Sorption experiments with

The presence of solutes other than ethanol might be expected to reduce the mole fractions of ethanol and water and influence the nonideality of the ethanol-water system. However, both Williams (1983), who modelled a batch wine fermentation, and Rottenbacher (1985), in ethanol sorption experiments with yeast pellets in a fluidized bed, established that the ethanol-water-yeast system behaves as if the water and ethanol content of the pellets were a simple ethanol-water solution supported by a solid matrix which influences neither mole fractions nor activity coefficients. 

Figure 8. Percentage of initial concentrations of tracers left in solution as a function of time for the sorption experiments with the blank containers, fU O Np (k)> Pu Am (O), Cm.

From sorption experiments with the rare earths and trivalent actinides, it was found that the distribution coefficients for kaolin and attapulgite were quite different, the latter having much higher values ( 1). Therefore, the radiation damage study... 

N-hexane sorption experiments with numerous different samples showed major variations in sorption properties (capacities and rates, as shown in Table 1), some of which... 

This definition of the integral sorption differs from the one proposed by Kokes et al. (1952), who termed a sorption experiment with zero initial or final concentration the integral type. It should be noted that, in reality, no definite borderline can be drawn between the integral and differential experiments defined as above. 

The uptake of certain species by coprecipitation (the adsorbent is formed in the presence of adsorbate of interest) is usually higher than adsorption on pre-formed precipitate at otherwise identical conditions (pH, concentration of sorbate, amount of adsorbent). In many older publications, e.g. [4], the terms sorption and adsorption are used in the title and abstract, while in fact coprecipitation was studied. The term adsorption is used in the present book only when the solid phase was formed in absence of the adsorbate, and the adsorbate was added afterwards. Concentrated solutions used to precipitate sparingly soluble materials are only stable in the presence of complexing agents or at extreme pH values. Thus, the history of the system in the coprecipitation experiment on the one hand and in sorption experiment with a pre-formed adsorbent on the other is very different, and with identical final conditions, the solid phases obtained in these two experiments are not necessarily the same, even for very long equilibration times. The results of thermochemical calculations (cf. Table 2.2 and examples in Section 2.II) are of limited practical importance due to kinetic limitations. Thermodynamic data relevant to fixation of metal cations on marine Mn-Fe nodules and sediments, especially formation of complex oxides have been collected by Ruppert [5]. 

Spectroscopic and Sorption Experiments with Silver-Polymer Complexes (Section 9.2,2) [20-22]... 

The sorption experiments with Ketelmeer and Hollands Diep sediments (Figure 3) were carried out in a 10 M Ca-solution. Table I shows that the rate parameters are indeed very similar, for both models, to those for Ca-saturated illite (in the same aqueous solution). If we use the 3-box model for the best fit to the early data points, the fast reversible process (r) has a half life of a few (1-4) days. The slower, irreversible, process (k) has a half life of approximately 20-50 days. 

A low value of x indicates greater affinity between the solnte and the polymer. It is relatively easy to estimate single-component X from sorption experiments with pure solvent. For a binary mixture, similar sorption data yield the values of % These can be used to ascertain the relative sorption of the two components by a given polymer. 

To determine the helium volume of NORIT Rl, sorption experiments with helium at 298.15 K and 323.15 K were performed using a two beam microbalance (Sartorius). Results of measurement are shown in Figure 3.9. The slope of the straight lines correlating data of the apparent weight of the sample as function of the density of the helium gas (pHe), is the negative value of sorbent s helium volume (V ), cp. eq. (3.13). 

The temperature of the system was controlled to a constant value during the sorption experiments and the thermostat system kept the temperature constant within an accuracy of 0.1 K. Two different sequences of sorption experiments, with two different samples, were conducted for each penetrant at each temperature. Excellent reproducibility was obtained in all cases. The difference in solubility values obtained from repeated runs was negligible for most of the experimental conditions examined and never exceeded 5%. 

The authors repeated the experiment with two, more strongly retained, solutes m-dimethoxy benzene and benzyl acetate. These solutes were found to elute at (k ) values of 10.5 and 27.0 respectively on a silica column operated with the same mobile phase. The results obtained are shown as similar curves in Figure 13. The m dimethoxy benzene, which eluted at a (k ) of 10.5, also failed to displace any ethyl acetate from the silica gel even when more than 0.5 g of solute resided on the silica surface. Consequently, the m-dimethoxy benzene must have also interacted with the surface by a sorption process. 

In order to prove the limitation of the process by quasi-diffusion in the grain, it is most convenient to carry out experiments with phase contact interruption [107], For the sorption of organic ions after this interruption and the restoration of the contact after a certain period of time, the dependence usually the shape of... 

Another major drawback of polysaccharides is their hydrophilic nature leading to low degrees of adhesion between fiber and matrix [11]. Moisture absorption takes place by three types of mechanisms namely diffusion, capillarity, and transport via micro cracks [2]. Among the three, diffusion is considered to be the major mechanism. Water absorption largely depends on the water-soluble or hygroscopic components embedded in the matrix, which acts as a semipermeable membrane. While, fiber/matrix adhesion and fiber architecture also affect the moisture absorption. The results of the water sorption experiment showed an interesting trend. The extent of water uptake was not very significant and also did not increase linearly with amount of filler (Table-2). 

The fermentation wastes Corynebacterium glutamicum biomass) were obtained in a dried powder form from a lysine fermentation industry (BASF-Korea, Kunsan, Korea). The protonated biomass was prepared by treating the raw biomass with a 1 N HNO3 solution for 24 h, thereby replacing the natural mix of ionic species with protons. The resulting C glutamicum biomass was dried and stored in a desiccator and used as a biosorbent for the sorption experiments. 

For a classical diffusion process, Fickian is often the term used to describe the kinetics of transport. In polymer-penetrant systems where the diffusion is concentration-dependent, the term Fickian warrants clarification. The result of a sorption experiment is usually presented on a normalized time scale, i.e., by plotting M,/M versus tll2/L. This is called the reduced sorption curve. The features of the Fickian sorption process, based on Crank s extensive mathematical analysis of Eq. (3) with various functional dependencies of D(c0, are discussed in detail by Crank [5], The major characteristics are... 

The experiments of the sorption of propene in zeolite with preadsorbed CO (or in another series of experiments with preadsorbed NO) displays that propene replaced CO from Co2+ sites the band of Co2+-CO (at 2206 cm"1) diminishes as the bands of C=C—Co2+ (1590 and 1605 cm"1) increase (Figs. 1 A and B). On the other hand, the sorption of CO in zeolite with preadsorbed propene exhibits that CO is not able to replace propene the band of C=C Co2+ does not change upon the sorption of CO (spectra not shown). Contrary to CO, nitrogen monoxide was found to be able to remove propene from Co2+ sites - the bands of propene disappear upon NO sorption whereas Co2+(NO)2 dinitrosyls appear (Fig. 1 C). On the other hand, propene does not... 

Low temperature CO sorption experiments monitored with the IR spectroscopy were used to determine the nature of active (acid) sites present in the Fe-TON zeolites. It is well known that CO is a useful probe molecule for Lewis acid sites. Narrow and well resolved bands appear in the region 2135 - 2150 cm"1. The IR spectra of CO sorbed in amount sufficient to cover all Lewis sites in the Fe-TON of different Si/Fe ratios are presented in Figure 2A. The samples of a high iron content (Si/Fe=27, 36) showed a significantly lower thermal stability. The activation of the NFL form of these Fe-TON... 

Thus, either type I or type IV isotherms are obtained in sorption experiments on microporous or mesoporous materials. Of course, a material may contain both types of pores. In this case, a convolution of a type I and type IV isotherm is observed. From the amount of gas that is adsorbed in the micropores of a material, the micropore volume is directly accessible (e.g., from t plot of as plot [1]). The low-pressure part of the isotherm also contains information on the pore size distribution of a given material. Several methods have been proposed for this purpose (e.g., Horvath-Kawazoe method) but most of them give only rough estimates of the real pore sizes. Recently, nonlocal density functional theory (NLDFT) was employed to calculate model isotherms for specific materials with defined pore geometries. From such model isotherms, the calculation of more realistic pore size distributions seems to be feasible provided that appropriate model isotherms are available. The mesopore volume of a mesoporous material is also rather easy accessible. Barrett, Joyner, and Halenda (BJH) developed a method based on the Kelvin equation which allows the calculation of the mesopore size distribution and respective pore volume. Unfortunately, the BJH algorithm underestimates pore diameters, especially at... 

Laboratory sorption experiments are used to determine the distribution of a compound between the solid and liquid phases in the absence of other processes involved (e.g. biodegradation, precipitation) under controlled conditions. Sorption experiments are usually performed by adding particulate matter, free of surfactants, to solutions with different known surfactant concentrations at constant temperature (sorption isotherms). The experiments performed at high concentrations of... 

Recently, new sorption experiments have been conducted with marine sediments [30] and microalgae [31]. Specifically these experiments have... 

Frequently it is convenient, when conducting sorption experiments, to use a cosolvent such as methanol to facilitate transfer of a volatile or insoluble solute. Equation 31 may be used to estimate the effect of the cosolvent on measured sorption coefficient. If fc equals 10- and a is conservatively chosen as unity, the methanol is predicted to decrease the sorption of anthracene (ac = 9.76 log Kow = 4.54 50) by 1% relative to the case of no cosolvent. The effect of the cosolvent should be smaller for solutes with smaller HSA (or KQW), which is consistent with the observed negligible impact of methanol at f. < 10 3.6 52). ... 

Reaction kinetics. The time-development of sorption processes often has been studied in connection with models of adsorption despite the well-known injunction that kinetics data, like thermodynamic data, cannot be used to infer molecular mechanisms (19). Experience with both cationic and anionic adsorptives has shown that sorption reactions typically are rapid initially, operating on time scales of minutes or hours, then diminish in rate gradually, on time scales of days or weeks (16,20-25). This decline in rate usually is not interpreted to be homogeneous The rapid stage of sorption kinetics is described by one rate law (e.g., the Elovich equation), whereas the slow stage is described by another (e.g., an expression of first order in the adsorptive concentration). There is, however, no profound significance to be attached to this observation, since a consensus does not exist as to which rate laws should be used to model either fast or slow sorption processes (16,21,22,24). If a sorption process is initiated from a state of supersaturation with respect to one or more possible solid phases involving an adsorptive, or if the... 

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