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  • Author or Editor: H. Dessouky x
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Abstract  

The extraction behavior of octahedral and tetrahedral cobalt(II) complexes from aqueous nitrate medium was studied in the system 8-hydroxyquinoline (HOX) and dibenzo-18-crown-6 (Db 18C6) or dibenzylamine (DBA) in chloroform at different temperatures to evaluate the thermodynamic functions as well as the equilibrium constants of each reaction. The stoichiometry of the extracted organic phase species were established to be Co(OX)2·Db18C6 for the octahedral cobalt and Co(OX)2·DBA for the tetrahedral cobalt.

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Summary  

Macroporous methyl methacrylate polymeric resin (XAD-7) was investigated incorporating both acidic organophosphorous extractant (cyanex-301) and one neutral extractant from the followings: dibenzo 18 crown 6 (DB18C6), 18 crown 6 (18C6) and 15 crown 5 (15C5). The sorption behavior of the solvent impregnated resin (SIR) towards thorium ion, including batch equilibrium, and kinetic operation are described. Different factors affecting the uptake of metal ions and hence, the separation efficiency of the impregnated resins were investigated. The maximum uptakes of Th4+ were found to be 62.9, 66.7 and 92.6% for DB18C6, 18C6 and 15C5, respectively. Synergistic extraction of various CE towards thorium ion was tested with cyanex-301 to enhance the sorption capacity as well as the selective separation efficiency. A relatively high capacity of the chelating resin towards tetravalent thorium was found. The capacities of the co-impregnated resins were found to be 2.11, 2.42 and 3.85 mmol/g for DB18C6, 18C6 and 15C5, respectively. The impregnated resin containing cyanex-301 and 15C5 can be utilized for selective separation and pre-concentration of thorium ion from nitrate medium in the presence of several interfering metal ions.

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Abstract  

Chromatographic column investigations were performed for the recovery of uranium from aqueous medium of pH 1.0 and ionic strength of 0.6M/NaNO3/, which is comparable /in its chemical activity/ to certain high active waste solutions. Six different active beds were tested and compared in terms of their capacity for uranium, height equivalent to theoretical plate and their numbers. The main uranium species present in the medium were elucidated.

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Abstract  

Synergic extraction of trivalent iron and cobalt with thenoyltriflouroacetone (HTTA) and the synergic bases (B) benzylamine (BA), dibenzylamine (DBA) and tribenzylamine (TBA) was studied. The extracted adducts proved to have the general formula M(TTA)3·B for all the amines investigated. The formation constants of the mixed-ligand complexes decrease in the order DBA>TBA>BA. While equilibrium constant β3,1 for the Co(TTA)3·DBA complex is higher than the corresponding iron adduct, β3,1 for the iron adducts with BA and TBA are higher than those for cobalt.

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