Cation surface-inactive

The separation of surface-inactive cations can be interpreted analogously. In this case, lipophilic anions are adsorbed at the resin surface, while the analyte cations are retained in the outer region of the double layer. 

The combination of Eqs. (13), (14), and (17) make it possible to calculate the dependencies of F and F+ on o from the experimental y. E-curves. Figure 3 shows the corresponding dependencies of FF and FF+ on Eq for 0.1 M solutions of surface-inactive and surface-active electrolytes. The positive adsorption of cations at Eo < 0 and of anions at Eo > 0 in a former solution are induced only by the coulombic attraction of ions to the oppositely charged electrode surface. In contrast, the negative adsorption of cations at >0 and of anions atEo <0 is caused... 

If we suppose that cations in solutions of lithium, sodium, and potassium salts are surface-inactive, that is, at any given Eo, their surface excesses are located in... 

For nonsymmetrical surface-inactive electrolytes, the minimum of C shifts from the pzc. If, in the absolute magnitude the anion charge is higher than the cation charge, the minimum shifts from pzc to more negative values, and vice versa. Specific adsorption of ions also induces a shift of the capacitance minimum from the pzc. Moreover, when the specific adsorption is sufficiently pronounced, no minimum appears in the C, fo Curves,... 

As an example of cationic surfactant analysis in finished products. Fig. 9-125 shows the separation of alkylbenzyl-dimethyl-ammonium compounds in a toilet cleaner. As can be seen from the respective chromatogram, this raw material basically consists of two species, the C12- and the Ci4-component. Thus, chromatographic separation is much simpler than shown above for alkyl sulfonates. Because these long-chain quaternary ammonium compounds exhibit a marked hydrophobicity, surface-inactive hydrochloric acid is used as an ion-pair reagent. 

ROH is the fatty acid nonionized molecule RO is the surface-active fatty acid anion //+ is the surface-inactive cation... 

This conclusion is in complete agreement with the experimental results. Figure 6.1 shows the S vs n dependence for different solutions, viz. for a surface-inactive electrolyte, and for solutions to which specifically adsorbed anions and cations have been added. It can be seen that the results for different solutions differ considerably. If, however, we assume, in accordance with the usual equations of the theory of slow discharge[1], that the change in overpotential at a constant concentration of H" " ions is exactly equal to the change in the local -potential (the coefficient (1 - a)/a of the ij -poten-tial is equal to unity, since a = 1/2 in the Tafel regions for the investigated solutions), the displacement of one curve with respect to the other by the difference in overpotentials enables us to... 

Termination of the process is effected by the acid polymer layer of the receiving sheet. Acting as an ion exchanger, the acid polymer forms an immobile polymeric salt with the alkah cation and returns water in place of alkah. Capture of alkaUby the polymer molecules prevents deposition of salts on the print surface. The dye developers thus become immobile and inactive as the pH of the system is reduced. 

Bacterial cell walls contain different types of negatively charged (proton-active) functional groups, such as carboxyl, hydroxyl and phosphoryl that can adsorb metal cations, and retain them by mineral nucleation. Reversed titration studies on live, inactive Shewanella putrefaciens indicate that the pH-buffering properties of these bacteria arise from the equilibrium ionization of three discrete populations of carboxyl (pKa = 5.16 0.04), phosphoryl (oKa = 7.22 0.15), and amine (/ Ka = 10.04 0.67) groups (Haas et al. 2001). These functional groups control the sorption and binding of toxic metals on bacterial cell surfaces. 

Carriers frequently are stable isotopes of the radionuclide of interest, but they need not be. Nonisotopic carriers are used in a variety of situations. Scavengers are nonisotopic carriers used in precipitations that carry/incorporate other radionuclides into their precipitates indiscriminately. For example, the precipitation of Fe (OH)3 frequently carries, quantitatively, many other cations that are absorbed on the surface of the gelatinous precipitate. Such scavengers are frequently used in chemical separations by precipitation in which a radionuclide is put in a soluble oxidation state, a scavenging precipitation is used to remove radioactive impurities, and then the nuclide is oxidized/reduced to an oxidation state where it can be precipitated. In such scavenging precipitations, holdback carriers are introduced to dilute the radionuclide atoms by inactive atoms and thus prevent them from being scavenged. 

Chiche et a/.[56] have studied the oligomerization of butene over a series of zeolite (HBeta and HZSM-5), amorphous silica alumina and mesoporous MTS-type aluminosilicates with different pores. The authors found that MTS catalyst converts selectively butenes into a mixture of branched dimers at 423 K and 1.5-2 MPa. Under the same reaction conditions, acid zeolites and amorphous silica alumina are practically inactive due to rapid deactivation caused by the accumulation of hydrocarbon residue on the catalyst surface blocking pores and active sites. The catalytic behaviour observed for the MTS catalyst was attributed to the low density of sites on their surface along with the absence of diffusional limitations due to an open porosity. This would result in a low concentration of reactive species on the surface with short residence times, and favour deprotonation and desorption of the octyl cations, thus preventing secondary reaction of the olefinic products. 

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