Nazim D. Azizov

Densities and Apparent Molar Volumes of Aqueous NaNO3 Solutions at Temperatures from 292 to 573 K and at Pressures Up to 30 MPa

Densities of four aqueous NaNO3 solutions (0.100, 0.303, 0.580, 0.892 mol-kg−1 H2O) have been measured in the liquid phase with a constant-volume piezometer immersed in a precision liquid thermostat. Measurements were made at ten isotherms between 292 and 573 K. The range of pressure was 0.1–30 MPa. The total uncertainty of density, pressure, temperature, and concentration measurements were estimated to be less than 0.06%, 0.05%, 10 mK, and 0.014%, respectively. Values of saturated densities were determined by extrapolating experimental P-ρ data to the vapor pressure at fixed temperature and composition. Apparent molar volumes were derived using measured values of density for the solutions and for pure water. The apparent molar volumes were extrapolated to zero concentration to yield partial molar volumes at infinite dilution. The temperature, pressure, and concentration dependence of partial and apparent molar volumes were studied. The measured values of density and apparent and partial molar volume were compared with data reported in the literature.

Viscosity for aqueous Li2SO4 solutions at temperatures from 298 to 575 K and at pressures up to 30 MPa

Viscosities of four aqueous Li 2 SO 4 solutions [(0.10, 0.28, 0.56, and 0.885) mol.kg -1 ] have been measured in the liquid phase with a capillary flow technique. Measurements were made at four isobars [(0.1, 10, 20, and 30) MPa]. The range of temperatures was from (298 to 575) K. The total uncertainties of viscosity, pressure, temperature, and concentration measurements were estimated to be less than 1.5%, 0.05%, 10 mK, and 0.014%, respectively. The reliability and accuracy of the experimental method were confirmed with measurements on pure water for three isobars [(10, 20, and 30) MPa] and at temperatures between (298 and 575) K. The experimental and calculated values from the IAPWS (International Association for the Properties of Water and Steam) formulation for the viscosity of pure water show excellent agreement within their experimental uncertainty (AAD is about 0.51%). A correlation equation for viscosity was obtained as a function of temperature, pressure, and composition by a least-squares method from the experimental data. The AAD between measured and calculated values from this correlation equation for the viscosity was 0.7% for pure water and 0.74% for the solutions. The measured values of viscosity at atmospheric pressure were compared with the data reported in the literature by other authors.

Viscosities, densities, apparent and partial molar volumes of concentrated aqueous MgSO4 solutions at high temperatures and high pressures

Density of two (2.224 and 2.535 mol kg−1) and viscosity of eight (0.085, 0.255, 0.437, 0.722, 0.923, 1.824, 2.291, and 2.623 mol kg−1) binary aqueous MgSO4 solutions have been measured with a constant-volume piezometer immersed in a precision liquid thermostat and a capillary flow technique, respectively. Measurements were made at pressures up to 30 MPa. The range of temperature was 288 to 398 K for the density measurements and 298–448 K for the viscosity measurements. The total uncertainty of density, viscosity, pressure, temperature, and composition measurements were estimated to be <0.06%, 1.6%, 0.05%, 15 mK, and 0.02%, respectively. The effect of temperature, pressure, and concentration on density and viscosity of binary aqueous MgSO4 solutions were studied. Apparent and partial molar volumes were derived using the measured values of density for the solutions. The viscosity data have been interpreted in terms of the extended Jones–Dole equation for strong electrolytes to accurately calculate the viscosity A- and B-coefficients as a function of temperature. The derived values of the viscosity A- and B-coefficients were compared with the results predicted by Falkenhagen–Dole theory of electrolyte solutions and calculated using the ionic B ±-coefficient data. The hydrodynamic molar volumes V k were calculated using the present experimental viscosity data.

Density, Apparent and Partial Molar Volumes, and Viscosity of Aqueous Na2CO3 Solutions at High Temperatures and High Pressures

Density of five (0.124, 0.334, 0.706, 1.055, and 1.123) mol kg-1 and viscosity of seven (0.124, 0.2918, 0.334, 0.706, 0.8472, 1.055, and 1.123) mol kg-1 binary aqueous Na2CO3 solutions 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 dilution V¯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 viscosity A- and B-coefficients as a function of temperature. The Arrhenius–Andrade parameters ηA and b = Ea/R (where Ea is the flow activation energy) were calculated using present experimental viscosity data. The effective pressures Pe due to the salt (Na2CO3) in water in the TTG (Timmann-Tait-Gibson) model were calculated from present viscosity measurements.