Preparation and SO2 Sorption/Desorption Behavior of an Ionic Liquid Supported on Porous Silica Particles

The ionic liquid 1,1,3,3-tetramethylguanidinium lactate (TMGL) was supported onto porous silica particles via a facile impregnation−vaporization method. The TMGL-supported particles gave high porosity and large specific surface area. The SO2 sorption/desorption properties of the silica-supported TMGL (TMGL−SiO2) were evaluated, and high SO2 sorption capacity and rate were achieved. Its capacity reached 0.6 g SO2/g TMGL in 15−30 min with pure SO2 gas and 0.15 g SO2/g TMGL in 17 h with a N2/SO2 mixture gas that contained 2160 ppm SO2. The SO2 concentration was reduced to 12.6 ppm after sorption. The TMGL−SiO2 system could be reused for many sorption/desorption cycles without change in its capacity. It was also characterized by good mechanical strength and thermal stability at temperature up to 130 °C. The SO2 sorbent system appears to be useful in gas desulfurization.