NH₃ selective catalytic reduction (SCR) of nitrogen oxides (NO_x) over activated sewage sludge char

The de-NO_x performance of sewage sludge chars activated physically using water vapor or chemically using KOH was evaluated. Characteristics of chars activated under different activation temperatures, water vapor concentrations, and KOH/char ratios were analyzed by N₂ adsorption-desorption and FT-IR. Chemically activated chars were more efficient in removing NO_x due to their higher surface area, oxygen functional group and NH₃ adsorption than physically activated chars. The de-NO_x performance of the activated chars is influenced more by chemical properties such as oxygen functional groups and NH₃ adsorption sites than by physical properties like specific surface area and pore volume.