Batch equilibrium method

Captina silt loam pH 4.97 McLaurin sandy loam pH 4.43, batch equilibrium, Walton et al. 1992) 1.75 (average of 5 soils, sorption isotherms by batch equilibrium method-GC, Xing et al. 1994)... 

NIST SRM diesel particulate matter flocculation-based batch equilibrium method with 59-d equilibration time, air-bridge equilibrium with 123-d equilibration time, Nguyen et al. 2004)... 

C, batch equilibrium method, A2 alluvial grassland soil calculated values of expt 1,2,3-solvophobic approach, Krauss Wilcke 2001)... 

The pHp value of washed ACC which is the pH of the solution when the net charge on ACC piece dipped into it is zero, was determined in our previous work [4] using batch equilibrium method described by Babic et al. [5],... 

C, 25°C, Semiahmoo soil, batch equilibrium method-LSS, Madhun et al. 1986)... 

Absorption-Desorption Using a Batch Equilibrium Method (updated guideline, adopted January 21, 2000)... 

A batch equilibrium method, as a function of pH and shaking time, was performed to characterize the metal uptake properties of silica gel-immobiUzed-aminophenol and aminobenzoic acid. Studies were made and evaluated on the basis of column application of immobilized chelating sorbents for the removal of various metal ions from sugar cane molasses. These revealed that they have higher preference toward Mn(II), Fe(III), Co(II), Cu(II), and Zn(n) rather than alkali and alkaline earth metals.The structures of the modified silica gel phases are shown in Scheme 10. 

The ion-exchange properties of the p-CAF copolymer resins were determined by the batch equilibrium method (Gupta et al., 2008). The ion-exchange properties of all the... 

Desorption Using a Batch Equilibrium Method. Guideline 106. 

Under this umbrella, a number of different applications lie, amongst others the batch equilibration and equilibrium soil solution methods. According to the USEPA (1999), the former represents the most common laboratory method for determining partition coefficients—normally defined as Kd—both for contaminated sites studies and for predictions of chemicals behaviour in soils (OECD, 2002). The batch equilibration method consists of mixing a soil with a known amount of liquid (background electrolyte), which is then shaken into a slurry and allowed to equilibrate for an adequate time. The solution will be separated from the solids by centrifuging the slurry, resulting in a supernatant and a separated solid phase. The supernatant will, therefore, be removed, filtered and analysed. 

Adsorption of Strontium in Equilibrium-Type and Column Experiments. Laboratory batch equilibrium experiments were used as a rapid method for selecting ion exchangers for testing in columns. Distribution coefficients were obtained for strontium adsorption by equilibrating 1 g of resin or zeolite in 100 ml of basin water and agitating for 24 hr at ambient temperature. After centrifuging, the concenti ation of strontium-90 in the supernate was determined. Table VI shows the measured dis-... 

Two general methods, the analytical method and the synthetic method (Grant and Brittain 1995), are available for determining solubility. In the analytical method, the temperature of equilibration is hxed, while the concentration of the solute in a saturated solution is determined at equilibrium by a suitable analytical procedure. The analytical method can be either the traditional, common batch agitation method, or the more recent flow column method. In the synthetic method, the composition of the solute-solvent system is hxed by appropriate addition and mixing of the solute and solvent, then the temperature at which the solid solute just dissolves or just crystallizes is carefully bracketed. 

Since the adsorption coefficient is critical to the theoretical development, caution should be exercised in using a particular K value for a particular soil and pesticide. The most common method used to measure adsorption is by the batch equilibrium technique, in which soil samples are equilibrated with a series of pesticide concentrations. However, the equilibrium time is critical, and may not represent adsorption under field conditions where the pesticide is moving in the solution phase. Consequently, flow equilibrium methods have also been developed (29). 

A Fortran IV computer program developed by Redifer and Wilson (10) was used to predict thermodynamic equilibrium compositions for 400-700°K and 1 atm total pressure. The calculations are based on a procedure presented by Meissner, Kusik, and Dalzell (11) in which the set of simultaneous reactions is simplified to a set of series-consecutive reactions. Each reaction is carried out in turn on the reactant mixture as though a set of ideal batch equilibrium reactors were aligned in series in which the products from one equilibrium stage become reactants for the next reactor. After all the reactions have been completed, products from the last reactor are recycled to the first reactor, and the reaction sequence is repeated. Equilibrium of all components is complete when the product compositions at the end of two consecutive cycles are identical. The method compares favorably with the free energy minimization technique and is useful for changing conditions or input parameters. 

Because hydrolytic reactions are reversible, they are seldom carried out in batch wise processes [26,28,36,70]. The reactor is usually a double jacket cylindrical flask fitted with a reflux condenser, magnetic stirrer, and thermometer connected with an ultrathermostat. The catalyst is added to the reaction mixture when the desired temperature has been reached [71,72]. A nitrogen atmosphere is used when the reactants are sensitive to atmospheric oxygen [36]. Dynamic methods require more complicated, but they have been widely used in preparative work as well as in kinetic studies of hydrolysis [72-74]. The reaction usually consists of a column packed with a layer of the resin and carrying a continuous flow of the reaction mixture. The equilibrium can... 

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