Pages |
Abstract
In this study, considering that Hg2+ in wet flue gas desulfurization (FGD) systems can easily be reduced and then released into atmosphere, causing secondary pollution, the researches about Hg2+ reduction and Hg0 re-emission mechanism were carried out. The effects of several experimental parameters on the reduction were studied, including initial pH, temperature, and concentrations of Clâ and S(IV). Our experimental results indicated that Clâ had a restraining effect on the Hg2+ reduction and Hg0 re-emission, after 24 h reaction, only 20.5% of Hg2+ was reduced with 100 mM Clâ in simulated desulfurization solution. Clâ can slow Hg2+ reduction and Hg0 re-emissions dramatically through changing reaction mechanism, with formation of new intermediate: ClHgSO3â, which can decompose to Hg0, but much more slowly than Hg(SO3)22â or HgSO3. Simulating the conditions of the practical application (initial pH 5, T = 50 °C, S(IV) = 5 mM, Clâ = 100 mM), we also found that Ca2+, NO3â, Fâ, etc. all had obvious effects on reduction rates. Based on the material balance and characteristic of the reactants, the reduction emission mechanism of Hg2+ has been established, providing theoretical basis for industrial application of mercury control in wet FGD systems.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Health and Safety
Authors
Jingjing Wo, Meng Zhang, Xiaoya Cheng, Xiaohang Zhong, Jiang Xu, Xinhua Xu,