A surface dielectric barrier discharge plasma reactor was employed to study Hg 0 oxidation in coal-fired flue gas. The experimental results showed that 98 % of Hg 0 oxidation efficiency and 13.7 lg kJ -1 of energy yield were obtained under a specific energy density (SED) of 7.9 J L -1 . Increasing SED was beneficial for Hg 0 oxidation due to higher production of active species. Higher initial concentration resulted in lower Hg 0 oxidation efficiency, but higher amount of Hg 0 oxidation. Water vapor inhibited Hg 0 oxidation because the generation of O 3 was suppressed. The presence of NO remarkably restrained Hg 0 oxidation, while SO 2 showed little effect on Hg 0 oxidation. Roles of active species in Hg 0 oxidation were examined under different gas atmospheres (O 2 and air), indicating that O 3 played an important role in Hg 0 oxidation. Deposits on the internal surface of the reactor were analyzed by energy dispersive spectroscopy and the product was identified as HgO.

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Oxidation of gas phase elemental mercury (Hg0) in the simulated flue gas by DBD plasma under atmospheric pressure and ambient temperature (298 K) was conducted. Experimental results indicated that the oxidative efficiency of Hg0 increased with O2 content, the residence time of flue gas in reactor and the applied voltage. The oxidation efficiency of Hg0 reached over 96% under the applied voltage of 11 kV and the residence time of 0.24 s when the O2 content in flue gas was 20%, and the corresponding energy efficiency was at about 14.1 μg kJ-1. It was noted that the oxidation efficiency of Hg0 could still reach 80% when the O2 content in flue gas was only 4% (near the actual O2 content in flue gas of coal-fired boilers). The experimental results indicated that DBD plasma was one of the efficient technologies for purification of Hg0 vapor industrial flue gas.

The removal of elemental mercury (Hg0) with the reactive species produced by gas phase surface discharge plasma was studied. The effects of several operational parameters, such as applied voltage, inlet Hg0concentration and gas humidity, were investigated. The removal of Hg0was significantly promoted by an increase in the applied voltage of the reactor system. Hg0oxidation efficiency decreases with increasing inlet Hg0concentration. Furthermore, with the addition of H2O, Hg0oxidation is remarkably restrained.