Removal of NO_x from simulated flue gas by aqueous-phase oxidation combined with absorption

Removal of NO_x from simulated flue gas by aqueous-phase oxidation combined with absorption was studied in a self-designed bubble reaction system when NaClO₂ and Na₂SO₃ solution were used as oxidant and absorbent solution, respectively. The effects of gas-phase SO₂ concentration, Na₂SO₃ and NaClO₂ dosages and pH on NO oxidation and NO_x removal were investigated. The results show that the presence of SO₂ is favorable for NaClO₂ consumption because SO₂ reacts with oxidant more easily than NO. NO is easily oxidized into NO₂ under low pH conditions, but also decomposes more NaClO₂ into ClO₂. Partial NO is absorbed by alkaline solution in the presence of NO₂ while this absorption reaction does not occur in the absence of NO₂. SO₂ promotes the absorption removal of NO₂.