CALF-20-Based Porous Liquids for Enhanced SO2 Capture

Abstract Currently, efforts are being made to develop desulfurization technologies featuring high desulfurization efficiency, renewable desulfurizers, and low corrosivity. In this study, a comparative study was conducted of SO2 capture by ten kinds of metal–organic framework (MOF)-based porous liquids. Calgary framework-20 (CALF-20)/poly(ethylene glycol) dimethyl ether (NHD) with pore width of 5.2 Å × 5.7 Å are found to be optimal for SO2 capture, exhibiting an a(b)dsorption capacity of 0.12 mol/L under 0.1 bar. The selectivity of SO2/N2 and SO2/CO2 achieves 562 and 51, respectively, and the uptake enthalpy for SO2 is only 30.44 kJ·mol–1. Furthermore, after multiple breakthrough experiments, the uptake still remained unchanged. Meanwhile, process simulations were conducted; when SO2 mol % (≥99.95%) is in the product gas, the capture work is only 0.946 GJ/t SO2. Additionally, the saturated CALF-20-based porous liquids exhibited low corrosivity to carbon steels even after being immersed for 60 days; this anticorrosive absorbent reveals the potential for industrial SO2 capture.