4Cu-ZSM-5 catalyst for the selective catalytic reduction of NO with NH3 and oxidation of elemental mercury

Abstract

4Cu-ZSM-5 catalyst was synthesized using microwave wet impregnation for simultaneous removal of NO and elemental mercury (Hg0) from simulated flue gas. The highest removal efficiencies were achieved at 250 C for both NO (96.5%) and Hg0 (84.5%). Meantime, the effect of O2, NH3 and SO2 were investigated. The results showed that 5% O2 and 500 ppm NH3 made the removal efficiencies be the highest and after the addition of 100 ppm SO2, the removal efficiencies reduced to 40% for NO and 55% for Hg0. According to the characterization results, 4Cu-ZSM-5 had better thermal stability abundant reducing substances and richer weak acid sites for the simultaneous removal of NO and Hg0. NO formed bridging nitrates on the 4Cu-ZSM-5 surface and then combined with NH3 to form Lewis acid sites for reducing to N2. Meanwhile, Cu2+ induced Hg0 to give electrons, making it oxidized to HgO.