Absorption of carbon dioxide in the aqueous mixtures of methyldiethanolamine with three types of imidazolium-based ionic liquids

The absorption of carbon dioxide in the 4mol/L aqueous solution of methyldiethanolamine (MDEA) mixed with three types of ionic liquids, 1-butyl-3-methyl-imidazolium tetrafluoroborate ([bmim][BF₄]), 1-butyl-3-methyl-imidazolium acetate ([bmim][Ac]) and 1-butyl-3-methyl-imidazolium dicyanamide ([bmim][DCA]) were measured as a function of temperature, CO₂ partial pressure and concentration of ionic liquids in the solution. The data for aqueous MDEA+ILs solutions were obtained for temperature, CO₂ partial pressure and ionic liquids concentrations ranging from 303 to 333K, 100 to 700kPa and 0 to 2mol/L, respectively. The CO₂ loading in all the studied mixtures decreases with an increase in temperature and increases with an increase in the CO₂ partial pressure, at a given temperature. Also, it is found that the CO₂ loading decreases significantly as the ionic liquid concentration increases, but this reduction in solutions contained [bmim][BF₄] was less than other types of ionic liquids.