Batch-type experiments

In conclusion, the maximum adsorption capacity should be measured in fixed-bed experiments under dynamic conditions, and if models are applicable, diffusion coefficients should be also determined in fixed-bed apparatus. Due to the fact that the equilibrium isotherms require extended data series and thus are time-consuming experiments, the latter are quite difficult to be conducted in fixed-bed reactors and from this point of view, it is more practical to evaluated equilibrium isotherms in batch reactor systems. Then, it is known that when applying fixed-bed models using an equilibrium isotherm obtained in batch-type experiments, the equilibrium discrepancy (if it exists) can be compensated by a different estimate for the solid diffusion coefficient (Inglezakis and Grigoropoulu, 2003 Weber and Wang, 1987). 

In order to distinguish between nonpro-tein-bound platinum and unbound cis-Pt or carbo-Pt, trichloroacetic acid (TCA) protein precipitation, or the precipitation of plasma proteins with cold ethanol and ultrafiltration, can be used (Ma et al. 1996). Other batch-type experiments were reported to study the binding behavior of Pt-compounds using ET-AAS as the determination method (Parsons et al. 2003). Gel-permeation chromatography was used to study Pt species in extracts from plants treated with Pt-salts (Messerschmidt et al. 1994), while Alt et al. (2002) studied the bonding stage of Pd in endive. 

Batch and continuous types of experiments were carried out in order to study the effect of additives upon the isomerization of n-pentane (Mavily et al., 32). Batch type experiments were carried out in a turbomixer t3T>e autoclave. Relatively small amounts of material sufficed in this type of test, which permitted a rather rapid survey of a wide variety of additives. 

Batch type experiments were conducted to understand chemical functions and reaction mechanisms related to hydro-geochemical alteration processes. Experiments were conducted for up to 26 days, over a wide temperature range... 

Numerical calculations were undertaken for systems with a water/rock ratio of 8, which was typical for our batch type experiments. If temperature conditions are set at 250, then the first precipitated mineral was Na-montmorillonite, then chalcedony and illite, which is consistent with our experimental results. Na-montmorillonite was observed in batch experiments at the same conditions, which agrees with modeling and demonstrates how Na-montmorillonite can be formed from non-marine sediment/meteoric water interaction. 

A batch type experiment led to the following data in Table 1 ... 

Batch type experiments with respect to the hydrocarbon mixture were carried out. The batch volume was around 100 ml and the catalyst weight was about 1 g. n-Hexane (inert) was used as a solvent and some quantities of propane were employed to regulate independently the total pressure and H2 partial pressure (pH2), which was kept constant during the run [5]. 

Let B be the component with highest concentration, while the most convenient way to follow reaction is by titration of A. A batch-type experiment led to the data given in Table 8.1.A-1. 

The formation of OH radicals by the reaction of alkenes and O3 in the polluted atmosphere is very important in atmospheric chemistry of ozone formation described in the next section. The yields of OH radicals under the atmospheric pressure are compiled by the lUPAC subcommittee (Atkinson et al. 2006) and summarized in Table 7.3. These values are those obtained by the batch type experiments with OH scavengers, while Kroll et al. (2001a) investigated pressure dependence (1 00 torr) of the initial OH yields in the reaction of O3 and alkene using a high-pressure flow system coupled with the direct detection of OH by LIF. From this experiment, strong pressure dependence was found for the OH formation yields from alkenes other than ethylene with the OH yields higher than unity at low... 

A sorption isotherm is completed for each solid particle type and SWMs/ COMs. A range of solid to solution concentrations (i.e., solid solution) was chosen for each solid phase and waste material leachate (e.g., 50-250 mg/l),with about five data points per range. All control and test samples were performed in duplicate. The solution used in the isotherms was prepared by a 24-h batch leaching experiment with the solid test material and distilled water. The material controls consisted of the test material leachate without the solid phase particles. Chemical analyses, expressed either as TOC or as individual organic compound (e.g., aliphatic and aromatic compounds) concentrations relative to the organic carbon content of the SWM/COM, revealed the actual concentrations of various organic constituents in the leachates. Solid phase controls were also prepared for each of the test soils/sediments in order to determine the concentrations of the constituents leached from the solid phase alone. 

Experiments were carried out in batch-type and flow-type supercritical biomass conversion systems. The batch-type reaction system was the same as reported previously (14). In brief, it consisted of a tube reaction vessel (Inconel-625 5 mL in volume) equipped with a thermocouple and a pressure gage. For hydrolysis reaction, 1 mL of rapeseed oil mixed with 4 mL of water was fully charged into the reaction vessel. The reaction vessel was then heated with molten tin preheated at desired temperatures. It took about 12 s to reach the reaction temperature. Subsequently, the vessel was moved into a water bath to quench the reaction. Reaction time was counted from the time a mixture reached the reaction temperature to when it was quenched. The obtained product was then kept for about 30 min until the two phases separated the upper portion is the hydrolyzed product, while the lower is a mixture of water and glycerol. The upper portion was then evaporated in a vacuum evaporator to remove any water. 

Rapeseed oil and its fatty acids (stearic, palmitic, oleic, linoleic, and linolenic acids) were chosen as the samples of vegetable oil. The experiments were performed in the batch- and flow-type supercritical biomass conversion systems developed in our laboratory. For the batch-type system, a reaction vessel was made of Inconel-625 with a volume of 5 mL for the flow-type system, the supercritical treatment tube was constructed from Hastelloy stainless steel (HC 276) with length of 84 m and an id of 1.2 mm, with the total volume being about 95 mL. Detailed information about the equipment can be found elsewhere (13). 

A batch microcalorimetric experiment, very similar to the one just described, is possible with a diathermal heat flowmeter type of microcalorimeter, which is less versatile than the Tian-Calvet microcalorimeter (especially in its temperature range and ultimate sensitivity), but of a simpler design. In the Montcal microcalorimeter (Partyka et al., 1989), the thermopile with up to 1000 thermocouples is replaced by a few thermistors. 

The mathematical definition of a chemical reaction rate has been a source of confusion in chemical and chemical engineering literature for many years. The origin of this confusion stems from laboratory bench-scale experiments that were carried out to obtain chettiical reaction rate data. These eai ly experiments were batch-type, in which the reaction vessel was closed and rigid consequently, the ensuing reaction took place at constant volume. The reactants were mixed together at time t - 0 and the concentration of one of the reactants, was measured at various times f. The rate of reaction was determined from the slope of a plot of as a function of time. Letting be the rate of formation of A per unit volume (e.g., g mol/s dm ), the investigators then defined and reported the chemical reaction rate as... 

The process conducted in batch-type counter-flow apparatus (Figure 30.17) equipped with capillary PP Acccurel membranes showed good effectiveness of membrane distillation for purification of radioactive waste. Permeate obtained was pure water. All solutes together with radioactive compounds were rejected by the hydrophobic membrane. At tenfold volume reduction of the initial portion of waste, approximately tenfold concentration of radioactivity in the retentate stream was reached, while radioactivity of permeate retained on the level of namral background (Figure 30.18). As was observed in experiments small sorption in the system took place. However, permeate was free of radioactive substances and other dissolved compounds, the concentration and radioactivity factors sometimes slightly differed from volume reduction factors. 

Regeneration of Zeolon-900 Column. Zeolon-900 loaded with cesium-137, which had been adsorbed from fuel basin water, was used in batch-type and column experiments to determine if the cesium could be removed by regenerating with several different reagents. The equivalent of six column volumes of regeneration solution was used for a single contact in the batch experiments. Table V shows the effectiveness of the regenerants to remove cesium-137 from the Zeolon-900 in the order of their effectiveness. 

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-... 

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