Density and Viscosity of Aqueous (Ammonia plus Carbon Dioxide) Solutions at Atmospheric Pressure and Temperatures between 278.15 and 318.15

The density and the viscosity of aqueous (NH3 + CO2) solutions have been measured at atmospheric pressure over a temperature range of 278 to 318 K and apparent concentrations of solute between 4 and 10 mol(NH3) kg(H2O)(-1) for NH3 and between 1 and 5.2 mol(CO2) kg(H2O)(-1) for CO2. Solute loss from the aqueous solution associated with the high equilibrium partial pressure of NH3 and of CO2 has been limited by devices and protocols developed ad-hoc for sample preparation and density and viscosity measurement. Solid or vapor formation out of the initial liquid mixture has been avoided by means of a thermodynamic model-driven design of experiments. The experimental values gathered in this work have been used to obtain empirical models of density and viscosity, as a function of the apparent concentration of solutes, that is, NH3 and CO2, and temperature, that are able to reproduce the experimental values in all cases with deviations below 1.1% for density and below 9.4% for viscosity. While it is the first time that, to our knowledge, experimental viscosity data of aqueous ammonia solutions loaded with CO2 are added to the literature, the density model developed in this work is also able to reproduce experimental density data from literature with deviations below 1.5%, even outside the boundaries of the experimental conditions considered in this work.