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

Abstract

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.