Using CuO-MnO_x/AC-H as catalyst for simultaneous removal of Hg° and NO from coal-fired flue gas

A series of CuO-MnO_x modified catalysts were prepared, and proposed for simultaneous removal of Hg° and NO from flue gas. As Mn loading value was 5%, the high value of 90% Hg and 60% NO_x were removed efficiently. With gradual increasing of reaction temperature, the mercury removal efficiency (Mercury RE) first increased to 92% then decreased slightly, while NO_x removal efficiency (NO_x RE) exhibited a trend of continuous increase. O₂ had promotional effect on the double pollutants removal, while NH₃ had slightly negative effect on Hg° removal. As 5% O₂ was added into system, the removal efficiency of Hg and NO_x rose by 30% and 47%, respectively. Unfortunately, Mercury RE decreased to 90% in the presence of 500 ppm NH₃. Overall, superior Mercury RE (>90%) and NO_x RE (78%) were performed over 8%CuO-5%MnO_x/AC-H at 200 °C. XRD results revealed calcination affected catalysts activity by playing a role in active components formation at different temperature. In XPS spectra, new formation of HgO and Hg° adsorption on spent catalysts revealed the possible reaction processes that the conversion of CuO and MnO₂ on fresh catalyst to other species benefited HgO formation. The removal mechanism might be a combination of Langmuir-Hinshelwood and Mars-van-Krevelen mechanism.