Simultaneous removal of elemental mercury and NO in simulated flue gas over V2O5/ZrO2-CeO2 catalyst.

A series of V/ZrCe x catalyst synthesized by a co-precipitation method was employed to investigate the simultaneous removal of NO and elemental mercury (Hg 0 ) in simulated flue gas. The catalysts were characterized using BET, SEM, XRD, H 2 –TPR, XPS, and FT–IR. V/ZrCe 0.6 with CeO 2 /ZrO 2 molar ratio of 0.6 showed excellent SCR activity (87.3%) and high Hg 0 oxidation efficiency (77.6%) in SCR atmosphere (NH 3 /NO = 1). The results indicated that the Hg 0 had little impact on NO conversion, while the coexistence of NO and O 2 would be beneficial for the Hg 0 oxidation. Hg 0 oxidation was inhibited in SCR atmosphere owing to the presence of NH 3 . The characterization results demonstrated that the superior performance of V/ZrCe 0.6 catalyst might be attributed to lower crystallinity, better texture properties, strong redox ability and high reactive nitrate together with NH 3 species. The redox equilibrium (Ce 3+ + V 5+ ↔ Ce 4+ + V 4+ ) contributed to the NO conversion and Hg 0 oxidation. The bidentate sulfates formed by adsorbed SO 2 could provide new acid sites for NH 3 adsorption and increase the amount of NH 4 + , which reduced the poisoning effect of SO 2 and H 2 O. Based on the experimental results, a mechanism for the simultaneous removal of NO and Hg 0 was proposed for the V/ZrCe 0.6 catalysts: 2NH 3 /NH 4 + (ad) + NO 2 (ad) + NO(g) → 2N 2 + 3H 2 O + /2H + , Hg(ad) + Oβ → HgO(ad). [ABSTRACT FROM AUTHOR]