Removal of NO with the hexamminecobalt solution catalyzed by the carbon treated with oxalic acid

Abstract

NO can be removed at the same time with SO₂ by aqueous Co(NH₃)₆²⁺ solution. The reduction of Co(NH₃)₆³⁺ to Co(NH₃)₆²⁺ is catalyzed by activated carbon to regain the NO absorption ability of the scrubbing solution. Oxalic acid solution is explored to change the carbon surface to ameliorate its catalytic capability. The experimental results suggest that the best catalyst is prepared by impregnating the carbon sample in 0.7 mol l⁻¹ oxalic acid solution for 24 h followed by being activated at 600 °C for 5 h under nitrogen atmosphere. After being treated with oxalic acid solution, the surface area and the acidity on the carbon surface increase. The experiments show that the carbon modified with oxalic acid can get a much higher NO removal efficiency than the original carbon.