Impregnation of amine functionalized deep eutectic solvents in NH(2)-MIL-53(Al) MOF for CO(2)/N(2) separation

To improve the CO(2)/N(2) separation performance of metal–organic frameworks (MOFs), amine functionalized deep eutectic solvents (DESs) (choline chloride/ethanolamine (DES1), choline chloride/ethanolamine/diethanolamine (DES2), and choline chloride/ethanolamine/methyldiethanolamine (DES3)) confined in the NH(2)-MIL-53(Al). NH(2)-MIL-53(Al) impregnated with DES was synthesized and characterized using N(2)-sorption analysis and Fourier transform infrared (FTIR) spectroscopy. Morphology of the synthesized MOFs was investigated using scanning electron microscopy (SEM). Also, elemental analysis was determined by energy-dispersive X-ray spectroscopy (EDX). CO(2) adsorption isotherms of amine-functionalized DESs impregnated NH(2)-MIL-53(Al) were measured at temperatures range of 288.15–308.15 K and pressures up to 5 bar. The results reveal that the impregnated MOF with functional group of amine DES improves separation performance NH(2)-MIL-53(Al). CO(2) adsorption capacity of DES1/NH(2)-MILS-53(Al) was twofold respect to of pristine NH(2)-MIL-53(Al) at 5 bar and 298.15 K; which helps to guide the logical design of new mixtures for gas separation applications. Also, the heat of adsorption for the synthesized NH(2)-MIL-53(Al) and DESs/NH(2)-MIL-53(Al) were estimated. Most importantly, CO(2) chemisorption by NH(2) group in the sorbent structure has a significant effect on the adsorption mechanism.