科创中国

Efficient and reversible capture of SO₂ by pyridinium-based ionic liquids

• 摘要：

  A series of thermally stable pyridinium-based ionic liquids (ILs), including [C₄Py][BF₄], [C₆Py][BF₄], [C₈Py][BF₄], [C₄³MPy][BF₄], [C₆³MPy][BF₄], [C₈³MPy][BF₄], [C₄Py][SCN] and [C₄Py][Tf₂N], were firstly applied as new absorbents for SO₂ capture. It was found that among the investigated ILs [C₄Py][SCN] has the highest absorption capacity of 0.841 gSO₂gIL^-1 under ambient conditions, which is much higher than that of the most reported imidazolium-based ILs. The selectivity for SO₂/CO₂, SO₂/N₂ and SO₂/O₂ was also studied and the higher selectivity for SO₂ to other gases using the [C₄Py][SCN] was achieved. Moreover, how the water content affects the absorption capacity of SO₂ was further investigated. The absorption mechanism was studied using FT-IR and NMR spectroscopy, as well as Quantum Chemical calculation and Molecular Dynamic (MD) simulation. It was demonstrated that the physical absorption occurs in pyridinium-based ILs for SO₂ capture. Comparing with cation of IL, anion plays a dominant role in SO₂ absorption, which was proved both by the interaction enthalpy of IL-SO₂ using Quantum Chemical calculation and the experimental results. MD simulation results further confirmed that the higher absorption capacity of SO₂ in [C₄Py][SCN] is mostly attributed to the stronger electrostatic interaction between the anion and SO₂. In addition, the [C₄Py][SCN] can still keep the stable absorption performance after five cycles of absorption and desorption, implying the pyridinium-based ILs show great potentials as cost effective and green absorbents for SO₂ capture applications.

• 作者：

  Shaojuan Zeng;Hongshuai Gao;Xiaochun Zhang;Haifeng Dong;香平 张;锁江 张

• 刊名：

  Chemical Engineering Journal

• 在线出版时间：

  2014-9-1