Setschenow constant

The D s are equivalent to the Setschenow constants and the Ws are equivalent to differences between Setschenow constants. 

Bca = binary ion-ion interaction parameter CCa ternary ion-ion interaction parameter Dca m = binary salt-molecule interaction parameter or Setschenow constant D = dielectric constant... 

A simple correlation was determined for estimating the Setschenow constants for a variety of organic solntes in seawater, which yields an overall reduction in solnbility by a factor 1.36 (Xie et al. 1997). The hydrophobicity of organic solutes increases by this factor, but the salting-out effect must be quantified when comparing the behavior of specific organic contaminants in fresh water and in subsnrface aqueous solutions. 

The presence of electrolytes in the aqueous phase (as occurs most commonly in seawater) generally causes a solubility reduction or "salting out" effect. This usually is expressed by the Setschenow constant K, namely... 

AS Mutual diffusion coefficient mVs cmVs k Setschenow constant L/gmol L/gmol... 

A dynamic coupled-column liquid chromatographic technique was used to obtain aqueous solubility data on 11 aromatic hydrocarbons. The aqueous solubility at 25° C was determined for each compound. The precision of replicate solubility measurements was better than 3%. The variation of the solubility of each compound with temperature is expressed in the form of either a quadratic or cubic equation based on a least-squares fit of the solubility to temperature. These equations can be used to interpolate the solubility to within 2% of the experimentally measured values between 5° and 30°C. Enthalpies of solution (AHJ were then calculated from the values obtained and Setschenow constants were calculated from the effect of salinity on solubility. This system was also used to investigate the partitioning of PAHs between aqueous solutions and some sediment samples. 

The variations of solubility with both temperature and salinity are reported. Enthalpies of solution (AHs) are calculated from the temperature dependence of the solubility, and the effect of salinity on solubility, expressed in terms of the Setschenow constant, is reported for each compound. 

Table XII. Setschenow Constants for Some Aromatic Hydrocarbons at 25°C...

Equilibrium constants for the steps shown in Table 26.3. Setschenow constant. 

As in Pawlikowski and Prausnitz s (S24) paper on Setschenow constants, Edwards et al. (PS, P6) used Bromley s theory of the additivity of single ion Interactions to estimate ion-ion and ion-mdecule interactions ... 

For describing the difference in the interactions between a molecular solute and two salts with the same anion equivalent to the difference between two Setschenow constants. 

Empirical expressions have been reported for presenting the Setschenow constants for a large variety of solutes and ions. Weisenberger and Schumpe [63] presented an expression for gaseous solutes that do not interact chanicaUy with the solvents (excluding, e.g., NHj, HCl, and CO in aqueous solutions) ... 

TABLE 7.6 Empirical Setschenow Constants and the Ionic Electrostriction Parameter... 

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