Investigation of La-doped MnOx in PTFE filter bag for low-temperature selective catalytic reduction of NOx in cement industry flue gas with NH3

With manganese acetate as a precursor, lanthanum (La) modified manganese oxide catalyst was prepared by coprecipitation method, and the catalyst prepared under optimized conditions was loaded on polytetrafluoroethylene (PTFE) filter bags with impregnation method. The results showed La/MnOx composite had excellent denitrification activity with La/Mn molar ratio was 0.10 and a calcination temperature was 400 °C. The NOx conversion rate reached 100% at 125 ∼ 300 °C when NO initial concentration was 500 ppm and gas hourly space velocity (GHSV) was 35,000 h − 1. And when the amount of PTFE binder was 8 g/L, catalyst loading was 220 g/m2 and the face velocity (FV) was 1.0 m/min, La (0.10)/MnOx (400) catalytic filter bag (CFB) reached about 90% NOx conversion efficiency at 200 °C and represented a good tolerance to H2O and SO2. La-modification facilitated manganese oxide in the form of amorphous α-Mn3O4, and the specific surface areas was enhanced. The increase of surface Mn4+ and adsorbed oxygen in the catalyst was conducive to the SCR reaction. In addition, the synergistic effect of La and Mn inhibited the formation of ammonium sulfate and enhanced the sulfur resistance.