Simultaneous Removal of Elemental Mercury and NO from Flue Gas Using CeO2 Modified MnOx/TiO2 Materials

The laboratory-scale simultaneous removal of elemental mercury (Hg-0) and NO has been investigated using MnOx/TiO2, MnOx/CeO2-TiO2, and CeO2-TiO2 materials in the presence and absence of CO. Remarkably, these materials exhibit excellent NO removal performance and high Hg-0 adsorption capacities both in single-component (NO or Hg-0) tests and in combined NO and Hg-0 removal experiments at 175 degrees C. Interestingly, NO removal increased in the presence of CO due to the selective catalytic reduction (SCR) by CO over 20% MnOx/CeO2-TiO2; Hg-0 adsorption did not inhibit SCR activity. In simultaneous removal tests, 20 wt % MnOx/CeO2-TiO2 effectively removed 9.4 mg Hg-0 g(-1) and 358 mg NO g(-1) at 175 degrees C. The surface areas of the TiO2 and CeO2-TiO2 materials decreased after impregnation with MnOx. CeO2-based materials have more lattice oxygen defects than TiO2, thus enhancing SCR in the presence of CO. Adsorbed Hg-0 reacts with lattice oxygen to form HgO on the surface of the CeO2-based materials.