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| Effect of fenton reagent on Hg0 re-emission in wet flue gas desulfurization system |
| Wang Jiang, Hang Chaodong, Zhang Yingjing, Chen Xue, Xu Jialing, Bao Jingjing |
State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower,
Sichuan University, Chengdu 610065, China |
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Abstract In order to inhibit the re-emission of Hg0 in the WFGD system and improve the mercury removal efficiency, the re-emission characteristics of Hg0 in the WFGD system based on the bubbler reactor were studied, and the inhibiting effect of Fenton reagent on the re-emission of Hg0 and its inhibiting mechanism were explored. The results show that the reduction of Hg2+ by SO32- and HSO3- in desulfurization solution is the main cause of Hg0 re-emission. H2O2 had a poor inhibiting effect on Hg0 re-emission, but the addition of H2O2 together with metal ions such as Fe3+, Fe2+ and Cu2+ can effectively inhibit the re-emission of Hg0, and inhibitory effect is Fe2+ > Fe3+ > Cu2+. The main reason of Fenton reagent inhibiting Hg0 re-emission is that oxidizing groups OH· and OOH· can oxidize Hg0 to Hg2+. When adding Fe2+-Fenton reagent: pH value of the desulfurization solution is in the range of 3.0 ~ 4.0, desulfurization liquid temperature is about 50 ℃, flue gas temperature is 120 ℃, the mercury removal efficiency of WFGD system is the best. Increasing the concentration of Fe2+ is conducive to improve the efficiency of mercury removal. However, when the concentration of Fe2+ is greater than 5×10-5, the efficiency of mercury removal is hardly influenced by the concentration of Fe2+.
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