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Abstract  

The distribution coefficients for alkali and alkaline earth metal ions on potassium cobalt hexacyanoferrate (II), K2CoFe(CN)6×1.4H2O, show high selectivity for cesium. The uptake values of the ions vary widely. The uptake is most probably an ion exchange process.

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Abstract  

57Co Mössbauer emission spectra of cobalt benzoylacetonate and 3-substituted acetyl-acetonates have been studied. All spectra reveal the same stabilized57Fe forms, though in a ratio depending on the substituent in the ligand. This dependence is interpreted in terms of the substituent effect on the nature of metal-ligand bonding.

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Abstract  

The aim of the present work was to investigate iron, cobalt and chromium distribution in samples of living and non-living matter by using instrumental neutron activation analysis (INAA). Investigations were carried out starting with water systems components, such also specias living in these systems and biological tissues from rat and human organs. The following conclusions have been drawn for elements distribution in the relation enviromment/living matter: (1) iron, cobalt and chromium contents in plankton are very close to these found in suspended materials; (2) among all the investigated living organisms, the highest contents of investigated elements have been found in fish; (3) inspite of the contents of iron, cobalt and chromium being somewhat lower in bentos and crustacea than in suspended materials, all the obtained values are very close, and (4) human liver has somewhat higher iron- and cobalt-contents than rat liver, which, however, has higher chromium concentration. Of all the investigated living organisms chromium content was the lowest in human liver.

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Abstract  

Flameless atomic absorption spectroscopy has been successfully applied to the analysis of trace levels of gold, silver and cobalt in milligram quantities of aluminum. The two-line method of background correction was used with good, but not total, success. The reproducibility of the measurements was excellent, and the results compared very well with the expected values.

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Abstract  

A solid-state phase transition in cobalt dibromide at 647 K has been revealed by three different alternative current techniques. A small thermal effect of (181±18) J mol−1 corresponding to the enthalpy of the transition has been determined by differential scanning calorimetry. The effect was observed on cooling and on heating as well.

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CoO/Al2O3 catalysts containing amounts of cobalt ranging form 2 to 20% were prepared atpH 11 from neutral mesoporous alumina composed of γ-Al2O3 and poorly crystalline boehmite, and were then dried at 80‡C. X-ray diffraction, DTA and TG techniques were used to study the structural changes produced upon thermal treatment up to 700‡C.

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Abstract  

The chloro complexes of cobalt, nickel and copper with 3-phenylpyridine were prepared in ethanolic solution from which solid compounds were isolated. The cobalt and copper complexes have stoichiometry M2LCl4 while the nickel complex has stoichiometry NiLCl2. The suggested structure for the cobalt and copper complexes is tetrahedral, while for the nickel complex it is octahedral. Thermal analysis studies show that the cobalt and copper complexes form intermediate complexes before their metal oxides are produced. The nickel complex also forms an intermediate complex and then nickel chloride before the nickel oxide is obtained.

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Abstract  

A new cobalt(II) trihydrogen hexaoxoperiodate tetrahydrate has been synthesized: CoH3IO64H2O and has been characterized by quantitative analysis, TG, DTA, DSC and IR spectroscopy. Based on DTA and DSC data, a thermal decomposition scheme has been proposed for this complex.

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Abstract  

A rapid and sensitive substoichiometric radiochemical procedure has been developed for the extraction of cobalt with potassium salts of ethyl, propyl, butyl, pentyl and benzyl xanthates. The relative extractabilities of the cobalt-xanthate complexes into chloroform and carbon tetrachloride were studied. Substoichiometric quantification methods were developed in each case and utilised to determine the cobalt content present in standard solutions as well as biological samples.

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Abstract  

The sorption of long-lived radionuclides of cesium, strontium and cobalt (134Cs, 85Sr and 60Co) on bentonite under various experimental conditions, such as contact time, pH, sorbent and sorbate concentrations have been studied. The uptake of Cs and Sr was rapid and equilibrium was reached almost instantaneously in both the cases, while Co sorption was time dependent. The sorption of these nuclides increased by increasing pH. The uptake of Cs, Sr and Co increased with increasing the amount of the bentonite clay. The percentage sorption for Cs, Sr and Co decreased with increasing metal concentrations. The desorption studies with 0.01M CaCl2 and ground water at low-metal loadings on bentonite showed that about 95% of Cs, 85-90% of Sr and 97% of Co were irreversibly sorbed. These results could be helpful for nuclear waste management, for waste water effluents containing low concentrations of cesium, strontium and cobalt.

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