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- Author or Editor: V. Shvedov x
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Abstract
A scheme of fractionation of210Pb,210Bi,210Po forms present in air aerosols based on the combination of methods of radiochemical analysis and radiometric deteemination with leaching by different agents has been developed. The ratio between the210Pb,210Bi,210Po present in the aerosol samples was determined experimentally. Carbonate of210Pb, and210Po and210Bi forms connected with oxides prevai in the aerosol component of atmospheric air.
Electrofocusing of inorganic ions
Principle and general theory
Abstract
The mechanism of formation of apH gradient along a paper strip is discussed, and an equation has been derived making possible the calculation of thepH along the carrier. An equation is given relating thepH and the place of ion focusing to the stability constant. The distances between the focused zones have been estimated for the system Fe−Sr−Y, and the results are compared with the experimental data.
Relation between the structure and extracting power of higher tertiary amines
I. The extraction of nitric acid
Abstract
The effect of the composition and structure of higher tertiary amines on their efficiency in extracting nitric acid has been examined. The ionization constants of the amines in methanol have been determined by potentiometric titration. The extraction constants for nitric acid have been determined at constant ionic strength in the aqueous phase (μ=1). The dependence of these constants upon the concentrations and the degree of association of the amine salts in the organic phase has been examined. For the cases in which the role of steric factors is negligible it has been shown that at low amine salt concentrations in the organic phase there are quantitative regularities between the ionization constants of the amines in methanol, their extraction constants for nitric acid and the inductive effects of the substituents on the nitrogen atom.
Abstract
The extraction of microquantities of rare earth elements (REE) by methyl-n-diheptylamine solution in mesitylene, p-xylene, toluene, benzene and nitrobenzene has been examined. The parameter measuring the solvation of extractant in aqueous and organic phases has been suggested to describe quantitatively the influence of diluents on the extraction of REE. It was found that in spite of the considerable influence of diluents under investigation on the extraction of REE by methyl-n-diheptylamine nitrate the stoichiometry of the extracting reactions of these elements has been the same for all diluents. It has been shown that in general the consideration of the interaction of the extractant and diluents only is not sufficient to explain the regularities of their influence on the efficiency of the separation of REE nitrates.
Relation between the structure and extracting power of higher tertiary amines
II. The extraction of rare earth elements
Abstract
The effect of the structure of some tertiary amines on the processes of the separation of cerium and neodymium nitrates by extraction has been examined. It was found that the changes in extracting power of these amines owing to their different structures can not be explained by only the inductive effects of the substituents on the nitrogen atom. The steric factors in extraction of rare earth elements (REE) by tertiary amines are of primary importance, the extraction mechanism of these elements vary with the change of the amine structure. It has been shown that the methyldialkylamines are the most effective extractants among the investigated amines for both the extraction and the separation of REE. This can be explained by the considerable reduction of the hydrocarbon part of the molecules of these extractants and by the consequent change of the extracting mechanism.
Abstract
The extraction distribution and separation of rare earth elements and americium from the concentrated lithium nitrate solution with solutions of tertiary amines in organic solvents has been studied as a function of the composition and structure of complexones of the polyaminepolyacetic acid series by a radioactive tracer method. It has been found that diethylenetriaminepentaacetic acid is suitable for the separation of REE from americium(III). The apparent stability constants for the lanthanide complexes with EDTA and DTPA in concentrated litium nitrate solutions have been obtained by extraction, pH-metric titration and solubility. Using these constants, the optimum conditions of separation have been found and the separation factors of REE calculated. The calculated and experimental values are in good agreement. The optimum conditions for the separation of americium(III) from REE in a wide range of lanthanide and complexone concentrations (10−1–10−6 M) have been determined.
