Electrochemical enhancement of high-efficiency wet removal of mercury from flue gas

Xu, Nai-jiao; Li, Sen; Fu, Yu-hong; Wang, Zhao-yang; Feng, Li-juan; Wang, Ji

Electrochemical enhancement of high-efficiency wet removal of mercury from flue gas

2022

Electrochemical wet absorption composite system has an excellent potential to remove Hg⁰ from flue gas. In this study, ruthenium iridium titanium platinum quaternary composite electrode is used as an anode and titanium electrode is used as the cathode, and KI/I₂ absorption solution is introduced into the electrocatalysis system as an electrolyte to form KI/I₂ electrochemical catalytic oxidation system. The removal rate of Hg⁰ in flue gas can be increased to 92.3%. The effects of electrolytic voltage, current, Pt content, I₂ concentration, and the ratio of KI/I₂ on the removal of Hg⁰ were discussed. The possible free radicals in the electrochemical cathode, anode, and solution were characterized and tested by XRD, SEM, UV-Vis (detection of H₂O₂, ·OH, O₃), and FTIR (detection of IO₃⁻). Combined with experimental data and theoretical derivation, the mechanism of Hg⁰ removal from flue gas by electrochemical catalytic oxidation alloy formation wet absorption combined process was studied. The results show that the combined process, which is a promising technology can not only improve the removal efficiency of Hg⁰, but also realize the resource recovery of Hg⁰ and I₂, and provide a feasibility study for the subsequent regeneration of KI/I₂ absorption solution.

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