Cubic SAPO-34 supported MnO for low-temperature gaseous mercury oxidation and adsorption from coal-fired flue gas

• Mn-based oxides were used for modification of SAPO-34. • The Hg 0 removal efficiencies were enhanced by adding Mn on SAPO-34. • Mn promoted the catalytic oxidation and chemical-adsorption processes. Gaseous elemental mercury (Hg 0 ) from industrial flue gas is difficult to be synergistically removed by existing flue gas purification equipment. In this paper, Mn-based oxides were used for the modification of SAPO-34 molecular sieve to enhance Hg 0 oxidation and adsorption performances. The results showed that when 5 % Mn dropped on the surface of SAPO-34, it had the highest Hg 0 removal efficiency and exhibited a better Hg 0 removal performance at lower temperature (<150 °C). SO 2 would compete for active adsorption sites of Hg 0 , while H 2 O vapor had little influence on Hg 0 removal. The Hg 0 removal mechanism was discussed based on experiment and characterization results and density functional theory calculation. The larger surface area and pore volume of Mn/SAPO-34 benefited the physical adsorption process. The surface MnO x particles enhanced the oxidation of Hg 0 to Hg 2+ and the oxygen site can further bond with Hg 2+ to form stable HgO. In addition, the larger desorption peak of HgO (487 °C) and the more negative adsorption energy (-1.21 eV) revealed the dominant role of chemical adsorption of Hg 0 over Mn/SAPO-34. Thus, the Mn/SAPO-34 is a potential catalyst for Hg 0 removal from industrial flue gas.