Polarity effect of pulsed corona discharge for the oxidation of gaseous elemental mercury

► Polarity effect of a pulsed corona discharge (PCD) for Hg 0 oxidation. ► No difference in the energy yield of Hg 0 oxidation at both polarities. ► Positive PCD process playing essential key role in Hg 0 oxidation. ► Electrical precipitator (EP) consuming less energy than positive PCD. ► EP not playing essential key role in Hg 0 oxidation. The effect of polarity on the oxidation of Hg 0 was examined in the presence of O 2 via a pulsed corona discharge (PCD). The experimental result showed no difference in the energy yield of Hg 0 oxidation at both positive and negative PCDs (∼8 μg Hg W h −1 at following conditions: total flow rate = 2 L min −1 (Hg 0 = 50 μg N m −3, O 2 = 10%, and N 2 balance), temperature = 150 °C, and specific energy density = 5–15 W h N m −3). This suggests that the positive PCD process used to control gaseous air pollutants may play an essential key role in Hg 0 oxidation because it consumes enough energy (∼15 W h N m −3) but an electrical precipitator could not because it consumes less energy (∼0.3 W h N m −3) to oxidize Hg 0.