Simultaneous purifying of Hg0, SO2, and NOx from flue gas by Fe3+/H2O2: the performance and purifying mechanism.

Hg0, SO2, and NOx result in heavily global environmental pollution and serious health hazards. Up to now, how to efficiently remove mercury with SO2 and NOx from flue gas is still a tough task. In this study, series of high oxidizing Fenton systems were employed to purify the pollutants. The experimental results showed that Fe3+/H2O2 was more suitable to purify Hg0 than Fe2+/H2O2 and Cu2+/H2O2. The optimal condition includes Fe3+ concentration of 0.008 mol/L, Hg0 inlet concentration of 40 μg/m3, solution temperature of 50 °C, pH of 3, H2O2 concentration of 0.7 mol/L, and O2 percentage of 6%. When SO2 and NOx were taken into account under the optimal condition, Hg0 removal efficiency could be enhanced to 91.11% while the removal efficiency of both NOx and SO2 was slightly declined, which was consistent to the analysis of purifying mechanism. The removal efficiency of Hg0 was stimulated by accelerating the conversion of Fe2+ to Fe3+, which resulted from the existence of SO2 and NOx. The results of this study suggested that simultaneously purifying Hg0, SO2, and NOx from flue gas is feasible.