Density, Apparent and Partial Molar Volumes, and Viscosity of Aqueous Na2CO3Solutions at High Temperatures and High Pressures

Abstract

Density of five (0.124, 0.334, 0.706, 1.055, and 1.123) mol kg-1and viscosity of seven (0.124, 0.2918, 0.334, 0.706, 0.8472, 1.055, and 1.123) mol kg-1binary aqueous Na2CO3solutions have been measured with a constant-volume piezometer and capillary flow techniques, respectively. Measurements were performed at pressures up to 52MPa for the density and 40MPa for the viscosity. The range of temperature was from 299 to 577K for density and from 293 to 478K for the viscosity. The total uncertainty of density, viscosity, pressure, temperature, and composition measurements was estimated to be less than 0.06%, 1.6%, 0.05%, 15mK, and 0.02%, respectively. Apparent molar volumes were derived using measured values of density for the solutions and for pure water calculated with IAPWS formulation. The effect of the thermodynamic variables (temperature, pressure, and concentration) on density, apparent and partial molar volumes, and viscosity of Na2CO3(aq) solutions was studied. The derived apparent molar volumes have been interpreted in terms of the Pitzer’s ion-interaction model of electrolyte solutions to accurate calculates the values of partial molar volumes at infinite dilutionV¯2∞and the second (BV) and third (CV) virial coefficients for the apparent molar volume as a function of temperature. The viscosity data have been analyzed and interpreted in terms of extended Jones–Dole equation for the relative viscosity (η/η0) of strong electrolyte solutions to accurate calculate the values of viscosityA- andB-coefficients as a function of temperature. The Arrhenius–Andrade parametersηAandb = Ea/R(whereEais the flow activation energy) were calculated using present experimental viscosity data. The effective pressuresPedue to the salt (Na2CO3) in water in the TTG (Timmann-Tait-Gibson) model were calculated from present viscosity measurements.