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Abstract  

A very rapid method for the separation of molybdenum(VI) from neutron irradiated uranium and its fission products is described. The procedure is based on the selective extraction of molybdenum(VI) by a 0.1M solution of 2-hexylpyridine in benzene from 4M HCl+0.04M KSCN. Decontamination factors were estimated to be >104 for the radionuclides of niobium, zirconium, ruthenium, lanthanum, cerium, promethium, yttrium, strontium and barium.

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Selective solvent extraction of chromium(VI) using 2-hexylpyridine

Separation from uranium, thorium, fission products and first transition series elements

Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Iqbal and M. Ejaz

Abstract  

The extraction behaviour of trace and macroamounts of chromium(VI) from different mineral acid solutions by 2-hexylpyridine in chloroform has been investigated. In the chloride system, the extracted species is apparently (HPyH+)2 (Cr2O7)2− or HPy+(HCrO 4 ) for macro and trace amounts of chromium(VI), respectively. Among the common anions chloride and sulphate have little effect on extraction up to 1M concentration, while in the case of nitrate there is a continuous decrease in the extraction with the increase of salt concentration in the aqueous phase. The effect of ascorbate, acetate, citrate, oxalate, thiosulphate, thiocyanate ions on the extraction from 1M HCl was also examined. Separation factors of several elements relative to chromium(VI) have been described and the separation of chromium(IV) from a large number of elements has been achieved.

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Abstract  

The partition of tracer-level (<10−7 mole/l) platinum between various 4-(5-nonyl)-pyridine phases and aqueous nitric, hydrochloric, and sulphuric acid phases has been studied radiometrically as a function of the amine and acid concentrations. The effects of saltingout agents and some anions on the extraction of the metal are reported. The extraction data is compared with that of gold and conditions are established for the separation of daughter199Au from neutron irradiated platinum. The distribution coefficients of various metal ions are given for the 4-(5-nonyl)pyridine-10M HCl system and their factors for separation from platinum estimated.

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Abstract  

Neutron-activation analysis /NAA/ was used for the estimation of Hg, Co, Cr, Zn and Fe in leaves of various plants namelySapindus mukorossis, Alstonia scholaris andDiospyros embryopteris located in urban areas of Punjab, Pakistan. Different varities of tissues were found to have different concentration of trace elements when compared among themselves. Significant pollution has been observed.

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Abstract  

In order to determine the effect of airborne emission of trace elements, e.g. Br, Rb Cs, Sc and Na on roadside ecosystem, concentrations were determined in different species of plants from an urban park at Lahore. For monitoring purpose attention was paid to the leaves ofSapindus mukorossis, Alstonia scholaris andDiospyros embryopteris. Different varieties of tissues were found to have different concentration of trace elements when compared among themselves. The concentration of trace element deposition was compared with the values reported in literature. Significant pollution was observed.

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Abstract  

The extraction of technetium (VII) by 4-(5-nonyl)pyridine has been investigated from different aqueous solutions. Separation from uranium and some fission products has been achieved in nitrate media. From the results of partition experiments, attempts have been made to deduce the nature of the extracted species.

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Abstract  

Enrichment of51Cr has been made by recoil enrichment using potassium chromate as the target material. Irradiation of four days at a neutron flux of 2·1013n·cm−2·sec−1 in the core of PARR, followed by a chemical separation using a new liquid-anion exchanger, diphenyl-2pyridylmethane (0.1M in chloroform) gives a product of high specific activity (>30 Ci per gram), suitable for medical diagnostic applications.

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Abstract  

The extraction of chromium(VI) from aqueous hydrochloric, nitric and sulfuric acid solutions by diphenyl-2-pyridylmethane(DPPM) dissolved in chloroform has been studied. Chromium(VI) is quantitatively extracted from hydrochloric acid solutions in the range 0.1–1M. With increasing acid concentration, the extraction of chromium diminishes and in concentrated acid solutions practically all the chromium remains in the aqueous phase. The quantitative back-extraction of chromium from the organic phase is possible with HCl or HNO3 at concentrations higher than 5M through the use of reducing agents. The composition of the extracted chromium(VI) species was studied in solution. The complexes (DPPMH)+HCrO 4 and (DPPMH)2Cr2O 7 are extracted for tracer and macro amounts of chromium(VI) respectively. The data have been utilized for the separation of chromium(VI) from base metal ions.

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The effects of aluminium on seed germination, shoot, root and dry weight of two wheat cultivars were studied. The seed germination of Triticum aestivum cv. 'Faisalabad 85' and Triticum aestivum cv. 'Blue Silver' was significantly (p < 0.05) affected by different concentration of aluminium as compared to the control. The increase in concentration of aluminium at 10 ppm suppressed the root and shoot length in T. aestivum cv. 'Faisalabad 85', whereas the reduction in shoot length was observed for T. aestivum cv. 'Blue Silver' at 15 ppm. A significant (p < 0.05) reduction in dry weight of 'Blue Silver' was observed at 25 ppm aluminium.

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Abstract  

A study of the distribution of gallium(III) between hydrochloric acid solutions and 0.1M 4-(5-nonyl)-pyridine in benzene has been undertaken. Gallium can be quantitatively extracted from moderate to concentrated acid solutions and also from dilute acid solutions containing high concentrations of neutral cations of high charge density. The effects of acidity, the solvent concentration and diverse ions on the extraction have been investigated. An attempt has been made to elucidate the stoichiometry of the extracted species. The formulation of (NPy H)+ GaCl 4 ) and (NPy−H−NPy)+ GaCl 4 is expected at macro and trace concentrations of the metal. The extraction coefficients of several elements have been recorded under conditions optional for the extraction of gallium; and their factors for separations are estimated.

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