Experiment and model for the surface tension of amine-ionic liquids aqueous solutions

The surface tension (γ) of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4])-monoethanolamine (MEA), 1-butyl-3-methylimidazolium bromide ([Bmim][Br])-MEA, [Bmim][BF4]-diethanolamine (DEA) and [Bmim][Br]-DEA aqueous solutions was measured by using the BZY-1 surface tension meter. The temperature ranged from (293.2 to 323.2) K. The mass fraction of amines and ionic liquids (ILS) respectively ranged from 0.15 to 0.30 and 0.05 to 0.10. A thermodynamic equation was proposed to model the surface tension of amines-ILS aqueous solutions and the calculated results agreed well with the experiments. The effects of temperature, mass fraction of amines and ILS on the surface tension were demonstrated on the basis of experiments and calculations.