Ion exchange procedures

J. X. Khym, Analytical Ion-Exchange Procedures in Chemistry and Biology, Prentice-Hall, Englewood Cliffs, NJ, 1974. 

The sizes of the voids decrease in order Cs, Rb, Na, K These differences are ascribed to the different influence of cation on the surrounding reactive species that changes the nature of alkali cation - aluminosilicate anion complexes. On the other hand, in the case that the cations are introduced in the matrix by ion exchange, (procedure b) the r3 lifetimes are approximately the same for all the cations (Table 2) and the size of cation does not have such pronounced influence. The calculated radii are shown in Table 4. 

The synthesis procedure led to a highly crystalline MCM-22 zeolite, as indicated by XRD data (Fig. 1A, a). The introduction of platinum by ion exchange procedure does not modify the crystallinity of the zeolite (Fig. 1A, b). SEM micrographs show that the sample obtained in static hydrothermal conditions is characterized by the presence of homogeneous round-shaped particles of ca. 10 pm in diameter formed by aggregation of lamellar particles [7,8], The morphology of the zeolite is not modified after platinum introduction (Fig. IB). 

The parent NH4ZSM-5 (Zeolyst, Si A 1=15) was treated with a 0.1 M Co(N03)2 at room temperature. The ion exchange procedure was repeated three times and then the precipitate was washed with water and dried at 380 K. The cobalt content corresponded to Co/Al = 0.18. We used also MgZSM-5 (Mg/Al = 0.10) obtained by the treatment of NH4ZSM-5 with Mg(N03)2 solution. Propene (MERCK 99 %), as well as carbon monoxide, and nitrogen monoxide (Linde Gas Polska 99.95%, and 99.5% resp.) were used as adsorbates. 

The template was removed by calcination in dry air at 480°C for 8 h. The calcined samples were subsequently converted to the ammonium form by an ion-exchange procedure with NH4NO3 (IN) solution at 60°C for 24 h. 

In spite of the nominal absence of Bronsted acid sites, it is possible to introduce copper species in the S-l matrix by following an ion-exchange procedure. The unit cell of the S-l can be written as follow [1] ... 

A closer inspection of the adsorption-desorption N2 isotherm at 77 K for S-l sample, before and after introducing Cu2+ ions by standard ion-exchange procedure, supported... 

Table 5.6 compares the ICP-AES results with data generated for the same sample by two other independent methods - isotope dilution spark source mass spectrometry (IDSSMS), and graphite furnace atomic absorption spectrometry (GFAAS). The IDSSMS method also uses 25-fold preconcentration of the metals and matrix separation using the ion exchange procedure, following isotope... 

Cations other than Li+ can be introduced into the film by a simple ion-exchange procedure, and this may be a simple method for obtaining multilayered structures with any cation. Organic cations, e.g., cyanine dyes, can also be introduced into the film by this procedure. Perhaps this approach for the application of highly ordered thin LB films onto the surface of electrodes could yield some new results, such an improvement in response time, as was discussed in Section 7.3.7. 

Demonstration of the feasibility and efficiency of reactive ion exchange procedures for the detoxification of carbamates. 

Guzzo, P.R., Ion Exchange Procedures, Technical Reports, Vol. 1, No 5, Albany Molecular Research, Inc. (1997)... 

Newly fermented wines are usually supersaturated with potassium bitartrate. Wineries routinely remove the excess potassium bitartrate in wines by refrigeration or ion exchange procedures. These steps are necessary to obtain a wine free of tartrate deposits after bottling. Calcium may also combine with tartrates which contribute to the deposits in wines. Generally, the stabilization practices for potassium bitartrate are sufficient to remove calcium tartrate from wines. 

When the Claviceps strain SD 58 was grown in a culture medium containing saccharose the slow formation of alkaloids containing polar groups was observed (15). These could not be extracted from the water phase in either alkaline or acid medium by the usual solvents. Finally, the principal alkaloid was isolated by ion exchange procedures and purified by subsequent chromatographic methods. The alkaloid was identified as elymoclavine-O-jS-D-fructofuranoside (12 ... 

Although boronium salts are most usually formed as iodides, other anions have been incorporated through metathesis reactions and ion exchange procedures in appropriate solvents. Examples of anions used are listed in Table 4. 

The starting ruthenium exchange solution is somewhat acidic, possessing a pH of 3.2. Due to the instability of Ru(H20)6 + in aqueous solution (7), the pH of the solution quickly drops to a pH of 1.26. In order to test whether the lattice destruction was simply due to the pH of the exchange solutions, the ion-exchange procedure was repeated with solutions containing no ruthenium whose pH were adjusted to 1.26 and 3.2 using HC1. 

The ion exchange column separates not only uranium from thorium but a number of other elements. What advantage(s) do you see in the ion exchange procedure relative to the precipitation or the extraction procedure If you were designing a separation scheme, which of the method would you use Why ... 

The ion exchange procedure was evaluated in several industrial environments by collecting personal, area, and stack samples. The data shown in Table XIII are the results obtained from area and personal monitoring. These results indicate that the method is indeed capable of determining MIC in the occupational environment. 

P. Pohl, B. Prusisz B, Pre-concentration of Cd, Co, Cu, Ni, and Zn using different off-line ion exchange procedures followed by the inductively coupled plasma atomic emission spectrometric detection, Anal. Chim. Acta, 502 (2004), 83-90. 

The catalyst was prepared by Johnson Matthey Chemicals pic by an ion-exchange procedure, using SORBOSIL grade AQ U30 silica as support and Pt(NH3)4Cl2 as the source of metal it was reduced in... 

The authors showed that during treatment in helium at 773 K, all of the Cu(H) was reduced to Cu(I). They concluded that mononuclear Cu(II) entered the zeolite during the ion-exchange procedure and that a mixture of Cu(I) monomers and Cu(I) pairs were formed during the dehydration in helium. During NO decomposition at 773 K, Cu(I) was partly oxidized to Cu(II). Concomitantly, an increase in the Cu-O coordination number from 2.3 to 3.4 was observed (Table 7). With additional information from... 

A small flow of 2M NaN03 was routinely introduced to the bottom of the WE-1 Column to scrub aluminum, iron, and other metallic contaminants from the DBBP phase. Even so, americium in the SIP stream is extensively contaminated with plutonium, aluminum, iron and other metallic impurities. Ion exchange procedures, both simple load-elute and chromatographic, are used to yield highly purified 2lflAm. 

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