Theoretical prediction of the SO₂ absorption by hollow silica based porous ionic liquids

As an acid gas, sulfur dioxide (SO₂) has caused serious pollution to the environment. Therefore, SO₂ capture is crucial. The silica-based porous ionic liquid possesses not only the porosity and high specific surface area of hollow silica, but also the fluidity of the liquid. The absorption mechanism of SO₂ absorption by porous ionic liquids through density functional theory (DFT) was systematically studied in this paper. First six kinds of absorption sites were predicted, and then various analyses such as structure, energy, and electrostatic potential analysis (ESP) were employed after optimization. The results show that SO₂ has the strongest adsorptive interaction between the canopy and the silica sphere. In addition, the main force between the porous ionic liquid and SO₂ is hydrogen bonding and π-hole bonding. Finally, by increasing the degree of polymerization of the canopy, that is, increasing the number of ether groups, will be beneficial to the absorption of SO₂.