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- Author or Editor: P. Rajec x
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Abstract
A capillary isotachophoresis was used for determination of ionogenic radiolytic products of two-phase tributylphosphate—water systems. Optimum operating conditions for analytical determination of dibutylphosphate (DPP), monobutylphosphate (MBP), H3PO4, formic, acetic, propionic and butyric acid were found.
Abstract
The specific phenomena accompanying the daughter nuclide formation by radioactive β-decay of complex parent compounds cause certain deviations from a thermodynamic distribution of daughter elements in separation procedures (e.g. in radionuclidic generators) and they are shown to complicate or, less probably, simplify their separation. A simple kinetic model has been proposed to explain such processes as the distribution of some daughter nuclides of fission products by solvent extraction with chelating compounds (systems of99Mo−99mTc and144Ce−144Pr with oxines).
Abstract
Transport of strontium through supported hollow fiber dichlorobenzene liquid membranes has been studied. The possible mechanism of strontium transport with 18-crown-6 ether as a carrier and picrate as co-counter-ion as well as the construction of a pertraction device with on-line radiometric detection of strontium using85Sr tracer is described. Preliminary results of strontium pertraction in a recycling and one-pass mode with different concentrations of crown are shown.
Abstract
The preconcentration of cadmium from aqueous colloid solution containing 8-hydroxyquinoline as extractant, laurylsulphate natrium as surfactant,n-butanol as co-surfactant was performed using micellar ultrafiltration technique. Filters with different pore size and materials were used to achieve a separation from liquid solutions. The cadmium recoveries depending on different conditions (pH, concentration of surfactant) were determined and the results are explained in the terms of colloidal parameters in the compare with the classical solvent extraction.
Abstract
It was found that the main ionogenic radiolytical degradation products of tributylphosphate were monobutylphosphate dibutylphosphate, phosphoric acid, formic, acetic, propionic and butyric acids as the result of gamma-irradiation of two-phase water-tributylphosphate system. In the case of irradiation of two-phase water-di(2-ethylhexyl)-phosphoric acid system, the main radiolytic degradation products are 2-ethylhexylphosphoric acid and phosphoric acid. All products were determined using isotachophoresis. According two-phase theory the total and partial radiation yields of products were calculated from the results.
Abstract
The main ionogenic radiolytical degradation products are monobutylphosphate, phosphoric acid, formic, acetic, propionic and butyric acids as the result of gamma-irradiation of two-phase water-dibutylphosphate system. The products were determined using capillary isotachophoresis. According two-phase theory the total (T G(X)) and partial (GI(X) for aqueous phase and GII(X) for organic phase) radiation yields of products and decomposition of DBP in the radiolysis of two phase water-dibutylphosphate systems were calculated from the results.
Abstract
Lead as well as strontium form low solubility compounds of composition (ML2)2A·nH2O, (M=Pb2+, Sr2+), in the presence of 15-crown-5 (L) and tungstosilicic acid (H4A) in acid media as found by radiometric precipitation titration. “Sandwich” structure of crown-ether complexes of lead and strontium could be expected due to the small size of cavity of 15-crown-5. Coprecipitation of PbL2/su2+ with crown complexes of strontium cation after adding tungstosilicic acid was studied in 0.01 mol·dm−3 HNO3. A significant influence of H+ cation in 1 mol·dm−3 HNO3 on coprecipitation of lead was observed. Formation of HL+ complexes by protonisation of 15-crown-5 competes to the formation of ML2 2+ complexes (approximately twenty percent of 15-crown-5 are used for creation of HL+ complexes). Formation of low solubility salts was utilised for separation of lead from strontium in 0.01 mol·dm−3 HNO3. The ratio of constant stability of lead and strontium β‘ with 15-crown-5 in 0.01 mol·dm−3 HNO3 was calculated. The separation factor S(Pb/Sr) depends on the ratio of stability constants βPbL2/βSrL2 The precipitation method can be used for separation of metals with high constant stability with crown ethers from solutions containing other metals in the case of gradual addition of crown.
Abstract
Sorption of macroamounts of the technetium thiourea complex cation by a cation exchange resin was studied in HNO3 and HClO4 solutions as a function of the concentration and reaction time for pertechnetate with thiourea. The distribution ratio reaches the value of 103 and may be even higher (>104) when sorption proceeds from a solution of the solid complex in dilute perchloric acid. The complex cation is extracted from 0.25–1M HNO3 with solutions of the bis(1,2-dicarbollyl)cobalt(III) anion in nitrobenzene—chloroform (1:1), log D=2.75−2.95 being obtained. The preconcentration and separation of technetium on cation exchangers from dilute mineral acids would seem to be one field of application.
Abstract
14C releases in the stack air of the NPPs V1 and V2, Jaslovske Bohunice was determined during the year 2004–2010. Radioactivity concentration of 14C in the stack air was determined in the forms of inorganic 14CO2 and 14C n H m . The annual average activity concentration in the stacks air samples varies between 12 and 121 Bq m−3. NPP V1, starting with 45 Bq m−3 in 2005 is decreasing due to the shutting down of the reactors (the first reactor was shut down in December 2006 and the second reactor in December 2008). The average value of radioactivity concentration for power unit V2 was 32 Bq m−3 in 2004 and reached the value of 102 Bq m−3 in the first-quarter of the 2010. The average normalized yearly discharge rates were between 0.39 and 0.64 TBq GWe −1 year−1 (2005–2008), NPP V1 and 0.19–0.61 TBq GWe −1 year−1 (2004–first-quarter 2010) for NPP V2, Jaslovske Bohunice. Most of the discharged 14C is in a hydrocarbon form, (95% for Jaslovske Bohunice NPP V2), but the CO2 fraction may reach 37% in the air stack for Jaslovske Bohunice V1.
Abstract
The use of isotope dilution technique to eliminate problems associated with demands for a high load capacity in column-coupling capillary isotachophoresis was studied. Determinations of phosphate present in a model mixture and in white wine served for the evaluation of this approach to quantitative analysis in isotachophoresis. A high selectivity of the analysis with acceptable accuracy and precision of the determination also in complex ionic mixtures in a short time are obvious advantages of this approach.
