Simultaneous removal of NOx and SO2 by low-temperature selective catalytic reduction over modified activated carbon catalysts

Abstract

A series of modified porous activated carbon (AC) catalysts prepared by impregnation were investigated for the low-temperature (≤250°C) selective catalytic reduction (SCR) of NO_x with NH₃ with simultaneous removal of SO₂. The effects of various preparation conditions and reaction conditions on NO and SO₂ conversions were observed, such as support type, active components, copper loading, calcination temperature and presence of H₂O and O₂. The modified AC catalysts were characterized by BET, XRD, TG and TPX methods. The activity test results showed that the optimal catalyst is 15% Cu/WCSAC which can provide 52% NO conversion and 68% SO₂ conversion simultaneously at 175°C with a space velocity of 30000 h^‒1, and the optimal calcination temperature was 500°C. The presence of H₂O could inhibit NO conversion and promote the SO₂ conversion. The effect of O₂ (0–5%) was evaluated, and the NO and SO₂ conversions were best when the concentration of O₂ was 3%. Research demonstrated that Cu/WCSAC catalyst was a kind of potential catalysts due to the amorphous phase, high specific areas and high active ability.