Experimental study on oxidation of elemental mercury by UV/Fenton system

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• 作者：Fuman Zhan ; Caiting Li ; Guangming Zeng ; Shasha Tao ; Yujun Xiao ; Xing Zhang ; Lingkui Zhao ; Jie Zhang ; Jinfeng Ma
• 关键词：Mercury ; Fenton&rsquo ; s reagent ; Free radicals ; WFGD
• 刊名：Chemical Engineering Journal
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：232
• 期：Complete
• 页码：81-88
• 全文大小：683 K

文摘

In order to implement Hg⁰ control strategy in a wet scrubber, oxidation of elemental mercury (Hg⁰) in the simulated coal-fired flue gas by UV/Fenton system was investigated. Effects of different operation parameters have been studied, including initial solution pH, H₂O₂, TiO₂ and Fe²⁺ concentration, solution temperature, gas flow rate and flue gas components (O₂, SO₂ and NO). The main ion products in the solution have been analyzed. The experimental results suggested that oxidation of Hg⁰ was inhibited with the increase of initial solution pH and gas flow rate. Additionally, with the increase of the H₂O₂, TiO₂, Fe²⁺ concentration and solution temperature, the Hg⁰ oxidation efficiency was enhanced to the maximum at first and then decreased. Hg⁰ oxidation can be significantly inhibited by SO₂ and NO when the flue gas was absence of O₂, but the oxidation capacity was recovered with 9 % O₂ exist in the flue gas. SO₂ showed an inhibition effect on Hg⁰ oxidation, while the inhibition was weakened at higher SO₂ concentration. Different NO concentration had an insignificant effect on Hg⁰ oxidation process under the experimental conditions. In the case of presence and absence of flue gas components (9 % O₂, 800 ppm SO₂, 600 ppm NO) and under the optimal conditions (pH = 1, [H₂O₂] = 0.05 mol/L; [TiO₂] = 0.6 g/L; [Fe²⁺]/[H₂O₂] = 1/2; T = 40 ¡ãC), the average oxidation efficiency of Hg⁰ can reach to 94.4 % and 98.5 % , respectively.