Desulfurization Performance of Ether-Functionalized Imidazolium-Based Ionic Liquids Supported on Porous Silica Gel

Ether-functionalized imidazolium-based ionic liquids (EFIILs) [C(3)O(1)Mim][H3CSO3], [C(5)O(2)Mim][H3CSO3], and [C(7)O(3)Mim][H3CSO3] were supported onto porous silica gel particles via a facile impregnation method. The synthesized EFIILs/SiO2 were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and BrunauerEmmettTeller (BET). Results show that the EFIILs/SiO2 have good thermal stability, high porosity, and large specific surface area. The ability of both of the EFIILs and EFIILs/SiO2 to reversibly absorb gaseous sulfur dioxide (SO2) was experimentally investigated, and high capacity and rate for SO2 sorption were confirmed. The capacities reached 2.621 mol of SO2/mol of [C(3)O(1)Mim][H3CSO3], 3.106 mol of SO2/mol of [C(5)O(2)Mim][H3CSO3], and 3.453 mol of SO2/mol of [C(7)O(3)Mim][H3CSO3], which indicate that the SO2 sorption capacity increases with the increase of the ether chain length in the cation at 25 degrees C. The EFIILs/SiO2 have better adsorption properties than pure EFIILs, because the supporting materials/porous silica gel played an important role in the adsorption. The EFIILs/SiO2 system could be reused for several adsorptiondesorption cycles without loss of its initial capacity.