In-situ catalytic oxidation of Hg0 via a gas diffusion electrode

A diffusion electrochemical reactor was proposed to remove elemental mercury (Hg 0 ) from coal-fired flue gas. The experiments were carried out in an undivided column reactor with a self-made gas diffusion electrode (GDE) as cathode and Ti/IrO 2 as anode. Hg 0 was oxidized when the simulated gas passed through GDE. It turned out that the removal of Hg 0 in electrochemical process was dominated by electro-generated H 2 O 2 and free radicals on GDE interface or in the electrolyte. Under 70   °C, Hg 0 removal efficiency exceeded 90% after 40   min electrolysis. The effects of operation parameters were investigated and the results demonstrated that voltage, gas flow rate, and initial concentration of Hg 0 had significant influences on Hg 0 removal, especially the reaction temperature, electrolyte concentration and pH. H 2 O 2 and HO in the electrolyte were measured by UV–vis spectrophotometer and electron spin resonance (ESR), respectively. The above results show that electrochemical technique is a promising method for emission control of Hg 0 from coal-fired flue gas.