Distribution coefficients from

The principal rubidium salts which would probably have been present in the sediment (chloride, sulfate, bicarbonate, etc.) are all soluble in water. As discussed later, the red clay was thoroughly dialyzed prior to use (including prior to analysis by emission spectroscopy). Any rubidium salts initially present in the clay samples would, therefore, have been removed by the dialyzing solution. Hence, it was assumed that the rubidium concentration given in Table I represented sorbed rubidium which had been in equilibrium with the rubidium in the original interstitial seawater. Then when calculating distribution coefficients from experimental data, the concentration given in Table I was used as the initial clay-phase rubidium concentration, rather than zero as used with most of the other species studied. 

Estimate the goethite-water distribution coefficients from 10 mM NaCl aqueous solutions of benzoic acid (pKia = 4.1) at 50 nM at pHs 4, 5, and 6 to a synthetic iron oxyhydroxide, goethite, with the following properties (from Evanko and Dzombak, 1998) ... 

Tab. 8-16. Error in the prediction of metal distribution coefficients from the water components...

Sorption Parameters and Distribution Coefficients from Initial Mass Isotherms... 

Csizmadia, F. Tsantili-Kakoulidou, A. Pander, I. Darvas, F. Prediction of distribution coefficient from structure. I. Estimation method. J. Pharm. Sci. 1997, 86, 865-871. 

Reymond, F. Steyaert, G. Carrupt, P.A. Testa, B. Girault, H. Ionic partition diagrams a potential-pH representation. J. Am. Chem. Soc. 1996,118, 11,951-11,957. Tsantili-Kakoulidou, A. Panderi, I. Csizmadia, F. Darvas, F. Prediction of distribution coefficient from structure, II. Validation of prologD, an expert system. J. Pharm. Sci. 1997, 86, 1173-1179. 

Figure 11. Countercurrent multistage extraction with immiscible solvents and constant distribution coefficient. (From firfrac/Zon by R. E. Treybal. Copyright 1963,...

Starting with activity coefficients, which can be determined from (5-33), one can form distribution coefficients from (4-31). For partially miscible pairs, the preferred procedure for obtaining van Laar constants is a best fit of activity... 

The third factor stems from the departure of the adsorption isotherm or distribution coefficient from linearity. This factor can be easily understood by assuming an ideal colunm free from the other band-spreading effects, and a single-component isotherm. This simplification is quite valid for high-resolution columns. 

Eariy res em-screoiing experiments are summarized by Marcus and Kertes in a foim sudi as shovrn in Figs. 8.3-1 and 8.3-2. Figure 8.3-1 presents low-concentration distribution coefficient values ftn-various metals in a SX solution (rfTOPO in toluene for several concentrations of hydrochloric acid in die aqueous phase. Figure 8.3-2 shows a similar presentation of distribution coefficients from sulfuric add solutions into undiluted TBP. 

The effect of sweating can be seen in Figure 15.5 by a decrease of the distribution coefficient from about 0.4 to 0.2 at a growth rate of about 0.3 x 10 m/s, as well as from about 0.6 to 0.3 at a growth rate of about 1.7 x 10 m/s. Therefore, sweating can even reach in individual cases the same purification as by an additional (a second) crystallization step [8,10]. The results shown in Figure 15.5 were obtained... 

DISTRIBUTION COEFFICIENTS FROM EMPIRICAL CORRELATIONS OF TEMPERATURE AND COMPOSITION... 

A solution has the following composition, expressed as mole fraction ethane, 0.0025 propane, 0.25 isobutane, 0.185 n-butane, 0.560 isopentane, 0.0025. In the following, the pressure is 10 bars (145 Ibf/in ) abs. Use equilibrium distribution coefficients from the Depriester nomograph (see Illustration 9.3). 

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