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- Author or Editor: H. Aly x
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Abstract
The kinetics of the exchange of sulphate and chloride ions on the strongly basic anion exchanger Dowex 1X8, of different particle diameters is investigated. The diffusion coefficient values are calculated by two diferent methods, discussed in the light of the processes governing the exchange reactions encountered, and found to be mainly controlled by particle diffusion. The distribution behaviour of sulphate, sulphite, thiosulphate and sulphide between aqueous KCl solutions of different concentrations and a number of selected anion exchange resins is studied. The data are explained on the premises of the different interactions involved in both aqueous and resineous phases. The effect of the alkali metal chloride molarities in the aqueous phase (LiCl, NaCl and KCl) on the exchange behaviour of the different S-anions is also investigated. The results are interpreted in the light of the water—water interaction and the competition for hydration between the alkali metal cations and the exchanged S-anions.
Abstract
The distribution of UO 2 2+ , Ce3+ and Am3+ between Chelex-100 and 0.2 and 5.0M ammonium thiocyanate solutions of different hydrogen ion concentrations has been investigated. The results obtained are compared with parallel experimental results using the anion exchanger Dowex-1×4 and the cation excharger Dowex-50×8. It is found that Chelex-100 can act as anion exchanger at pH<2 and as cation and chelate exchanger at higher pH. A main feature of the distribution results of UO 2 2+ , Am3+ and Ce3+ with Chelex-100 is the very high distribution coefficient for the three cations at pH higher than 3.5 from aqueous solutions containing 0.2 or 5.0M ammonium thiocyanate.
Abstract
The distribution of UO
2
2+
and Th4+ in nitric acid media on crypomelane-type hydrous manganese dioxide (CRYMO) has been investigated by batch equilibrations and column break-through techniques. The parameters studied involve the media composition and concentrations of HNO3, NaNO3, UO
2
2+
and Th4+. It is found that Th4+ is more strongly adsorbed on CRYMO than UO
2
2+
with sufficient differences for chromatographic separation from each other. Uranium was quantitatively eluted from a CRYMO column with 0.1M HNO3. Th4+ has been recovered by using 
1M HNO3 as eluent.
Abstract
12-molybdocerate(IV) gel labelled with99Mo has been prepared via isotope exchange between a column of inactive molybdate matrix and a mobile solution of99-Mo-sodium molybdate(VI) in 0.1 mol·dm–3 HNO3. The composition and nature of the reaction mixture, concentration of Mo(VI) in the reactants, reaction temperature and/or drying temperature of the gel matrix on the exchange yeild of99Mo and time of reaction are explored using the batch equilibration and/or the chromatographic column methods. The obtained material is evaluated for use in preparation of elution-type99Mo-99mTc generators.
Abstract
Selective efficient method have been for separation of palladium by strong basic anion exchangers IRA-410 and IRA-900 from intermediate radioactive nitrate medium. The different conditions for exchange behaviour of palladium from [ILLW] solutions containing numbre of elements were investigated by batch technique. Selective recovery of palladium from the [ILLW] solution was achieved using column technique. The elution of palladium was carried out via reduction with formic acid where the rate of the reduction process was increased by decreasing the formic acid concentration till 50% followed by dissolving the separated palladium by nitric acid.
Abstract
In this work Strontium was separated selectively form, Pd2+, Ni2+ and Ca3+ using anionic resins of Amberlite type IRA-900 and IRA-410 from nitrate medium. The Separation of strontium by strongly basic anion exchangers IRA-410 and IRA-900 from simulated waste containing, Sr2+, Eu3+, Ce3+, Pd2+, Rh3+, Ru3+, VO2
2+, Fe3+, Cr3+, Ni2+, Al3+, Ca2+, and Cs+, in K2SO4/nitrate medium which adsorbed as strontium sulphate complex was achieved through ligand- ligan exchange. The elution of strontium carried out via 
loading
the column with a solution of 0.03N EDTA in presence of 0.1N NaNO3 at pH7 where Sr2+ has low Kd value. An inductively Coubled Plasma — Optical Emission Spectrometry (ICP — OES) of ARL type model 3520, was used for elemental analysis.
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.
Abstract
The solvent extraction of divalent iron, cobalt, copper and zinc from perchlorate medium of constant ionic strength (0.1 H+, NaClO4) into a mixture of thenoyltrifluoroacetone (HTTA) and dibenzylamine (DBA) in chloroform has been studied. The extraction of the different cations were found to increase by more than 103 order of magnitude in presence of DBA. Slope analysis of the extraction results assumed a general formula of M(TTA)2·DBA for the extractable adduct. A stability order of Fe(TTA)2·DBA>Co(TTA)2 ·DBA>Zn(TTA)2·DBA>Cu(TTA)2·DBA has been decumented.
Abstract
A method for the preparation of potassium nickel hexacyanoferrate complex K2NiFe(CN)6·3H2O (KNiFC) with acceptable properties was developed. The complex was characterized by its solubility in different nitric acid media, thermal stability, IR spectrometry, X-ray diffraction, and scanning electron microscopy. Utilization of the prepared potassium nickel hexacyanoferrate as ion exchanger for the removal of cesium and cobalt from radiocontaminants on laboratory scale using fixed bed technique was studied.
Abstract
Cerium(IV) antimonate was prepared by dropwise addition of 0.6M antimony pentachloride and 0.6M cerium ammonium nitrate solutions by a molar ratio of Ce/Sb 0.75. Exchange isotherms for H+/Co2+, H+/Cs+, H+/Zn2+, H+/Sr2+ and H+/Eu3+ were determined at 25, 40 and 60°C. Besides, it was proved that europium is physically adsorped, while zinc, strontium, cobalt and cesium are chemically adsorbed. Moreover, the heat of adsorption of zinc, strontium, cobalt and cesium on cerium (IV) antimonate was calculated and indicated that cerium(IV) antimonate is of endothermic behavior towards these ions. Also the distribution coefficients of these ions were determined and it was found that the selectivity is in the order: Eu3+>Sr2+>Cs+>Na+.
