Solubility and some properties of aqueous solutions of fullerenol-d and composition of crystal hydrates

Method of isothermal saturation in ampules was used to study the solubility of fullerenol in distilled water in the temperature range 20–80°C and to determine the composition of its equilibrium crystal hydrates. The pycnometric technique was employed to examine how the density depends of the concentration of fullerenol solutions and the average molar and partial molar volumes of the components in solution at 25°C was calculated. The method of refractometry was used to study the dependence of the refractive index on the concentration of fullerenol solutions and the specific refraction of the solutions was calculated.     

Demineralization of Industrial Activated Carbons in an Extractor for Removing Components from Solid Materials

The possibility of exhaustive demineralization of industrial carbon sorbents by multiple treatment in the sequences acid-water-ammonia and alkali-water-acid-water was assessed. The influence exerted on the degree of demineralization by the process mode and composition of the alkaline solution was studied.     

Composite Ion Exchangers Based on KU-23 and KM-2P Cation Exchangers and Nickel(III) Hydroxide and Their Use for Purification of Nickel Sulfate Solutions To Remove Cobalt(II) Impurity

A method of preparing composite ion exchangers based on macroporous cation exchangers and nickel(III) hydroxide was developed, and their suitability for deep purification of nickel(II) sulfate solutions to remove small amounts of cobalt(II) was demonstrated.     

Relation between the structure and extracting power of higher tertiary amines

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.     

Synthesis and identification of fullerenol prepared by the direct oxidation route

A route was developed for synthesis of fullerenol, which was further identified by electron spectroscopy, infrared spectroscopy, optical microscopy, high-performance liquid chromatography, and mass spectrometry.     

Use of complexones for the extraction separation of rare earth and transplutonium elements with amines

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.     

Acid-Base Properties and Structural Features of Composite Ion Exchangers Based on KU-23 and KM-2p Cation Exchangers and Hydrated Zirconium Oxide

A method for introduction of hydrated zirconium oxide into macroporous cation exchangers KU-23 and KM-2p and the acid-base properties and structural features of the composite ion exchangers are described.     

Mutual Influence of Rare-Earth Metals(III) in Their Joint Extraction from Aqueous Solutions with a Toluene Solution of Trialkylbenzylammonium Naphthenate

Extraction of nitrates of lanthanides(III) [La(III)-Lu(III) and also yttrium(III)] from their aqueous multicomponent systems with a toluene solution of trialkylbenzylammonium naphthenate was studied at 298 K and pH 3. Physicochemical and mathematical models describing the distribution and mutual influence of lanthanides(III) [Ln(III)] in their joint extraction from multicomponent aqueous solutions as influenced by the total Ln(III) concentration in the aqueous phase and composition of their mixture was developed.     

Oscillatory extraction — New method of similar elements and isotopes separation

The new separation extraction method was created based on oscillatory extraction/stripping process in two extractors coupled by bulk liquid membrane (LM). The experimental setup to investigate the kinetics of non-stationary processes was built in Saint Petersburg State Institute of Technology in the Rare Earth Department. To induce the oscillatory extraction-stripping process the cyclic Belousov-Zhabotinsky (BZ) reaction or cyclic electrochemical oxidation-reduction was used. The possibility to use oscillatory extraction approach to separate similar elements by using the differences in their kinetic properties is demonstrated. The experimental evidences of uranium, cerium and neodymium isotopes separation were obtained. The separation of ¹⁴²Ce and ¹⁴⁰Ce isotopes between aqueous phases of two extractors coupled by bulk LM in the experiments with cyclic chemical oxidation/reduction with enrichment factor about 2.5% was observed. Under the same conditions the separation of the Nd isotopes (heavy isotopes of Nd — ¹⁴⁴Nd, ¹⁴⁵Nd, ¹⁴⁶Nd, ¹⁴⁸Nd, and ¹⁵⁰Nd from the light isotope — ¹⁴³Nd) in the same experiment with enrichment factor about 0.7–1.4% was observed.     

Mathematical model of ree separation using heat oscillating extraction

The influence of periodical oscillations of the temperature on extraction and stripping processes in the extraction systems is studied. Two extraction system were investigated, No.1: 6M NaNO₃ — Nd(NO₃)₃ — Pr(NO₃)₃ — TBP — kerosene and No. 2: [Nd(NO₃)₃·3TBP] — [Pr(NO₃)₃·3TBP] — kerosene — 0.1M HNO₃. Mathematical model of the non-stationary membrane extraction is presented including the dependence of extraction rate constants on temperature. The values of activation energy for direct and reverse reactions of extraction and stripping reactions of Pr and Nd were calculated from experimental time dependencies of metal concentrations and temperature by solving reverse kinetics problem using the proposed mathematical model. Series of experiments with the effect of periodical temperature oscillations on the extraction system for separation of rare earth elements using bulk liquid membrane between two extractors were made. The mathematical model describes experimental data adequately. On the basis of the extraction rate constants and activation energies the optimization of the extraction process of separation of rare earth elements by liquid membrane under the effect of periodical temperature oscillations has been carried out. The optimal conditions of separation by liquid membrane were found: frequency and amplitude of thermal oscillations, liquid membrane flow rate and optimal ratio between organic and aqueous phase in the extractors.