Ion-exchangers characteristics

Dreisinger, D. B. Cooper, W. C. The Kinetics of Zinc, Ion exchange characteristics of palladium from nitric acid solution by anion exchangers. Solvent Extr. Ion Exch. 1989, 7, 335-360. 

The recent development of mixed-mode stationary phases may provide new approaches for the separation of neuroactive steroids from biological matrices. These stationary phases typically embed a charged functional group within the nonpolar carbon chains typically employed in RP separations, and as such separations based on both RP and ion-exchange characteristics can be designed. Examples of this column type are the Primesep line of columns from SIELC Technologies. This separation approach maybe quite useful for the separation of steroid sulfates from complex mixtures. 

Most gel-permeation applications have been with hydrophilic gel particles in aqueous systems, although gels have been prepared and used with organic solvents [24,25]. The gels have some weak adsorption and ion-exchange characteristics and possess the ability to retain aromatic molecules longer than non-aromatic compounds of similar molecular weight. 

The xanthate method has been used in the U.S. and Europe for a number of larger scale pilot plant studies. In the case of rayon, the technique has been explored for flameproofing, high water sorbency, ion exchange characteristics and bacteriostatic and fungistatic properties. Also nonwoven grafted fibers with excellent dispersibility for wet processing and improved binder affinities have been produced. It does not appear, however, that industrial exploitation of these technical successes will take place in the near future. 

The solid polymer electrolyte is a solid plastic material which has ion exchange characteristics that make it highly conductive to hydrogen ions. The particular material that is used for the current electrolysis cells is an analogue of TFE teflon to which sulfonic acid groups have been linked. This plastic sheet is the only electrolyte required, there are no free acidic or caustic liquids, and the only liquid used in the system is distilled water. 

The unique nature of ZSM-5 as a catalyst and as a zeolite has been well documented (L-3 ), as shown by the wide spectrum of chemistry it can catalyze as well as the wide range of morphologies and composition in which it can be synthesized. In addition, ZSM-5 exhibits ion exchange properties that, in some cases, are very different from other zeolites. Results from the study of these ion exchange characteristics have been used effectively in developing optimal methods for conversion of ZSM-5 into catalytic forms and in supplying information concerning the zeolite structure not discernible by other techniques that could lead to more active, selective and stable catalysts. 

This study has brought out some unique ion exchange characteristics of the zeolite ZSM-5. Since the catalytic characteristics and the unexpected chemistry ZSM-5 promotes are well known, these ion exchange characteristics should not be totally unexpected. It is through studies such as this as well as catalytic studies that our knowledge of this unique zeolite will increase toward a fuller tinderstanding of the overall chemistry of ZSM-5. 

Hydrous sodium titanate was prepared by the method of Dosch and Stephens (1). Titanium isopropoxide was slowly added to a 15 wt% solution of sodium hydroxide in methanol. The resulting solution was hydrolyzed by addition to 10 vol% water in acetone. The hydrolysis product is an amorphous hydrous oxide with a Na Ti ratio of 0.5 which contains, after vacuum drying at room temperature, approximately 13.5 wt% water and 2.5 wt% residual alcohol. The ion-exchange characteristics of the sodium titanate and the hydrolysis behavior of the nickel nitrate solutions were characterized using a combination of potentiometric titrations, inductively coupled plasma atomic emission (ICP) analysis of filtrates, and surface charge measurements obtained using a Matec electrosonic amplitude device. 

Ion-Exchange Behavior of Sodium Titanate. The ion-exchange characteristics of sodium titanate supports are summarized in Fig. 1 (2). In the figure, proton consumption is plotted by the solid line as the Nao.sTi is titrated from a basic pH ( 12) with HC1. Na+ (+) loss from and Cl" (-) adsorption onto the support are followed by... 

Calcium hydrosilicates compose a wide range of different compounds [26], One of them is tobermorite, Cas(0H)2Si60i5-4H20. It is an important material, since it has brilliant physicochemical properties, for example low density 0.5 g/cm, good ion exchange characteristics. In [27], tobermorite was synthesized by mechanical activation of a mixture of calcium hydroxide and silica in the presence of water at room temperature ... 

ION EXCHANGE CHARACTERISTICS OF PALLADIUM FROM A SIMULATED RADIOACTIVE LIQUID WASTE... 

In this work, batch and column experiments were carried out to investigate the ion exchange characteristics including the effects of the ionic group of ion exchangers, the concentration of nitric acid, the feed rate and also the elution characteristics of Pd(II) by various eluents for obtaining the optimal separation conditions. 

Mikhail, E.M., Ghoneimy, H.E, and Misak. N.Z., Ion exchange characteristics of ceric tungstate Cs+/H+ exchange in aqueous and methanolic solutions. Colloids Surf, 66, 231,1992. 

Ion exchange membranes include in their polymeric structure many ionizable groups. One ionic component of these groups is fixed into or retained by the polymeric matrix while the other ionic component is a mobile, replaceable ion which is electrostatically associated with the fixed component. The ability of the mobile ion to be replaced under appropriate conditions by the other ions imparts ion exchange characteristics to these materials. 

Clinoptilolite-containing tuff (CT) dust was modified by the catalytic polymerization of ethylene on the surface of CT particles. The compositions with 3-5wt.% of polyethylene (PE) and 97-95 wt.% of CT were obtained. The thin PE coating formed on the CT particles was permeable to the filtrating water solutions. As a result of encapsulation of the CT particles, the filter properties of this sorbent were improved. The ion-exchange characteristics of the modified CT (powder and pressed tablets) with respect to NH4 and Sr " cations were determined. It was shown that CT dust-PE compositions retained the ion-exchange properties of initial CT. 

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