Effects of flue gas components on removal of elemental mercury over Ce-MnOx/Ti-PILCs.

Abstract The adsorption and oxidation of elemental mercury (Hg 0 ) under various flue gas components were investigated over a series of Ce–MnO x /Ti-PILC catalysts, which were synthesized by an impregnation method. To discuss the mechanism, the catalysts were characterized by various techniques such as N 2 adsorption–desorption, scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) analysis and X-ray photoelectron spectroscopy (XPS). The results indicated that the presence of 500 ppm SO 2 in the flue gas significantly restrained the Hg 0 adsorption and oxidation over 6%Ce–6%MnO x /Ti-PILC due to the formation of SO 4 2− species. Hg 0 could be oxidized to HgCl 2 in the presence of HCl, because the Deacon process occurred. NO would react with active oxygen to form NO 2 -containing species, which facilitated Hg 0 oxidation. While the presence of NO limited the Hg 0 adsorption on 6%Ce–6%MnO x /Ti-PILC due to the competitive adsorption of NO with Hg 0 . The addition of NH 3 in the flue gas significantly restrained Hg 0 adsorption and oxidation, because the formed NH 4 + species covered the active adsorption sites on the surfaces, and further limited Hg 0 oxidation. However, when NO and NH 3 were simultaneously added into the flue gas, the Hg 0 oxidation efficiency of 6%Ce–6%MnO x /Ti-PILC exhibited a relatively high value (72%) at 250 °C, which indicated the practicability to use Ce–MnO x /Ti-PILC for Hg 0 removal under SCR conditions.