Thermophysical properties and water sorption characteristics of 1-ethyl-3-methylimidazolium acetate ionic liquid and water binary systems

Non-corrosive ionic liquids with negligible vapor pressure are potential substitutes for traditional absorbents used in absorption refrigeration chillers. In this study, we aimed to investigate the thermophysical properties and water sorption characteristics of the 1-ethyl-3-methylimidazolium acetate ([EMIm]Ac) ionic liquid and water binary systems. Density, thermal conductivity, specific heat capacity, viscosity, and surface tension were determined at various [EMIm]Ac mass fractions in the 20–100% range, as well as at various temperatures. In addition, mathematical relationships between the measured thermophysical properties and the studied variables (temperature and mass fraction) were developed. The water sorption and desorption performance were investigated for the [EMIm]Ac aqueous solution. Modified two-step sorption mechanism and linear desorption kinetics were proposed for the absorption and desorption process, respectively. These properties are helpful for the calculation and evaluation of the performance of the absorption and desorption based on the [EMIm]Ac/water working pair.