Highly Efficient and Reversible SO2 Capture by Surfactant-Derived Dual Functionalized Ionic Liquids with Metal Chelate Cations

A series of dual functionalized ionic liquids with metal chelate cations from surfactant and alkali metal salt were designed, prepared, and used for SO2 capture. The effect of metal ions, coordination number, anionic structures, temperature, and pressure on SO2 absorption was investigated. The interaction of these functionalized ionic liquids with SO2 was explained by spectroscopic investigation. The results showed that these metal-containing ionic liquids exhibited high absorption capacity through a combination of physical and chemical interaction of SO2 with basic anions and ether-containing cations as well as excellent reversibility (21 recycles). Considering the easy preparation, low cost, and excellent performance, these dual functionalized metal-containing ionic liquids provide significant improvements over traditional ionic liquids, indicating the promise for industrial application in SO2 capture.