Study of mercury re-emission in a simulated WFGD solution containing thiocyanate and sulfide ions

Wang, Qingfeng; Liu, Yue; Zhen-mei, Yang; Wang, Haiqiang; Weng, Xiaole; Wang, Yuejun; Wu, Zhongbiao

doi:10.1016/j.fuel.2014.05.080

Cited by 16 publications

(10 citation statements)

References 34 publications

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“…Up to now, most of the research on DGM production was under laboratory or natural water conditions. In wastewater containing mercury, only the reemission process of mercury in a simulated wet flue gas desulfurization (WFGD) solution (Wang et al 2014) and seawater flue gas desulfurization (SWFGD) system (Sun et al 2013) was reported.…”

Section: Introductionmentioning

confidence: 99%

Effect on the Photo-production of Dissolved Gaseous Mercury in Post-desulfurized Seawater Discharged from a Coal-Fired Power Plant

Sun

Yuan

et al. 2015

Water Air Soil Pollut

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A high concentration of dissolved gaseous mercury (DGM) was detected in post-desulfurized waste seawater, which was discharged from a coal-fired power plant equipped with a seawater desulfurization system and which was located in a coastal area. A large amount of DGM was converted from other forms of mercury during transformation processes, such as photo-reduction. The present study targeted the photo-reduction of mercury and the effects of various environmental parameters on DGM production in the post-desulfurized seawater discharged. The results suggested that the photoreduction of mercury was significantly induced under UV radiation, especially with UVB. The particulate mercury on suspended solids was easily photo-reduced and considered as an important source of DGM. It was confirmed that the suspended solids in postdesulfurized seawater could enhance the reduction process of mercury under UV radiation. The pseudo-firstorder rate constants of DGM production, which were determined through the concentration gradient and trial methods, were 1.39×10 −3 min −1 and 1.45×10 −3 min −1 , respectively. The values showed no significant difference and were both much higher than the reported results, indicating that the photo-reduction of mercury in post-desulfurized seawater deserved more attention. In addition, the initial mercury level was observed when mixing the post-desulfurized seawater with fresh seawater, and this suggested that a significant amount of initial mercury would be produced when the post-desulfurized seawater was discharged into the adjacent sea area and thus becomes another considerable source of DGM.

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Section: Introductionmentioning

confidence: 99%

Effect on the Photo-production of Dissolved Gaseous Mercury in Post-desulfurized Seawater Discharged from a Coal-Fired Power Plant

Sun

Yuan

et al. 2015

Water Air Soil Pollut

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“…When the arsenite ions in solution were free (Figure 9a), the peak was at 236 nm and was identified as Hg(SO 3 ) 2 2− , which was consistent with previous literature. 18,34 The peak intensity at 236 nm gradually decreased from 1.9 to 0.3 within 20 min due to the decomposition of Hg(SO 3 ) 2 2− . With the increase in arsenite concentration, the peaks moved from 236 to 230 nm with a rapid decay rate of peak intensity.…”

Section: Energy and Fuelsmentioning

confidence: 99%

Mercury Re-Emission in the Smelting Flue Gas Cleaning Process: The Influence of Arsenite

et al. 2017

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Recently, the Hg0 re-emission from flue scrubbing solutions has become a research focus. The objective of this study was to evaluate the influence of arsenite on Hg0 re-emission by investigating critical important parameters, including the arsenite ion concentration, pH values, solution temperature, fluorine ion concentration, and chlorine ion concentration. The experimental results indicate that arsenite could directly reduce Hg2+ to Hg0 and promote the decomposition of Hg(SO3)2 2–. High pH, temperature, and chlorine ion concentration contributed to the inhibition of Hg0 re-emission, but the fluorine ions had little effect. The mechanism research suggests that the formation of unstable HgH2AsO3 + at low arsenite concentration accelerates Hg0 re-emission. For the Hg(II)–As(III)–S(VI) system, the formation of unstable HgSO3H2AsO3 – than Hg(SO3)2 2– could increase Hg0 re-emission. With an increase in arsenite concentration, the formation of Hg(H2AsO3)2 (which comes from the reaction between HgSO3H2AsO3 – and H2AsO3 –) contributes to the suppression of Hg0 re-emission. The results of this study are conducive to providing new insight into Hg0 re-emission and mercury control.

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“…Promotion of Hg 0 oxidation by adding chemical additives is an effective way to improve stability of Hg 2+ and removal of Hg 0 in a WFGD system. In previous works, the most used additives included oxidizing additives and precipitating/chelating additives. − Because of its strong oxidizability, simple process, and no secondary pollution, Fenton reagent has attracted broad attention in inhibition of Hg 0 re-emission. Lu et al reported that Fenton reagent exhibited an excellent promotive effect on Hg 0 oxidization, mainly as a result of the hydroxyl free radicals (•OH) with strong oxidizing property in desulfurization slurry.…”

Section: Introductionmentioning

confidence: 99%

“…Different from oxidizing additives, precipitating/chelating additives can capture and stabilize Hg 2+ in the liquid phase by generating precipitations or chelates, which are easy to be separated from slurry. Wang et al 29 found that hydrogen sulfide ions in desulfurization solution were able to suppress reduction of Hg 2+ efficiently, owing to the formation of HgS precipitate. Its inhibition effect on Hg 0 re-emission under alkaline conditions is much better than that under acidic conditions.…”

Section: Introductionmentioning

confidence: 99%

Characteristics and Inhibition of Hg⁰ Re-emission in a Wet Flue Gas Desulfurization System

Bao

Tang

et al. 2018

Energy Fuels

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Characteristics of Hg 0 re-emission in a wet flue gas desulfurization (WFGD) system were investigated on the basis of a bubble column. Five addition agents were used to inhibit Hg 0 re-emission and improve removal of gaseous mercury. The results show that SO 3 2− plays an important role in Hg 0 re-emission in a WFGD system. Hg 0 re-emission is intensified sharply in the presence of SO 3 2− and further intensified with the increase of the SO 3 2− concentration. Hg 0 re-emission is strengthened at a higher temperature of desulfurization slurry. However, the removal efficiencies of both Hg 2+ and total gaseous mercury decrease significantly with an increasing slurry temperature. The decreasing amplitude of total mercury removal efficiency is slightly higher than that of Hg 2+ . In addition, the re-emission rate of Hg 0 declines first and then increases with an increasing pH value. A least Hg 0 re-emission is observed at a pH value of 5.5. Fenton reagent, NaClO, K 2 S 2 O 8 , Na 2 S, and ethylenediaminetetraacetic acid (EDTA) can inhibit Hg 0 re-emission to different extents. Among them, Fenton reagent and EDTA exhibit better performance than that of NaClO and Na 2 S. The least inhibition effect is found for K 2 S 2 O 8 . For the sake of effective inhibition of Hg 0 reemission and gaseous mercury removal, a lower slurry temperature, a pH value in the range of 2.5−3.5, and a Fe 2+ concentration of 50 mg/L are optimal in a practical WFGD system.

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Study of mercury re-emission in a simulated WFGD solution containing thiocyanate and sulfide ions

Cited by 16 publications

References 34 publications

Effect on the Photo-production of Dissolved Gaseous Mercury in Post-desulfurized Seawater Discharged from a Coal-Fired Power Plant

Effect on the Photo-production of Dissolved Gaseous Mercury in Post-desulfurized Seawater Discharged from a Coal-Fired Power Plant

Mercury Re-Emission in the Smelting Flue Gas Cleaning Process: The Influence of Arsenite

Characteristics and Inhibition of Hg⁰ Re-emission in a Wet Flue Gas Desulfurization System

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Study of mercury re-emission in a simulated WFGD solution containing thiocyanate and sulfide ions

Cited by 16 publications

References 34 publications

Effect on the Photo-production of Dissolved Gaseous Mercury in Post-desulfurized Seawater Discharged from a Coal-Fired Power Plant

Effect on the Photo-production of Dissolved Gaseous Mercury in Post-desulfurized Seawater Discharged from a Coal-Fired Power Plant

Mercury Re-Emission in the Smelting Flue Gas Cleaning Process: The Influence of Arsenite

Characteristics and Inhibition of Hg0 Re-emission in a Wet Flue Gas Desulfurization System

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Characteristics and Inhibition of Hg⁰ Re-emission in a Wet Flue Gas Desulfurization System