Feasible ionic liquid-amine hybrid solvents for carbon dioxide capture

Abstract Ionic liquid (IL)-amine hybrid solvents have been proved to be an energy-saving system for CO 2 capture. Lack of experimental information on the diffusivity and heat of CO 2 absorption in IL-amine hybrid solvents hampers the wide application of IL in CO 2 capture. In this work, the effects of IL on absorption rate, solubility, diffusivity and heat of CO 2 absorption in feasible hybrids of 1-butyl-3-methyl-imidazolium nitrate ([Bmim][NO 3 ]) and monoethanolamine (MEA) have been elaborated using weight method, vapor liquid equilibrium and calorimetric measurement. The results showed that the addition of IL slightly decreases CO 2 loading under atmospheric pressure. Based on the measured solubility and calorimeter results, IL is beneficial to improve the physical absorption of CO 2 and reduce the heat of absorption in IL-amine hybrids. The diffusivity of CO 2 can be maintained at an acceptable level by controlling the concentration of IL. Considering CO 2 capacity, kinetics and heat of absorption, the hybrids of 30% MEA + 10% [Bmim][NO 3 ] + 60% H 2 O were recommended. Our work gives the meaningful insights on designing novel IL-amine hybrids for CO 2 capture.