Simultaneous Removal of Elemental Mercury and NO from Simulated Flue Gas at Low Temperatures over Mn-V-W/TiO2 Catalysts

A series of Mn-V-W/TiO2 (Mn-VWT) catalysts were synthesized by the impregnation method and calcinated at different temperatures (300-600 degrees C). To explore the effects of the reaction temperature, SO2, and H2O on the simultaneous removal performance of elemental mercury (Hg-0) and NO, Mn-VWT were investigated by a fixed-bed reaction system. Various techniques (scanning electron microscopy, Brunauer Emmett Teller, X-ray diffraction, H-2-temperature-programmed reduction, NH3-temperature-programmed desorption, and X-ray photoelectron spectroscopy) were utilized to characterize the samples. The results showed that the catalytic activity of Mn-VWT first increased and then decreased with the increasing calcination temperature. The removal efficiency of Hg-0 and NO still had good performance even in low reaction temperature (200 degrees C), achieving 100 and 82%, respectively. Mn-VWT-400 had the best simultaneous removal performance because of the highest content of the Mn4+, V4+, and chemisorbed oxygen O-alpha and the best reductive activity at low temperature. Furthermore, SO2 irreversibly inhibited Hg-0 and NO removal ability due to the sulfate and sulfite generation on the surface of Mn-VWT-400. Especially, the inhibition effect was more serious if SO2 and H2O coexisted because the rate of sulfate/sulfite was higher than that of the former. In addition, with the increase in reaction temperature, the effect of SO2 and H2O on the removal of Hg-0 and NO over Mn-VWT was gradually reduced.