Equilibrium partition coefficients waters

Concentrations in Water and Particles. In order to obtain the rates of reaction, the concentrations of the two monomers and the chain transfer agent in the water and polymer phases were calculated using equilibrium partition coefficients (H). ... 

Cheng, W.-H., Chu, F.-S., Liou, J.-J. (2003) Air-water interface equilibrium partitioning coefficients of aromatic hydrocarbons. Atmos. Environ. 37, 4807 -815. 

Now, because the water-borne radioactive element is predominantly associated with the colloids, we no longer have a need for the distribution coefficient. There will still be a partitioning because the major portion of the radioactive elements will still be adsorbed to the sediment. This is a separate equilibrium partitioning coefficient, requiring a new experiment on the clay sediments and the colloids present. The partitioning colloid-clay ratio would most likely be dependent on the surface areas of each present in the sediments. A separate size distribution analysis has resulted in a sediment-colloid surface area ratio of 99 1 for the sediment. This results in a colloid retardation coefficient oiRc = 100 rather than Ri = 4.2 x 10 or i 2 = 6 x 10. ... 

Dissolved fraction and equilibrium partition coefficient, at sediment-water interface ... 

Since the open water column is nearly pure water (op =1, rs p = 0), for compounds with small to moderate solid-water distribution ratios (Kd < 10 m3kg ), the above equilibrium partition coefficient can be simplified to ... 

During mastication, nonvolatile flavor molecules must move from within the food, through the saliva to the taste receptors on the tongue, and the inside of the mouth, whereas volatile flavor molecules must move from the food, through the saliva and into the gas phase, where they are carried to the aroma receptors in the nasal cavity. The two major factors that determine the rate at which these processes occur are the equilibrium partition coefficient (because this determines the initial flavor concentration gradients at the various boundaries) and the mass transfer coefficient (because this determines the speed at which the molecules move from one location to another). A variety of mathematical models have been developed to describe the release of flavor molecules from oil-in-water emulsions. 

Results. Table XIV presents some results obtained when using this method for measuring the equilibrium partition coefficient between distilled water and several silica gels. The sorption of phenanthrene is shown to be a function of surface area for these materials. Tables XV through XVIII present the results obtained for the partitioning of a PAH... 

Erythromycin extraction. Lye and Stuckey [81] reported the equilibrium partitioning of a microbial secondary metabolite, erythromycin, using both CLAs [formulated from 1% (w/v) Softanol 120 (alcohol ethoxylate type, Honeywill Stein) in decanol and 0.5% (w/v) SDS in water] and surfactant-containing, two-phase systems. The equilibrium partitioning of erythromycin was found to be strongly influenced by the extraction pH, and exhibited a marked change on either side of the of the molecule. A modified form of the Henderson-Hasselbach equation [16] could be used as a simple design equation to predict the equilibrium partition coefficient, as a function of pH. For extraction experi-... 

The steady-state permeability across the stratum comeum (SC) from an aqueous vehicle into an infinite sink depends on the diffusivity of the chemical in the SC (D ), the SC thickness (LJ, and the equilibrium partition coefficient between the SC and the water vehicle K-... 

Equilibrium partition coefficient between the SC and water for the absorbing... 

The final partitioning of fission product iodine between the sump water and the atmosphere of the containment is determined by the equilibrium partition coefficient as will be discussed in more detail in Section 7.4.3.1., this figure depends on several parameters, such as iodine concentration and sump water pH and, to a lesser extent, temperature. As can be seen from Fig. 4.13., the iodine partition coefficient increases with decreasing iodine concentration in the solution this behavior is the consequence of the shift in the h hydrolysis reaction towards a lower I2 equilibrium fraction at lower total iodine concentration. Below a concentration of about 10" g/1, however, the partition coefficient remains virtually constant, an effect which has been attributed to the volatility of the hydrolysis product HOI (Lin, 1981). This constant value is about l(f at pH 7 and 25 °C it applies as well for the concentration range to be expected in a loss-of-coolant accident. Concerning the HOI partition coefficient at 100 °C, several measurements yielding quite different values have been reported. The lowest one is 240 given by Lin (1981) Lemire et al. (1981) reported values between 100 and 1(1, while Wren and Sanipelli (1984) measured values between 7 10 and 3 10. Since the HOI compound was... 

Fission product iodine present in the pool water is assumed to show a more complicated behavior. The iodide species originally present in the primary coolant can be considered as non-volatile and will behave, therefore, in the same manner as, for example, Li+ and Cs+ however, it cannot be ruled out that I will be in part oxidized by air, forming volatile I2. Since the compartments in the annuli (and also in the nuclear auxiliary building) are not closed systems, but have a normal air circulation, the principles of calculation of I2 volatilization using an equilibrium partition coefficient cannot be applied. Assuming an instantaneous iodine partitioning according to the equilibrium values would result in a drastic overestimation of iodine release, since I2 transport from the liquid to the gas phase is controlled by kinetics. The main characteristic in this context is a boundary layer at the interface between the sump and the gas phase, which is saturated with iodine in accor-... 

The concept of the equilibrium sampler is analogous to that of the octanol-water equilibrium partition coefficient (fQ,w) used since the 1970s to predict the potential for persistent nonpolar contaminants to concentrate in aquatic organisms [71]. The use of equilibrium-t) e passive samplers in the aquatic environment depends on the development of a sampler-water partition coefficient (fCs ) defined as the ratio of sampler to water concentration of the compound of interest at thermod)mamic equilibrium. The other key parameter determining the utility of an equilibrium-type passive sampler is the time taken to reach an approximate equilibrium condition. A range of approaches applied in developing equilibrium-t)q)e passive samplers include polyethylene or silicon sheets of various volume to surface area ratio [72] and solid-phase microextraction techniques [73]. 

Octanol-Water Partition Coefficient (Kq )—The equilibrium ratio of the concentrations of a chemical in TT-octanol and water, in dilute solution. 

An important factor in determining the course of uptake, transport, and distribution of xenobiotics is their polarity. Compounds of low polarity tend to be lipophilic and of low water solubility. Compounds of high polarity tend to be hydrophilic and of low fat solubility. The balance between the lipophilicity and hydrophilicity of any compound is indicated by its octanol-water partition coefficient (K J, a value determined when equilibrium is reached between the two adjoining phases ... 

---