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

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 SO2 in the flue gas significantly restrained the Hg-0 adsorption and oxidation over 6%Ce-6%MnOx/Ti-PILC due to the formation of SO42- species. Hg-0 could be oxidized to HgCl2 in the presence of HCl, because the Deacon process occurred. NO would react with active oxygen to form NO2-containing species, which facilitated Hg-0 oxidation. While the presence of NO limited the Hg-0 adsorption on 6%Ce-6%MnOx/Ti-PILC due to the competitive adsorption of NO with Hg-0. The addition of NH3 in the flue gas significantly restrained Hg-0 adsorption and oxidation, because the formed NH4+ species covered the active adsorption sites on the surfaces, and further limited Hg-0 oxidation. However, when NO and NH3 were simultaneously added into the flue gas, the Hg-0 oxidation efficiency of 6%Ce-6%MnOx/Ti-PILC exhibited a relatively high value (72%) at 250 degrees C, which indicated the practicability to use Ce-MnOx/Ti-PILC for Hg-0 removal under SCR conditions. (C) 2015 Elsevier B.V. All rights reserved.