Sorption constant

Swann R, Laskowski D, McCAll P, et al. 1983. A rapid method for the estimation of the environmental parameters octanol/water partition coefficient, soil sorption constant, water to air ratio, and water solubility. Residue Rev 85 18-28. 

Soil Sorption Constant - Soil/Water (Knp.). The distribution of a chemical between soil and water can be described with an equilibrium expression that relates the amount of chemical sorbed to soil or sediment to the amount in the water at equilibrium. 

The primary active surface that interacts with the chemical in the sorption process has been shown to be the organic fraction of the soil(6-10). Therefore, the sorption characteristics of a chemical can be normalized to obtain sorption constant based on organic carbon (K ) which is essentially independent of any soil. 

K - sorption constant in distilled water ([g compound/g OV-1]/ [g compound/g water])... 

The data of Loukidou et al. (2004) for the equilibrium biosorption of chromium (VI) by Aeromonas caviae particles were well described by the Langmuir and Freundlich isotherms. Sorption rates estimated from pseudo second-order kinetics were in satisfactory agreement with experimental data. The results of XAFS study on the sorption of Cd by B. subtilis were generally in accord with existing surface complexation models (Boyanov et al. 2003). Intrinsic metal sorption constants were obtained by correcting the apparent sorption constants by the Boltzmann factor. A 1 2 metal-ligand stoichiometry provides the best fit to the experimental data with log K values of 6.0 0.2 for Sr(II) and 6.2 0.2 for Ba(II). 

Sutton. C., Calder, J.A. (1975) Solubility of alkylbenzenes in distilled water and seawater at 25°C. J. Chem Eng. Data 20, 320-322. Swann, R.L., Laskowski, D.A., McCall, P.J., Vender Kuy, K., Dishburger, J.J. (1983) A rapid method for the estimation of the environmental parameters octanol/water partition coefficient, soil sorption constant, water to air ratio, and water solubility. Res. Rev. 85, 17-28. 

Most sorption/desorption kinetic models fit the data better by including an instantaneous, non-kinetic fraction described by an equilibrium sorption constant. 

Kanazawa, J. Relationship between the soil sorption constants for pesticides and their physicochemical properties, Environ. Toxicol Chem., 8(6) 477-484, 1989. 

With the lowering of the US arsenic drinking water standard (MCL) from 50 to 10 pg L-1 (Appendix E), water treatment facilities may have had to modify their procedures to comply with the new standard. Boccelli, Small and Dzombak (2005) identifies some of the factors associated with Fe(III) chloride coprecipitation that might require modification while still maintaining reasonable costs. Besides the influent arsenic concentration and Fe(III) chloride dose, other critical factors in improving arsenic removal may include pH, the calcium and major anion concentrations of the influent, the volume of sludge, equilibrium sorption constants, and filter efficiency. 

ASTM. 1987b. Standard test method for determining a sorption constant (koc)for an organic chemical in soil and sediments. ASTM 1195 - 87, American Society for Testing and Materials, Philadelphia, PA, pp. 731-737. 

The permeability P of a gas through a polymer can be measured directly by determining the transport of mass through a membrane per unit time. The sorption constant S can be measured by placing a saturated sample into an environment, which allows the sample to desorb and measure the loss of weight. As shown in Fig. 2.63, it is common to plot the ratio of concentration of absorbed substance c t) to saturation coefficient Coo with respect to the root of time. 

Figure 8.10 Sorption constants for Cu, Zn and Cd on natural oxyhydroxides as a function of pH obtained from field measurements. The points were obtained in the Carnon River, UK (V, Johnson, 1986) in 40 sites in Canadian lakes representing a variety of geological settings, lake pH values, and trace element concentrations in the sediments and in the overlying waters (O, Tessier, 1992) and in streams affected by acid mine drainage (A, Chapman et at., 1983). Log= Fe-M / Fe-ox [Mz+] (adapted from Tessier, 1992).

American Society for Testing and Materials, Standard Test Method for Determining a Sorption Constant (Koc) for an Organic Chemical in Soils and Sediments, Philadelphia, PA, 1993. 

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