Co and Mn co-impregnated ZSM-5 prepared from recycled industrial solid wastes for low-temperature NH3-SCR

A series of ZSM-5 catalysts were synthesized using fly ash from power plants and red mud from aluminum production in different weight ratios. The ZSM-5 was subsequently co-impregnated with Co and Mn, and tested for the low-temperature selective catalytic reduction of NOx by NH3 (NH3-SCR). 5wt.%Co10wt.%Mn/ZSM-5 had shown the best catalytic activity, with 98.8% conversion of NOx and 90.7% selectivity towards N2 at 150 °C. This is comparable to the performance of a similar ZSM-5 catalyst prepared using chemical reagents. The high ratio of Mn4+/(Mn4++Mn3++Mn2+) in the catalyst improved the NOx conversion, whereas the moderate redox property imparted by Co3+ led to high N2 selectivity. This catalyst also showed strong resistance against poisoning in 100 ppm SO2 and 5% H2O. This work demonstrates that porous the NH3-SCR catalyst produced from industrial solid wastes can be potentially applied in cement plants or incinerators.