Capacity cation

Sheldon J, Rodes B, Zouhm F, Bartholomeusz A, Soriano V (2006) Mutations affecting the reph-cation capacity of the hepatitis B virus. J Viral Hepat 13 427 34 SPREAD Programme (2008) Transmission of drug-resistant HIV-1 in Europe remains limited to... 

The anion-responsive properties of PVI-dispersed Dixon Air-Spun 200-10 were then tested against mixed acid-treated Aquadag. The result was positive, the anion capacity being comparable to the cation capacity of similar material dispersed with TA. The oxidizable iodide ion originally present in the electrode, if incompletely exchanged by chloride in the demineralization cell, would doubtless contribute something to anion responsiveness. 

A cation-responsive electrode can associate cations with chemical bonds therefore, its cation capacity is always higher than its anion capacity. In this case, the total capacity is limited solely by the anion capacity. On the other hand, the total capacity of an anion-responsive electrode is limited by its cation capacity. 

More widely used promoters for this purpose are silver zeolite and silver silicate, which were developed by Paulsen [18] and Garegg [19], respectively. Although not being commercially available, these reagents can be conveniently prepared from silver nitrate and proved to be quite powerful. More recently, van Boeckel developed the use of silver silica-alumina, which was reported to be more reactive than other insoluble salts and to have an enhanced cation capacity [20]. Representative examples of successful y0-mannosylation by using insoluble salts are depicted inO Scheme 8 [19,21,22]. 

The ion-exchange tests with organic anion salts did not verity any anion-exchange properties of the samples under study. The presence of organic anions has not been detected by IR in the treated samples. The introduction of tin results in cation-exchange properties. The cation capacity of the sample SnAlPO-0.05 was about 0.13 Cu2" /u.c. and 0.08 Co /u.c.. The respective values for sample SnAlPO-0.1 were 0.19 and 0.14. The molar contribution of Sn in unit cell of the above SnAlPO samples is 0.1 and 0.24, respectively. Thus the number of the cations introduced correlates with the tin number. The presence of cation-exchange properties proves localization of tin in the framework positions. 

Several divalent cations were also eluted with eluent containing the ethylenediam-monium- or w-phenylenediammonium 2+ cation. Capacity factors for these and other eluent are summarized in Table 5.8. It can be seen that the 2-v diamine cations are much more efficient than Mg ", Na", or H" ". 

In tailoring sorbents for rr-complexation, both the cation-sorbate bond strength and the total number of cations are important. The density of cations depends on the cation exchange capacity of the zeolite. Table 8.3 provides useful information on the total cation capacities for a number of zeolites. 

In experiments on the electrocapillary curve this effect is quite evident Philpot and Frumkin ) have given modifications of Stern s theory which take this changing capacity into account, by assuming two different anionic and cationic capacities, and a certain graduel transition between them ... 

As an adjective applied to metals base represents the opposite of noble, i.e. a base metal would be attacked by mineral acids, base exchange An old term used to describe the capacity of soils, zeolites, clays, etc. to exchange their cations (Na, K, Ca ) for an equivalent of other cations without undergoing structural change. An example of the general process of ion exchange. ... 

Figure C2.12.1. Origin of ion exchange capacity in zeolites. Since every oxygen atom contributes one negative charge to the tetrahedron incoriDorated in the framework, the silicon tetrahedron carries no net charge while the aluminium tetrahedron carries a net charge of-1 which is compensated by cations M.

AMP-1 4.0 Microcrystalline ammonium molybdo-phosphate with cation exchange capacity of 1.2 mequiv/g. Selectively adsorbs larger alkali metal ions from smaller alkali metal ions, particularly cesium. 

Carboxylate exchangers contain —COOH groups which have weak acidic properties and will only function as cation exchangers when the pH is sufficiently high (pH > 6) to permit complete dissociation of the —COOH site. Outside this range the ion exchanger can be used only at the cost of reduced capacity. 

Example Shaking 50 mL of 0.001 Af cesium salt solution with 1.0 g of a strong cation exchanger in the H-form (with a capacity of 3.0 mequiv g ) removes the following amount of cesium. The... 

Polymeric cation-exchange resins are also used in the separation of fmctose from glucose. The UOP Sarex process has employed both 2eohtic and polymeric resin adsorbents for the production of high fmctose com symp (HFCS). The operating characteristics of these two adsorbents are substantially different and have been compared in terms of fundamental characteristics such as capacity, selectivity, and adsorption kinetics (51). 

---