Effects of flue gas components on the oxidation of gaseous Hg0 by dielectric barrier discharge plasma

•A dielectric discharge barrier reactor was developed for elemental mercury oxidation.•Active radicals generated in DBD reactor played important roles in Hg0 oxidation process.•O2, SO2 and HCl had positive effects on Hg0 oxidation.•NO inhibited Hg0 oxidation due to competing reaction for active radicals.

This study investigated the effects of gas components on the oxidation of Hg0 by dielectric barrier discharge (DBD) non-thermal plasma (NTP) technology. The findings indicated that reactive species such as O and Cl generated by ionization of O2 and HCl played dominant roles during oxidation processes. The presence of 50 ppm of HCl in N2/O2 atmosphere enhanced the Hg0 oxidation, the complete oxidation of Hg0 was observed by 6 kV of applied voltage. The presence of NO in the reactor decreased the Hg0 oxidation efficiency due to the interference by NO reaction with O and O3. The addition of 310 ppm of NO into the flue gas remained in 55% of Hg0 oxidation efficiency. Water vapor inhibited Hg0 oxidation, which was attributed to the consumption of reactive species and decomposition of HgOH. SO2 had a slight promoting effect on Hg0 oxidation, compared with the absence of SO2, the oxidation efficiency increased by 2–8% with the addition of 100–200 ppm of SO2. This study leads to starting the development of a novel promising environmental technology for Hg removal in the flue gas.