G. I. Malofeeva

Solid-phase extraction of plutonium(IV) an americium(III) using N-benzoylphenylhydroxylamine and its derivatives

The recovery and separation of plutonium(IV) and americium(III) by solid-phase extraction (SPE) on alkylated silica gel S16 modified with N-benzoylphenylhydroxylamine (BPHA) and with its derivatives was studied. BPHA was modified by introducing into the p-position of the phenyl ring of electronactive substituents that differ in their hydrophobicity: CH3, Ph, Cl, F, and NO2. The SPE of plutonium(IV) and americium(III) was studied in the range of acidities from pH 8 to 1 M HNO3. The recovery and separation of these elements was shown to depend on the nature of the substituent, aqueous acidity, and the preparation of S16 to SPE experiments.

NEW POLYMERIC SORBENT FOR PRECONCENTRATION OF METALS

Sorption properties of new aminocarboxylic polymer POLAC-1 with respect to a wide range of metals have been studied. The characteristics obtained are compared with similar ones for Dowex A-1 and Chelex 100 under static and dynamic conditions. With POLAC-1 used, the metal distribution coefficients are as high as 1·105 and more. This makes it possible to reduce column dimensions considerably, improve the solution throughput rate and concentration factors reached. Due to good sorption characteristics POLAC-1 can be recommended for wide multiple use.

Solid-phase extraction of plutonium in various oxidation states from simulated groundwater using N-benzoylphenylhydroxylamine

Solid-phase extraction of plutonium in different individual and mixed oxidation states from simulated groundwater (pH 8.5) was studied. The extraction of plutonium species was carried out in a dynamic mode using DIAPAK C16 cartridges modified by N-benzoylphenylhydroxylamine (BPHA). It was shown that the extent of recovery depends on the oxidation state of plutonium. The extraction of Pu(IV) was at the level of 98–99% regardless of the volume and flow-rate of the sample solution. Pu(V) was extracted by 90–95% and 75–80% from 10- and 100-mL aliquots of the samples, respectively, whereas the extraction of Pu(VI) did not exceed 45–50%. An equimolar mixture of Pu(IV), Pu(V), and Pu(VI) was extracted by 74%. The distribution coefficients (Kd) and kinetic exchange capacities (S) of plutonium in various oxidation states were measured. It was found that during the sorption process, Pu(V) was reduced to Pu(IV) by 80–90% after an hour-long contact with the solid phase. Pu(VI) is reduced to Pu(V) by 34% and to Pu(IV) by 55%. In the case of mixed-valent solution of plutonium, only Pu(V) and Pu(IV) were found in the effluents.

Luminescence determination of trace neptunium in natural waters with the separation of iron as a quencher

A method is proposed for the luminescence determination of neptunium in natural waters with the removal of interfering iron. For the separation of iron ionic and colloidal species, solid-phase extraction with N-benzoyl-phenylhydroxylamine as a complexing reagent is used. The method makes possible the reduction of iron concentration in samples by more than two orders of magnitude without noticeable losses of neptunium and, therefore, the attainment of a detection limit for neptunium equal to its value in samples containing no iron.

Recovery of Np(V), Pu(IV), and Am(III) by solid-phase extraction with supported N-benzoylphenylhydroxylamine

Recovery of Np(V), Pu(IV), and Am(III) by solid-phase extraction with supported N-benzoylphenylhydroxylamine (BPHA) from simulated groundwater with pH 8.5 was studied. DIAPAK C16 cartridges modified with BPHA can be used for preconcentration of these elements from natural waters by solid-phase extraction.

Preconcentration of Cesium, Cerium, Cobalt, Bismuth, and Lead Radionuclides by Solid-Phase Extraction

A procedure was proposed for the preconcentration of Sr, Cs, Pb, Co, Bi, and Ce beta radionuclides by solid-phase extraction as ion-pair complexes in the system dicyclohexyl-18-crown-6–sodium dodecyl sulfonate.

Chemical Mechanisms of Liquid–Liquid and Solid-Phase Extraction of Metal Chelates

Conditions of the liquid–liquid and solid-phase extraction of metal chelates are compared. The analogy and differences in the behavior of chelates and the effect of stability and partition constants on the completeness of the extraction of metals are discussed.

Solid-Phase Extraction of Eu(III) and Am(III) with Synergistic Mixtures of Extractants

Solid-phase extraction (SPE) of Eu(III) and Am(III) in systems containing a chelating agent and a neutral electron-donor compound was studied. In the systems 1-phenyl-3-methyl-4-benzoylpyrazol-5-one-tetraphenylmethylenediphosphine dioxide and 1-phenyl-3-methyl-4-benzoylpyrazol-5-one-trioctylphosphine oxide, the distribution factors of Eu(III) and Am(III) showed a synergistic effect owing to adduct formation.