Simultaneous removal of SO2, NO and Hg0 from flue gas by ferrate (VI) solution

• Prepared ferrate (VI) absorbent has excellent property of removing SO2, NO and Hg0.
• 100% of SO2, 63.8% of NO and 83.6% of Hg0 were simultaneously removed.
• The simultaneous removal mechanism of SO2, NO and Hg0 was proposed.

Simultaneously removing SO2, NO and Hg0 from flue gas was examined by ferrate (VI) solution at a bubbling reactor. The removal efficiencies of 100% for SO2, 64.8% for NO and 81.4% for Hg0 were achieved respectively, under the optimum experimental conditions, in which concentration of ferrate (VI) solution was 0.25 mmol/L, solution pH was 8.0, flue gas flow rate was 1 L/min and reaction temperature was 320 K. Based on the discussions of the ferrate (VI) solution characteristics, the comparisons of the standard electrode potential (E0) of ferrate (VI) solution with E0 values of reactant, and the analysis of the reaction products, a mechanism of simultaneous removal was proposed. In the process of simultaneous removal, FeO42− and HFeO4− as the dominant species of ferrate (VI), could rapidly oxidize SO2, NO, and Hg0 into SO42−, NO3− and Hg2+.