A new strategy to effectively capture and recover SO2 based on the functional porous liquids

The modern fossil fuel utilisation industry has proposed higher requirements for SO2 removal to meet cleaner production requirements, such as the reusability of desulfurisers, avoidance of equipment corrosion, and recovery of sulfur resources. This study constructed a novel type III porous liquids (PLs) which combine the fluidity of liquids and the permanent porosity of solid materials by uniformly dispersing porous metal-organic framework particles of NENU-3a into a steric solvent of polydimethylsiloxane, and used them for SO2 capture and recovery. A novel desulfurisation system was developed using tert-butanol peroxide as the oxidant and water as the extractant. The endowed porosity of the PLs significantly improved the SO2 capture performance, and the polydimethylsiloxane solvent acted as a protective screen to prevent the corrosion of SO2 to the equipment. The prepared PLs exhibited excellent reusability owing to their structural stability. Furthermore, the captured SO2 was fully oxidised to SO42- due to the excellent catalytic oxidation activity of encapsulated polyoxometalates in NENU-3a, thus obtaining a high-purity sulfuric acid product. This work not only proposes a novel technology to realise the resource ability of SO2 under environmentally friendly conditions but also opens a new window for the rational treatment of emitted SO2 gas based on PLs to meet the new requirements for fossil fuel utilisation.