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  • Author or Editor: R.S. Singh x
  • Chemistry and Chemical Engineering x
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Abstract  

The general method of evaluating the temperature integral for temperature dependent frequency factors have been considered. The values of the temperature integral as evaluated by the present method are in excellent agreement with those obtained numerically.

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Abstract  

The distribution ratios for the extraction of Zr(IV) by TBP and its binary mixtures with DMSO or Py in n-dodecane in the presence of HNO3, and HClO4 have been determined. Based on stoichiometric and slope analysis methods a possible mechanism for the extraction has been proposed.

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Abstract  

The radiotracer technique has been applied to find the transference number of anion/cation constituents of iodine-alcohols “inner chargetransfer complexes” and it is deduced that the anions are the main charge carriers.

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Abstract  

Sorption behaviour of monovalent Rb+, Tl+ and Ag+ is studied on chromium fericyanide gel. Log Kd vs log concentration plots show that Rb+ and Tl+ are sorbed through ion exchange mechanism in a higher concentration range of ammonium nitrate or nitric acid, whereas the adsorption of Ag+ is irreversible. It was found possible to elute Rb+ and Tl+ on the columns of this gel by 4 mol dm−3 NH4NO3 and 10 mol dm−3 HNO3, respectively. Binary separations of Rb+ and Tl+ from a number of other metal ions were achieved as other ions were found practically unadsorbed on these columns and were eluted with water of pH 2–3. Achieved separations are of radioanalytical and analytical importance.

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Abstract  

A simple technique based on the measurement of the ratio of alpha-decay constant to neutron induced fission cross section for pure actinides using solid state nuclear track detectors (SSNTDs) is developed for the identification of the actinides in trace levels in pure solutions. The alpha-decay constant to fission cross section ratios for depleted U,238Pu and240Pu have been measured for the epicadmium neutron induced fission of these actinides. The measured values are (6.19±0.34)·106, (6.95±0.26)·1012, (2.12±0.95)·109 and (2.18±1.58)·1011 sec−1·cm−2, respectively. These ratios can be used for the trace level identification of pure actinides.

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Abstract  

Tracer diffusion of131I ions is studied at different temperatures /20°C–50°C/ in 2.5% agar gel containing sodium and potassium sulphate solutions over a wide range of concentrations. The results are in qualitative agreement with the theoretical values in the concentration range 10–6–10–1M. Agar gel shows an obstruction effect to diffusional flow. The activation energy for tracer diffusion was found to be of the order of 16.3 kJ mol–1.

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Abstract  

The order of extraction of Mo(VI) from 1M acid solutions by 5% (v/v) LIX 622 (HL) in benzene is HCl>HNO3>HClO4>H2SO4, and extraction decreases with increasing concentration of HCl and H2SO4, and increases slightly with increasing concentration of HNO3 and HClO4. The extracted species is shown to be MoO2L2 as established by IR data of organic extracts and the extracted species in the solid form. Extraction is almost quantitative at and above 10% LIX 622, and is found to be independent of [Mo(VI)] in the range of 10–4 to 10–3 M. The diluents CCl4, CHCl3 and C6H6 are found to be superior to solvents of high dielectric constant for extraction of Mo(VI). Extraction of uranium(VI) by 10% (v/v) LIX 622 in benzene was found to increase with increasing equilibrium pH (3.0 to 6.0), and becomes quantitative at pH 5.9. Tributyl phosphate acts as a modifier up to 2% (v/v). Thorium(IV) is almost not extracted by LIX 622 or its mixture. Separation of Mo(VI) and U(VI) is feasible.

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Abstract  

The extraction order of Th(IV), U(VI) and Mo(VI) based on pH0.5 values is Mo(VI)>U(VI)>Th(IV). Quantitative extraction has been observed for U(VI) by mixture of 10% (v/v) LIX 84 and 0.1M dibenzoylmethane at pH 4.2 and by mixture of 10% LIX 84 and 0.05M HTTA in the pH range 5.5–7.3 and for Mo(VI) by 10% LIX 84 from chloride media at pH 1.5. The order of extraction of Mo(VI) from 1N acid solutions is HCl>H2SO4>HNO3>HClO4 and extraction decreases very rapidly with increase in the concentration of HCl as compared to that from H2SO4, HNO3 and HClO4 acid solutions. The diluents C6H6, CCl4 and CHCl2 are found to be superior ton-butyl alcohol and isoamyl alcohol for extraction of Mo(VI). Influence of concentration of different anions on the extraction of U(VI) and Mo(VI) has been studied. Very little extraction has been observed in case of Th(IV) by LIX 84 or its mixtures with other chelating extractants or neutral donors.

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Abstract  

Palladium was separated from Al, Ru, Rh, U, Pu and also from a mixture of fission products using -benzoin-oxime as the extractant and Solvesso-100 as the diluent. The extraction is quantitative over a wide range of acidity from 0.1M to 4M HNO3. The method has been found to be equally effective to separate Pd at trace level (carrier-free form). The stoichiometry of the complex, the interference of foreign elements in Pd separation, etc., are reported. The applicability of the method to separate palladium formed in fission rapidly from all other fission products, especially the most strongly interfering molybdenum isotopes, and the recovery of this element from high level radioactive waste are also mentioned.

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Abstract  

A simple method is reported in this paper to estimate229Th in the presence of228Th. The total activity of229Th and228Th was determined by following the alpha activity growth (using a liquid scintillation counter and proportional counter) of purified thorium samples. The activity ratio of229Th/228Th was determined by alpha spectrometry. From the initial total activity and ratio, disintegration rates of229Th and228Th were calculated. The values obtained for the activities have a precision better than ±2%.

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