Enhancement of nitric oxide removal by ammonia on a low-rank coal based carbon by sulphuric acid treatment

Abstract

This work presents a study of the effect of wet sulphuric acid treatment and gas-phase treatment with SO 2 + O 2 + H 2O on the catalytic activity of a low-rank coal-based carbon for the nitric oxide reduction with ammonia. Carbons were characterized by N 2 adsorption, TPD, and FTIR in order to assess how the surface chemistry and the texture of carbons change after the treatments. A great amount of oxygenated functional groups both CO 2 and CO evolving ones are produced by liquid-phase sulphuric acid treatment. However, the amount of those groups after gas-phase treatment with SO 2 + O 2 + H 2O is lower, in particular the CO 2 evolving groups. The catalytic activity of carbons was examined in a fixed bed reactor at 150 °C in a gas flow containing NO, O 2, N 2 and NH 3, the effluent concentration being monitored continuously during the reaction. The obtained results indicate that an appropriate balance between the type of oxygen functional groups and surface area available to the reactant gas are required to reach high levels of NO conversion.