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- Author or Editor: P. Rajec x
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Abstract
Th anionic micellar system of the sodium dodecylsulphate (SDS) with di-2-ethylhexylphosphoric acid (D2EHPA) chelating ligand reagent in acctate buffer solutions was studied. The influence of the concentration and the composition of the micellar system for strontium preconcentration was determined. Different pH values of solutions as well as different concentration ratios of the ligand to the surfactant were used.
Abstract
Speciation of fission products (90Sr,99Tc,137Cs and152Eu) in raw cow milk was studied using the high-performance size exclusion radiochromatography (HP-SERC) by Biosep-SEC-S® column (Phenomenex, USA). The separation fraction were identified by a UV detector (280 nm) and a scintillation radiodetector. The mobile phase was Jenness-Koops buffer that simulated milk serum. Radiocesium was present only in non-protein fractions. The non-protein fractions complexed 17% of technetium and 57% of strontium. About 32% of strontium and 24% of europium were bound on the high molecular weight proteins (micellar casein). Low molecular weight proteins bound about 11% of strontium and 76% of europium. Non-size effects play a dominant role at HPSERC speciation of technetium, 83% of which follow the lightest fractions of milk.
Abstract
The properties of a composite ion exchanger containing potassium nickel ferrocyanide incorporated in silica gel matrix are described. The sorbent was prepared in the form of spherical beads. For the characterisation of the ion exchanger X-ray diffraction, electron microscopy, IR and Mössbauer spectrometry were used. The sorbent was used for the sorption of radiocesium from model solutions as well as from radioactive waste solutions (NPP Jaslovské Bohunice, Slovakia).
Abstract
The liquid membrane extraction (MX) and the solvent extraction (SX) of pertechnetate with Aliquat 336 as a carrier has been studied. From the results of SX the percentage of pertechnetate in the inner solution in experiment with LM was proposed. It has been found that the pertraction of pertechnetate depends on the inner solution used and the most effective solutions were those with ClO 4 – and SCN–. Effects of the carrier concentration in membranes and outer phase composition have been studied too. The results of these experiments were kinetic curves with a minimum, which may be interpreted as a result of competing processes in the systems.
Abstract
The development of a rapid and reproducible method for the separation of plutonium from soil samples is described. Tetravalent plutonium is extracted from 8M HNO3 into 30% Aliquat-336/toluene mixture. Uranium and thorium are removed with nitric and hydrochloric acid washes. Plutonium is backextracted with HCl–H2C2O4 and HCl–HF solutions. Plutonium is coprecipitated with NdF3 and filtrated onto a 0.1–0.2 
m membrane filter to prepare a source for 
-spectrometry. The chemical yields of separation are about 50–60%.
Abstract
With the aim of studying the effects of volume ratios and composition of the organic phase on the total yields of the main degradation products of tributyl phosphate (TBP) radiolysis, the following two-phase systems were used: water-TBP-carbon tetrachloride and water-TBP-n-alkane with various ratio of TBP in the organic phase and various volume ratios of organic-aqueous phases. We examined the influence of the distribution of two-phase systems components-precursors of radiolytic products on the total yields of the main radiolytic products and mechanism involved.
Abstract
The rate of pertraction of Sr2+ by 18-crown-6 (18-C-6) ether and picric acid in bulk liquid membrane systems containing various surface-active substances depends not only on the concentration of 18-C-6 and picric acid but also on the presence of various surface-active substances.
Abstract
Aphrons containing di-(2-ethylhexyl)phosphoric acid (DEHPA) as an active substance were used for preconcentration of strontium from acetate buffers. Conditions for preparation of reasonably stable aphrons using non-ionic and anionic detergents in n-alkane and water mixture were found. After distribution of strontium, aphrons were separated from water solution by filtration with micro-filters. The separation efficiency was compared to the results obtained in liquid-liquid extraction of strontium with DEHPA in n-alkane. The results show that the preconcentration efficiency for strontium for aphrons is as good as for liquid-liquid extraction systems.
Abstract
The transport of metal ions (Ca2+, Sr2+, Ba2+, Na+, K+, Cs+) through hollow fiber supported dichlorobenzene liquid membrane has been studied. The transport of cations using 8-crown-6 ether as a carrier and picrate as co-counter ion as well as a pertraction device and capillary isotachophoresis (ITP) measurement of the cation concentration is described.
Abstract
The ultrafiltration preconcentration of Cd2+ using micellar extraction with 8-hydroxyquinoline (8-HQ), solubilized in anionic micelles of sodium dodecylsulphate (SDS)) were studied. The n-butanol was used as a co-surfactant. Ultrafiltration yields (R, %) on cellulose acetate membranes (wet, 20000 MW-CO) under 400 kPa pressure were determined. Distribution ratios (D) of cadmium between bulk liquid phase and micellar pseudophase were estimated. The constants (app.) for the cadmium-sodium exchange on SDS micelles surface at pH values of 4.8 and 5.3 (3.36 and 3.86, respectively) were determined. It was found, that the values of ultrafiltration yields of the cadmium (at constant concentration of 8-HQ) are influenced not only by the pH and by the concentration values, but also by the ratio of the concentrations of the metal and the anionic surfactant.
