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- Author or Editor: P. Selucký x
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Abstract
The optimum concentration of the extractants for rapid radiostrontium concentration is 0.1M HB (chlorinated cobalt dicarbollide acid) and 1.5% vol. of Slovafol 909 in a mixture of CCl4(40%) and nitrobenzene. The recommended initial carrier concentration is 2·10–4 M Sr, initial aq. pH4.3, time of shaking 3 min. Yield in the range 80–97% can be achieved in rapidly concentrating Sr from 1 dm3 aqueous phase into 10–20 ml of the extract. The yield decreases with increasing Ca concentration in the model water. The time needed for the concentrating does not exceed 30 min.
Abstract
A typical composition of the solvent extraction system suitable for a rapid separation (3 min shaking) of Ca and Sr (separation factors
5000) in both tracer and macroconcentrations involves: organic phase–0.11M Li-dicarbollide and 1.65% Slovafol 909 in a mixture of 40% vol. CCl4 and 60% nitrobenzene; aqueous phase–0.15M EDTA, 0.1M (H, Li)Ac (acetate buffer), pH
5.2. Replacing Slovafol 909 (suitable for the preconcentration of RdSr) by polyethylene glycol 400 enhances the distribution ratioD
Sr by a factor of 7 and
by a factor of 2. Using Na salts instead of Li ones IowersD
Sr by a factor of
100 and does not affect the
value. When separating macroamounts of Ca from Sr traces, care must be exercised to ensure the desired pH value and free EDTA concentration.
Abstract
Abstract
Abstract
Extraction of microamounts of calcium and strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of polypropylene glycol PPG 425 (L) has been investigated. The equilibrium data have been explained assuming that the species HL+, CaL2+ and SrL2+ (L = PPG 425) are extracted into the organic phase. The values of extraction and stability constants of the cationic complex species in nitrobenzene saturated with water have been determined. It was found that in water-saturated nitrobenzene, the stability constant of the complex SrL2+, where L is PPG 425, is somewhat higher than that of the species CaL2+ with the same ligand L.
Abstract
Extraction of microamounts of calcium, strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of dibenzo-18-crown-6 (DB18C6, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, ML2+, ML2 2+ and MHL2 3+ (M2+ = Ca2+, Sr2+, Ba2+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.
Abstract
Abstract
Extraction of microamounts of cesium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of polypropylene glycol PPG 425 (L) has been investigated. The equilibrium data have been explained assuming that the complex species HL+ and CsL+ (L = PPG 425) are extracted into the organic phase. The values of extraction and stability constants of the cationic complex species in nitrobenzene saturated with water have been determined.
Abstract
Extraction of microamounts of cesium by a phenyltrifluoromethyl sulfone (FS 13) solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of polyethylene glycol PEG 400 (L) has been investigated. The equilibrium data have been explained assuming that the species HL+ and CsL+ (L = PEG 400) are extracted into the organic phase. The values of extraction and stability constants of the cationic complex species in FS 13 saturated with water have been determined.