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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 212 (1996), S. 269-280 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Extraction of Pr(III), Ho(III) and Er(III) has been studied in the pH range of 1–10 with N-benzoyl-N-phenylhydroxylamine (BPHA) in benzene. The separation was found to be quantitative in borate media from pH 7 to 10, at an ionic strength of 0.1M (H+, BO3 3−). The stoichiometric composition of the complexes under the optimal conditions of shaking time, pH and reagent concentration was formulated using slope analysis and found to be M(BPHA)3, where M=Pr(III), Ho(III) and Er(III). The effect of various masking agents shows that citrate, ascorbate, EDTA, oxalate, fluoride and phosphate form stable complexes with these rare earths as compared to BPHA. The decontamination factors for different cations with respect to these rare earths under the optimum conditions have been evaluated.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 164 (1992), S. 1-11 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Synergic extraction of hydrolyzable lanthanides Dy(III) and Sm(III) has been studied in the low pH range with 0.3M (HTTA-TBA) in chloroform from aqueous perchlorate media. The synergic coefficient was calculated at different pH's and was found maximum at pH 3 for both elements. The composition of the adduct was established as M(TTA)3.3TBA at pH 3. However, a mixture of the adduct of the type M(TTA)3.TBA was proposed at pH 5.9. The possible reaction mechanism at both pHs is discussed, the stability constant βm,n′ formation constants Km,o and Km,n have been calculated.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 211 (1996), S. 283-292 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The sorption of Fe(III) at low pH range from 1 to 4.5 on open cell polyether type HTTA-loaded polyurethane foam has been carried out using batch technique. The optimum shaking time for 2.5· 10−4M solution of Fe(III) was found to be 30 minutes. The concept of macropore and micropore nature of polyurethane foam sorbent offers unique advantages of adsorption. Freundlich and Langmuir adsorption isotherms are followed at low concentration range from 1·10−4 to 3·10−4M solution of Fe(III). The Freundlich constant (1/n=0.46±0.013 andK=9.16±1.39 mg·g−1) and Langmuir isotherm constants(M=21.78 mg·g−1 andb=88.41±9.731·g−1) were established. The sorption mean free energyE=12.22±0.09 kJ·mol−1 and loading capacityC m =145.21±6.1 mg·g−1 were evaluated using Dubinin-Radushkevich isotherm, which suggested that the adsorption mechanism was chemisorption.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 211 (1996), S. 293-303 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The batch kinetics of Fe(III) adsorption on HTTA-loaded polyurethane (PU) foam have been investigated. The rate of controlling the adsorption is found to be intraparticle diffusion. The reaction rate of adsorption and desorption was also evaluated and found to increase and decrease with temperature, respectively. This indicates an endothermic adsorption behavior of Fe(III) on HTTA loaded PU foam. The activation energy of adsorption (80±10 kJ·mol−1) and of desorption (−45±±2 kJ· mol−1) indicates the chemical adsorption rather than physical adsorption. The isosteric heat of adsorption (δH ads) was found to be −82.7±5.05 kJ·mol−1. This shows the formation of new chemical bonds among Fe(III)-HTTA-PU foam. The thermodynamic parameters of δG, δH and δS, and equilibrium constantK c have been calculated. These functions further support that the process of adsorption of Fe(III) on HTTA-loaded PU foam is endothermic and chemisorption, stabilized through thermodynamic functions.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 246 (2000), S. 581-587 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The sorption of 60Co, 65Zn, 75Se, 103Pd, 110Ag and 203Hg radionuclides by polyurethane foam (PUF) was investigated and optimized with respect to the selection of appropriate sorptive medium, metal, thiocyanate ions (except for 110Ag) and PUF concentration and equilibration time. The influence of common anions and cations on the sorption of each metal was examined. The sorption data subjected to different sorption isotherms have shown that the sorption of all the radionuclides followed Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. The sorption capacity intensity and energy were evaluated for each element studied. The variation of sorption with temperature was monitored for all radionuclides except zinc and selenium. The values of ΔH, ΔS and ΔG were estimated and found to be negative indicating exothermic and spontaneous nature of sorption. It was found that PUF is an effective and economical sorbent for traces of metal ions which can be used for the separation/preconcentration of these ions from their very dilute solutions and has useful applications in radioanalytical and environmental chemistry and in radioactive and industrial liquid waste management.
    Type of Medium: Electronic Resource
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