Abstract
In this work, the CO2 adsorption performance of metal-organic frameworks (MOFs) impregnated with ionic liquids (ILs) was studied using quartz crystal microbalance (QCM) at the temperature of 298.15 K and pressures up to 5 bar. The hybrid composites consist of aluminum terephthalate metal-organic framework (AlTp) impregnated of 1-butyl-4-methyl pyridinium and 1-butyl-3-methylimidazolium-based ionic liquids (ILs) with different anions, viz. tetrafluoroborate ([BF4]-), thiocyanate ([SCN]-), chloride ([Cl]-), and bromide ([Br]-). ILs-impregnated AlTp synthesized was characterized using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), the thermogravimetry analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. CO2 adsorption isotherms of the IL/AlTp composites and AlTp were measured to evaluate the ILs effect on the CO2 adsorption of the AlTp. Comparison of CO2 adsorption in ILs/AlTp with different anion ([Cl]-, [Br]-, [SCN]-, [BF4]-) reveals that CO2 adsorption in ILs/AlTp was increased in the order as: [BF4]- < [SCN]- < [Br]- < [Cl]-. The results show that [BMPyr][Cl]/AlTp the highest CO2 adsorption capacity, 2.6 times higher than that of AlTp at 5 bar and 298.15 K which helps to guide the logical design of new mixtures for gas separation applications. Also, adsorption/desorption test show that regeneration performance of [BMPyr][Cl]/AlTp is 96.53% after five consecutive cycles adsorption/desorption.