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 N-2/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 degrees C. The SO2 sorbent system appears to be useful in gas desulfurization.