Batch equilibrium method determination

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],... 

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... 

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. 

The adsorption equilibrium results determined by the present HPLC technique are compared with those measured by the conventional batch method and good agreement is found between the two methods. 

Example 4.2 used the method of false transients to solve a steady-state reactor design problem. The method can also be used to find the equilibrium concentrations resulting from a set of batch chemical reactions. To do this, formulate the ODEs for a batch reactor and integrate until the concentrations stop changing. This is illustrated in Problem 4.6(b). Section 11.1.1 shows how the method of false transients can be used to determine physical or chemical equilibria in multiphase systems. 

In principle, Equation (7.28) is determined by equating the rates of the forward and reverse reactions. In practice, the usual method for determining Kkinetic is to run batch reactions to completion. If different starting concentrations give the same value for Kkinetic, the functional form for Equation (7.28) is justified. Values for chemical equilibrium constants are routinely reported in the literature for specific reactions but are seldom compiled because they are hard to generalize. 

Complex stability constants are most often determined by pH-potentiometric titration of the ligand in the presence and absence of the metal ion.100 This method works well when equilibrium is reached rapidly (within a few minutes), which is usually the case for linear ligands. For macrocyclic compounds, such as DOTA and its derivatives, complex formation is very slow, especially for low pH values where the formation is not complete, therefore a batch method is... 

A review of the commonly used experimental methods for solubility determinations is presented in Table 1. Briefly, batch equilibration is the conventional method of preparing saturated solutions for solubility determinations, where an excess amount of solute chemical is added to water and equilibrium is achieved... 

Ordinarily water content may be determined by a Karl Fischer titration, but for the low concentrations in aliphatic hydrocarbons this method is filled with difficulties. To obtain even modest accuracy such as 5 ppm at HtO levels about or below 30 ppm as specified by the German Standard DIN S1777 relatively large eluent volumes (>2001 ) are required. On the other hand, the absolute and relative retentions are sensitive to 1 to 2 ppm of water consequently, two different batches of eluent with identical water content according to the above mentioned Karl Fischer titration can yield different retention values. Therefore, it is impossible to use titration as the sole method for eluent standardization. The reproducibility of adsorption chromatography, however, can be increased by continuously recycling a sufficiently lapge volume in a closed system to maintain equilibrium. 

As we have seen, the HPLC determination of MIP selectivity is of limited value. The question naturally arises as to whether a better method is available. Since this is not the subject of this chapter, we mention only briefly that batch distribution measurements of the template (or of any other substance, separately or in mixture) appear to be useful due to the equilibrium nature of the batch method. The correct... 

The calcination of BPH to BA was carried out in a batch calcinator (thermolyne 6000 furnace) which is heated to a predetermined calcination temperature (Fig. 1). During constant temperature experiments, particles were fed into the calcinator, which was in thermal equilibrium at the experimental temperature. At a predetermined time interval, samples were withdrawn using a vacuum sampling tube. Titri-metric method was used to determine the Na2B4C>7 content of sample [10]. The Ca2+ content of samples was determined by Jenway PFP 7 model flame photometer. Bulk density of BA was measured by a standard method [11]. 

Batch method A known amount of adsorbent VadS is added to a solution of the volume V containing the solute with the concentration co i. The mixture is then agitated in a closed vessel until equilibrium is reached. The final concentration in the solution (Cgqi) is determined by standard analytical methods. From the following mass balance the appropriate equilibrium loading, g(ceq), is calculated ... 

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