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- Author or Editor: I. García-Sosa x
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Abstract
The use of18F radionuclide in the preparation of 2-[18F]-FDG is reported.
Abstract
The sorption behaviour of cobalt and cadmium by Mexican erionite was studied at different pH values and the ion exchange isothems were determined. Sorption experiments were performed with cobalt and cadmium solutions. The cobalt, cadmium and sodium content in the aluminosilicate samples were determined by neutron activation analysis. It was found that the sorption for cadmium was higher than for cobalt, however, the selectivity for both cations was low in this zeolite.
Abstract
Many factors affect the ion exchange process in zeolites. In this work the influence of different anions such as acetate, chloride and nitrate on the ion exchange of cobalt in zeolite ZSM-5 is discussed. After the ion exchange in the presence of those anions no change was found in the zeolite structure, by X ray diffraction and IR spectroscopy. The retention of cobalt by zeolite ZSM-5 at low concentrations (from 0.001 to 0.3N) was higher when the exchange was done with cobalt nitrate and chloride. This behavior was different in the case of 1N cobalt salts, since the highest sorption uptake was found when working with cobalt acetate and its sorption was directly proportional to its concentration.
Abstract
The use of NaX zeolite, in the sorption of cobalt and cadmium from aqueous solutions has been investigated. Ion exchange experiments were performed with cobalt and cadmium solutions at various pH and concentration. The cobalt, cadmium and sodium content were determined by neutron activation analysis. It was stated that the selectivity for cadmium is higher than for cobalt.
Abstract
The sorption of cesium was studied on zeolites ZSM-5 and Y. It was found that the sorption is much higher on zeolite Y than in ZSM-5 and it depends on the crystalline network of the zeolite. It was found as well that the main uptake mechanism involved in both zeolites for cesium was ion exchange.
Abstract
The apparent diffusion coefficient of Sr2+ in natural Mexican erionite from Sonora at different pH and concentrations were determined. Neutron activation was applied to measure the sorption of strontium. The apparent diffusion coefficient values showed that the mobility of Sr2+ through the cavities of the erionite depended on the concentration of strontium and the pH of the solution. As a consequence the sorption of this ion by the erionite was affected by these parameters and the maximum sorption of Sr2+ was at pH higher than 3 and 0.0094 mol·l–1 strontium nitrate solution.
Abstract
The sorption behavior of cobalt and cadmium by zeolite Y has been investigated. Cobalt and cadmium solutions were exchanged with the zeolite at different pH's. Cobalt, cadmium and sodium in the samples were determined by neutron activation analysis. The sorption of cadmium was higher than that of cobalt, however, the selectivity for both cations by the zeolite was low.
Abstract
The sorption behavior of cobalt by zeolite ZSM-5 was studied. Parameters such as temperature, hydration of the zeolite (before the sorption), as well as the presence and absence of ethylenediamine during the ion exchange at room temperature and 80 °C were considered. The highest retention of cobalt was found when the sorption experiments were done at 80 °C in the presence of ethylenediamine.
Abstract
The preparation and characterization of a Mexican organo clinoptilolite-heulandite mineral as well as the evaluation of its sorption properties for cadmium and cobalt are presented. The mineral was modified with different concentrations of hexadecyltrimethyl-ammonium bromide (HDTMA), the resulting materials were characterized by electron microscopy, IR spectroscopy, BET surface analysis, X-ray diffraction and their cation exchange capacities were determined. The cobalt and cadmium uptake was carried out in different concentrations. Neutron activation was used to measure the sorption of cobalt and cadmium. Organo zeolitic mineral samples were obtained with different surface characteristics compared with the original material and it was found that the retention of cobalt and cadmium by the organo zeolite diminishes due to the presence of HDTMA.
