MnOx/TiO2 catalysts/sorbents were investigated for flue gas purification via the simultaneous low-temperature NH3-SCR of NO and elemental Hg capture, in the temperature range 25-300°C. In particular, the effects of the Mn precursor salt (acetate vs. nitrate) and of the TiO2 support textural properties (nanotubes vs. random mesopores) on both DeNOx and Hg capture efficiencies were addressed. The catalysts/sorbents were also characterized by means of ICP-MS, SEM-EDX, XRD, BET, H2-TPR, NH3 adsorption, and temperature programmed desorption of both NH3 and Hg. Catalysts prepared by acetate precursor generally displayed a higher reducibility at low temperature which translated into a higher oxidation activity, enhancing mercury capture rate, but adversely affecting the selectivity of the selective catalytic reduction (SCR) process at temperatures above 150°C. Hg was effectively captured up to 250°C and stored on the sorbent in an oxidized form. The original sorption properties could be fully restored by a simple thermal treatment in air at temperatures <=500°C, releasing elemental mercury. The textural properties of the support were found to have a limited impact on both the Hg capture and SCR performance
Combined mercury removal and low-temperature NH3 -SCR OF NO with MnOx /TiO2 sorbents/catalysts
Cimino S;
2018
Abstract
MnOx/TiO2 catalysts/sorbents were investigated for flue gas purification via the simultaneous low-temperature NH3-SCR of NO and elemental Hg capture, in the temperature range 25-300°C. In particular, the effects of the Mn precursor salt (acetate vs. nitrate) and of the TiO2 support textural properties (nanotubes vs. random mesopores) on both DeNOx and Hg capture efficiencies were addressed. The catalysts/sorbents were also characterized by means of ICP-MS, SEM-EDX, XRD, BET, H2-TPR, NH3 adsorption, and temperature programmed desorption of both NH3 and Hg. Catalysts prepared by acetate precursor generally displayed a higher reducibility at low temperature which translated into a higher oxidation activity, enhancing mercury capture rate, but adversely affecting the selectivity of the selective catalytic reduction (SCR) process at temperatures above 150°C. Hg was effectively captured up to 250°C and stored on the sorbent in an oxidized form. The original sorption properties could be fully restored by a simple thermal treatment in air at temperatures <=500°C, releasing elemental mercury. The textural properties of the support were found to have a limited impact on both the Hg capture and SCR performanceI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
