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  • Author or Editor: M. Ganzerli-Valentini x
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Abstract  

The adsorption conditions of uranium, neptunium, thorium, europium on the adsorbers containing the benzylate salts of the 8-hydroxyquinoline (adsorber B), and of 2-methyl- 8-hydroxyquinoline (adsorber R), were prepared, supported onto charcoal and compared with an adsorber, containing the benzylic acid, (G), stabilized with d-glucoseamine, and adsorbed onto charcoal as well. Thorium, protoactinium, and europium are adsorbed nearly completely from aqueous solutions at a large pH range, even in low acid medium, whereas uranium and neptunium are completely adsorbed only from basic solutions of pH 9. The actinides are preferentially adsorbed with respect to other ions, which are present in natural waters, such as calcium or magnesium. This feature make the analysis of most actinides in natural waters easily to be performed without changing the pH of the original system. The uranium (neptunium) analysis indeed may be accomplished after adjusting the original pH to a fairly basic value (about to 9). The adsorption experiments from real samples showed that the analysis of the actinides dispersed in natural water systems may be successfully performed after previous concentration on the adsorbers prepare.

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Abstract  

Uranium and thorium were analyzed in commercial bottled waters and in fresh waters, such as tap water, by neutron activation analysis. The analysis was applied after a preconcentration step from a batch of 1–3 dm3 water under investigation. The adsorption was performed in the presence of a small amount (about 1 g) of an adsorber derived from the salt of a-hydroxyquinoline and benzilic (diphenylglycolic) acid, adsorbed onto charcoal. The preconcentration method has shown to be rapid and reliable. The overall method was set in order to have an alternative method of comparison with other different methods of analysis. The proposed method may be applied to different fresh water samples.

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Abstract  

We studied the preparation of some specific adsorbers capable of isolating and concentrating actinides. Bases of the 8-hydroxyquinoline family, diphosphineamine and tribenzylamine, salted by benzohydroxamic, benzylic or phthalic acid, are able to complex actinides in different oxidation states. As a result of the presence of the benzene rings, all the compounds are easily incorporated into active charcoal to obtain adsorbers with a highly specific surface. The adsorption behaviors of uranyl U(VI) ion, thorium(IV) and Eu(III) were studied by evaluating their distribution coefficients, K d. Results show that all the prepared salts can adsorb the ions in the III and IV oxidation state from weak acid solutions, whereas uranyl ion is adsorbed mainly from weak basic solutions. The prepared compounds can be used successfully to absorb and concentrate actinides from nearly neutral solutions, such as natural waters. The 8-hydroxyquinoline salt of the benzylic anion showed the highest adsorption values and thus seems to be the most appropriate salt to use in the analysis of actinides in water.

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Characterisation of lead rhodizonate as barium and radium adsorber from fresh water

I. Preparation and characterisation of lead rhodizonate

Journal of Radioanalytical and Nuclear Chemistry
Authors:
M. Valentini Ganzerli
,
L. Maggi
, and
V. Crespi Caramella

Abstract  

A new adsorber for concentrating barium and radium from diluted solutions and from fresh waters was prepared. It consists of basic lead rhodizhonate, namely [Pb(OH)]2C6O6·PbC6O6·H2O, supported on activated charcoal. It was named LEHRO. Preparation conditions, solubility and barium, or radium, adsorption from solutions of different pH were investigated.

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Abstract  

A procedure for90Sr determination in calcium rich samples is presented. It is based on the precipitation of calcium oxalate in homogeneous solution and under controlled conditions to minimize the coprecipitation of strontium. The latter is subsequently separated as carbonate and radiochemical purification is completed by ion exchange chromatography on two inorganic exchangers: PRTD (partially reduced tin dioxide) and CUCR (copper chromate). The procedure was applied to environmental samples such as ashed sediment, fish and vegetable and results are reported.

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Abstract  

A new inorganic exchanger consisting of the normal copper chromate (CUCR) was prepared and studied: its application to radiochemical separations was explored after batchwise measuring the distribution coefficients of several elements. Radiostrontium isolation from fission products was performed by combined use of CUCR and PRTD, a new form of tin dioxide previously investigated.

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Abstract  

A novel type of tin oxide and its cation exchange properties are described. The preparation of the oxide is rather unusual and consists in the precipitation of SnO·xH2O in the presence of sodium nitroprusside and its digestion in the presence of sodium nitrite. The final product is a partially reduced tin dioxide (PRTD) with one out of eight atoms of metal in the lower oxidation state of +2 and a great part of the bound water hydrogen replaced by sodium. Usual applications of commercially available tin dioxide exchangers can be extended to PRTD with remarkable advantages.

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Abstract  

The cobalt, nickel, zinc, selenium, rubidium and cesium content was determined in eight Italian chondritic meteorites by destructive neutron activation analysis. The chemical procedure involves only a few steps: sample dissolution, radiochemical separation of the elements on inorganic adsorbers (copper grains and zinc ferrocyanide) and on Dowex 2×8 anionic resin. Element contents are reported and discussed. Precision and accuracy of the analytical method are given as well. Results and average class values are compared with existing values in the literature. Possible correlations between pairs of elements (Co−Ni, Zn−Se and Rb−Cs) in the examined chondrites were investigated and discussed.

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Abstract  

The separation of thorium, uranium and neptunium with chromatographic columns loaded with ammonium 12-molybdophosphate (AMP) was carried out in different media with variable amounts of the elements. Columns of different sizes were used. Good separation yields were obtained, and the recovery of the elements was always greater than 95%. The use of AMP columns appears to be a useful method in the analytical chemistry of these actinide elements and it is particularly valuable in the purification and recovery of actinides in the +4 oxidation state.

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