Removal of Hg0, NO, and SO2 by the surface dielectric barrier discharge coupled with Mn/Ce/Ti-based catalyst

In this study, power parameters (power, frequency, and voltage), initial Hg 0 concentration, and residence time are investigated for the removal of the increased Hg 0 concentration via surface dielectric barrier discharge (SDBD). The synergistic effect of a Mn/Ce/Ti catalyst with SDBD is verified with a mixture of flue gas (Hg 0 , NO, and SO 2 ). Results show that Hg 0 oxidation efficiency has an optimal frequency, which declines as the input voltage increases. The amplification of the Hg 0 removal efficiency decreases as voltage increases. The effect of the initial Hg 0 concentration gradually decreases as the peak voltage increases. The residence time slightly affects the Hg 0 removal efficiency at a high peak voltage. The cooling water temperature behaves differently on Hg 0 oxidation under high and low voltages. X-ray photoelectron spectroscopy (XPS) reveals the relative atomic concentrations of Mn 2+ and Mn 3+ in the Mn-TiO 2 and Mn-Ce-TiO 2 catalysts are 66.84% and 65.80%, respectively, which indicate that Ce addition will not affect surface Mn. Mn has a limited catalytic action on the removal of flue gas with and without SDBD. Nevertheless, SDBD can stimulate the oxygen storage capacity of Mn to increase the NO 2 conversion rate. Mn-Ce-TiO 2 greatly improves the removal efficiencies of NO and SO 2 because of the existence of the redox pairs of Mn 4+ /Mn 3+ , Ce 4+ /Ce 3+ , and Ti 4+ /Ti 3+ . However, the three catalysts slightly differ on Hg 0 removal when combined with SDBD, indicating that the effect of the catalyst was weakened after SDBD was added.