Intensification of NO2 removal in sulfite solutions with reusable copper chloride: Mechanism and process parameters

A novel strategy was proposed to scrub NO x pollutant originated from sintering flue gases by oxidation combined with wet flue gas denitrification technology. CuCl 2 that could be adopted repeatedly was introduced as an additive into the sulfite solution to enhance NO 2 removal. Comparing with the sulfite solution (0.05 mol/L), the absorption efficiency improved from 75% to 100%, and the stabilization period extended from 10 to 40 min notably with the addition of CuCl 2 . The intensification by CuCl 2 addition was related to the formation of CuCl during the reaction of CuCl 2 and SO 3 2− , which was found to be more effective in removing NO 2 . Afterwards, CuCl transformed to Cu 2+ substance again and this mutual transformation between CuCl and Cu 2+ substance indicated a cyclic use of CuCl 2 additive. Moreover, the feasible reaction pathway was further proved by DFT calculations. Additionally, the investigation on NO 2 absorption at various operating parameters provided theoretical support for the practical application of CuCl 2 in denitrification.