As a successive work towards exploring suitable IL-based absorbents for SO₂ absorption from flue gas, we developed a species of new dicationic ionic liquids (DILs) with the combination of ether-functionalized dication and N-heterocyclic anions. These dual-functionalized DILs possessed high thermal stability, low vapour pressure, and high SO₂ capacity. The solubilities of SO₂ in the DILs increased with declining of the temperature and elevating of the SO₂ concentration. Notably, the available loading capacity of SO₂ in DIL₄ was up to 0.267 g SO₂·(g DIL)^-1 at 313.2 K when the concentration of SO₂ in the feed gas was 2000 ppm, which was exceedingly significant for trapping SO₂ from the flue gas with low content of SO₂. The regeneration experiments demonstrated that the absorption capacities of SO₂ in DIL₄ kept unchanged after six successive cycles of absorption/desorption. The absorption mechanisms based on the results of ¹H NMR, FTIR analysis and quantum chemical calculations indicated that both physical and chemical interactions between the SO₂ molecules and DIL₄ could be found in spite of different concentrations of SO₂.

作为探索适用的基于烟道气吸收SO ₂的基于IL的吸收剂的后续工作，我们开发了一种新的离子型离子液体（DIL），其结合了醚官能化的离子型和N-杂环阴离子。这些双功能DIL具有高热稳定性，低蒸汽压和高SO ₂容量。随着温度的降低和SO ₂浓度的升高，DIL中SO ₂的溶解度增加。值得注意的是，当SO ₂浓度为313.2 K时，DIL ₄中SO ₂的可用负载量高达0.267 g SO ₂ ·（g DIL）^-1进料气体为2000ppm，这是用于捕集SO极其显著₂与SO的低含量从烟道气₂。再生实验表明，DIL ₄中SO ₂的吸收容量在连续六个吸收/解吸循环后保持不变。基于¹ H NMR，FTIR分析和量子化学计算结果的吸收机理表明，尽管SO _2的浓度不同，仍可以发现SO ₂分子与DIL ₄之间的物理和化学相互作用。