Isopiestic Investigation of the Systems FeCl2–(Na, K, Mg, Ca)Cln–H2O at 298.15 K

Isopiestic measurements were performed in aqueous FeCl2-solutions and in ternary systems of the type FeCl2–MCln–H2O (M = Na, K, Mg, Ca). Numeric data for water-isoactivity lines are presented and pertinent osmotic coefficients are calculated. The obtained data were recalculated using Pitzer’s equations. Pertinent parameters are given.

Isopiestic Investigation of the Systems Fe2(SO4)3–H2SO4–H2O, FeCl3–H2O, and Fe(III)–(Na, K, Mg, Ca)Cln–H2O at 298.15 K

Isopiestic measurements were performed in binary and ternary systems of the type Fe2(SO4)3–H2SO4–H2O, FeCl3–H2O, and FeCl3–MCln–H2O (M = Na, K, Mg, or Ca). Numeric data for water isoactivity lines are presented and osmotic coefficients are calculated. The obtained data were recalculated using Pitzer’s equations. Pertinent parameters are given.

Solubility equilibria in multicomponent oceanic salt systems from t = 0 to 200 °C. Model parameterization and databases

In this paper the application of Pitzer's equations for modeling of solubility equilibria in the hexary oceanic salt system Na+, K+, Mg2+, Ca2+ // Cl­, SO42­­H2 O and its subsystems over large temperature intervals is discussed. Lack of ternary solution data considerably restricts the use of the equations as an evaluation tool for the quality of solubility data. Models optimized for the available data in two temperature intervals have been derived. Since Pitzer's model gives no guidance for temperature dependence, the number of parameters is dominated by temperature coefficients. Thus, for extended temperature intervals other approaches like the Cohen-Adad formalism can be advantageous in solubility data evaluation.