Multipollutant removal of Hg0/SO2/NO from simulated coal-combustion flue gases using metal oxide/mesoporous SiO2 composites

This study investigated the multipollutant control effectiveness for Hg-0/SO2/NO using V, Mn, and Cu oxides/ mesoporous SiO2 particulate composites. The presence of metal oxides decreased the specific surface area and pore volume and altered the surface morphology and sizes of the raw SiO2 particles. V4+/V5+, Mn4+, and Cu+/Cu2+ were the major valence states in the VOx, MnOx, and CuOx/SiO2 composites, respectively. Amorphous and highly dispersed metal oxides presenting in the SiO2 composites was confirmed by the X-ray diffraction characteristic peaks. Multipollutant control of Hg-0 and NO using the metal oxide/SiO2 composites was achieved at both 150 and 350 degrees C under the simulated coal-combustion flue gas condition. CuOx/SiO2 with > 40% Hg-0 removal at 350 degrees C further implies that strong chemical bonds could form between Hg species and the surface groups of CuOx/SiO2. The metal oxide/SiO2 composites had up to 62% NO removal enhancement with injection of NH3 at 350 degrees C, indicating the effectiveness of catalytic reduction of NO. The CuOx/SiO2 composite showed the greatest Hg and NO removal performance, which may stem from the presence of active CuOx in high content and its large surface area and mesoporosity. (C) 2016 Published by Elsevier B.V.