Simultaneous Removal of NO and SO2 from Flue Gas Using [Bmim]2FeCl4/Sulfolane Binary Mixtures

NO and SO 2 are the major pollutants of coal combustion. As superior absorbents, ionic liquids are environmentally friendly, are reusable, and can clean flue gases, such as CO 2 , SO 2 , and NO x . However, NO and SO 2 absorption with low concentration in flue gases under normal conditions is rarely studied. In this work, [Bmim] 2 FeCl 4 was synthesized and mixed with sulfolane for NO and SO 2 removal from flue gas. The investigated concentrations of NO and SO 2 were 1100 and 2500 ppm, respectively, which are close to real fuel gas conditions. Results showed that 30 wt % [Bmim] 2 FeCl 4 /sulfolane mixture performed the best absorption behavior. The presence of SO 2 could promote NO absorption by [Bmim] 2 FeCl 4 /sulfolane mixture. The 30 wt % [Bmim] 2 FeCl 4 /sulfolane mixture had removal efficiencies of 93.6 and 76.2% for NO and SO 2 , respectively. This mixture also showed great reusability for NO and SO 2 after six cycles of absorption. Fourier transform infrared (FTIR) spectrum indicated that SO 2 and NO removal by [Bmim] 2 FeCl 4 /sulfolane binary mixture was due to the chemical reaction between NO and [Bmim] 2 FeCl 4 and the physical absorption between SO 2 and sulfolane.