[Adsorption performances for sulfur dioxide using imidazole ionic liquids].

To discover the SO2 adsorption laws of ionic liquids in simulating flue gas, the SO2 adsorbents 1-butyl-3-methylimidazolium chloride ([Bmim] Cl), 1-butyl-3-methylimidazolium nitrate ([Bmim] NO3), 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim] BF4) and 1-amyl-3-methylimidazolium chloride [C5 mim] Cl ionic liquids were synthesized. The performances were studied under different conditions and the general rules of regeneration were explored. And the diversification of [Bmim] Cl chemical structures, which were pre-desulfated, post-desulfated and post-regenerated, were characterized by Fourier Transform Infrared Spectroscopy. The results illustrated that these ionic liquids all had the ability of SO2 adsorption, and the order of SO2 adsorption performances was [C5 mim] C1 > [Bmim] Cl > [Bmim] NO3 > [Bmim] BF4. The total SO2 adsorption amount of [C5 mim] Cl was 200. 8 mg/g, and the optimal adsorption temperature of [Bmim] Cl was 40 degrees C. The order of anions impacting adsorption performances of ionic liquids was Cl- > NO3- > BF4-. The sulfur capacity of ionic liquids decreased to 26.5 mg/g from 65.9 mg/g after desorption under the condition of heating (90 degrees C), vacuum (0.09 MPa) and 4.0 h. In addition, the chemical structures of ionic liquid had changed, and the forms of SO2 adsorbed by [Bmim] Cl were physico-chemical processes.