Solubility of CO2 in aqueous mixtures of monoethanolamine and dicyanamide-based ionic liquids

Two low viscous ionic liquids (ILs), 1-(2-hydroxyethyl)-3-methyl-imidazolium dicyanamide ([C2OHmim][DCA]) and 1-butyl-3-methylimidazolium ([Bmim][DCA]) were selected to mixed with aqueous 30 wt% monoethanolamine (MEA) for CO2 absorption. The solubility of CO2 in the aqueous mixtures of MEA + ILs was measured over a range of CO2 partial pressure of 10–800 kPa and ILs concentrations from 10 to 50 wt% at 313.15 K and 333.15 K. Correlations of solubility as a function of CO2 partial pressure have been conducted with deviation of ±1.5%. Moreover, the density and viscosity of pure ILs and MEA + ILs + H2O systems with different IL mass fractions were measured at temperature varying from 293.15 to 333.15 K.