Catalytic performance and sulfur resistance of OMS-2 modified by copper for mercury removal at low temperature

• Cu dopant on OMS-2 greatly improves the surface area and active sites of catalyst. • Hg 0 removal efficiency of Cu 0.05 -OMS-2 is 92 % even in the presence of 1000 ppm SO 2 . • Cu-OMS-2 shows strong sulfur resistance for the protection of Cu on active sites. Cu-doped manganese oxide molecular sieve catalysts (Cu-OMS-2) are prepared by hydrothermal synthesis method, and their Hg 0 removal ability and sulfur resistance are investigated experimentally under simulated flue gas conditions. It indicated that appropriate proportion of Cu doped could increase both the content of Mn 4+ active sites on the catalyst surface and the BET specific surface area. The maximum specific surface area of these catalysts is 260.49 m 2 /g, with the Cu/Mn molar ratio of 0.025. A highest Hg 0 removal efficiency of 93.6 % is achieved by the catalyst with Cu/Mn molar ratio of 0.05. SO 2 in flue gas significantly inhibits the Hg 0 removal ability of OMS-2-H120, but its suppression ability is relatively weak after the addition of Cu to OMS-2-H120. The Hg 0 removal efficiency of Cu 0.05 -OMS-2 can reach 92 % even in the presence of 1000 ppm SO 2 . The doping of Cu on OMS-2 enhances SO 2 adsorbed by CuO, inhibiting the reaction of SO 2 with the active center on the catalyst surface. It reduces the generation of sulfate and enhances the sulfur resistance ability of Cu 0.05 -OMS-2. The process of Hg 0 oxidation by O 2 over Cu 0.05 -OMS-2 is found to follow Mars-Maessen mechanism based on the characteristics of fresh and spent catalysts. Elemental mercury is firstly chemisorbed on the Cu 0.05 -OMS-2 catalyst surface and then oxidized.