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

In this study, power parameters (power, frequency, and voltage), initial Hg concentration, and residence time are investigated for the removal of the increased Hg 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, NO, and SO). Results show that Hg oxidation efficiency has an optimal frequency, which declines as the input voltage increases. The amplification of the Hg removal efficiency decreases as voltage increases. The effect of the initial Hg concentration gradually decreases as the peak voltage increases. The residence time slightly affects the Hg removal efficiency at a high peak voltage. The cooling water temperature behaves differently on Hg oxidation under high and low voltages. X-ray photoelectron spectroscopy (XPS) reveals the relative atomic concentrations of Mn and Mn in the Mn-TiO and Mn-Ce-TiO 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 conversion rate. Mn-Ce-TiO greatly improves the removal efficiencies of NO and SO because of the existence of the redox pairs of Mn/Mn, Ce/Ce, and Ti/Ti. However, the three catalysts slightly differ on Hg removal when combined with SDBD, indicating that the effect of the catalyst was weakened after SDBD was added.