Ionic Liquid Functionalized 3D Mesoporous FDU-12 for Effective SO₂ Capture

The emission of SO₂ from the combustion of fossil fuels leads to many environmental issues. The incorporation of ionic liquids (ILs) on porous supports to produce supported ionic liquids is an effective technology for SO₂ capture. However, blockage of pore channels is one of the main problems of this technology, which results in a substantial decrease of absorption capacity. Herein, a novel type of ionic liquid, 1-methyl-3-(3-triethoxysilylpropyl) imidazolium tetrazolate, functionalized large pore sized 3D mesoporous FDU-12 sorbents has been synthesized through a chemical grafting method. The as-prepared materials are characterized using SAXS, N₂ adsorption, TEM, XPS, elements analysis, EDS mapping, and TGA and then the performance of these materials to capture SO₂ is studied. The IL@FDU-12 materials are found to exhibit a high absorption capacity of SO₂ up to 8.19 mmol SO₂/g-sorbent (i.e., 524.2 mg/g) and a fast absorption rate (ca. 6 min is needed to reach equilibrium) at 25 °C and 1 bar since blockage of pore channels is effectively avoided and the IL is highly dispersed in the channels. These materials can also be used for the effective capture of CO₂ (1 bar) and low content of SO₂ (10%). Moreover, they have excellent thermal stability and can be reused in many absorption/desorption cycles without loss of the high absorption capacity and fast sorption/desorption rate.