Outstanding performance of CuO/Fe-Ti spinel for Hg0 oxidation as a co-benefit of NO abatement: significant promotion of Hg0 oxidation by CuO loading

Conversion of gaseous Hg-0 to soluble Hg2+ using selective catalytic reduction (SCR) catalysts with gaseous HCl as an oxidant as a co-benefit of NO abatement is widely used for resolving Hg pollution from coal-burning power plants. Nevertheless, the performances of conventional V2O5-WO3/TiO2 for NO abatement and Hg-0 oxidation are unsatisfactory. In this study, CuO/Fe-Ti spinel was exploited as a novel and high-activity catalyst for the simultaneous removal of NO and Hg-0. The outstanding SCR activity and high N-2 selectivity of Fe-Ti spinel did not distinctly decrease after CuO loading; thus, CuO/Fe-Ti spinel achieved efficient NO reduction. Although Hg-0 physical adsorption onto Fe-Ti spinel was slightly suppressed after CuO loading, the Cl* radical formation was appreciably promoted as both HCl adsorption and the conversion of adsorbed Cl- to Cl* radicals were promoted. Hence, the Hg-0 oxidation activity of Fe-Ti spinel was appreciably improved after CuO loading, and the rate of Hg-0 oxidation for CuO/Fe-Ti spinel reached approximately 6.8-8.7 mu g g(-1) min(-1), which was better than those of most other SCR catalysts. In summary, CuO/Fe-Ti spinel shows great promise as an SCR catalyst for Hg-0 oxidation as a co-benefit of NO abatement from coal-burning flue gas (CFG).