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- Author or Editor: M. El-Dessouky x
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Abstract
Ampicillin-cobalt complex has been investigated spectrophotometrically. The effects of pH and molar ratio of ampicillin to cobalt were studied. The stability constants for the complex formed at different pH values were determined. Gamma-radiolysis of ampicillincobalt complex in aqueous solutions was studied at doses from 20 to 100 Gy, using a137Cs source. The variations in UV and IR spectra due to their radiolysis were shown. The results showed an increase in absorbance values with increasing dose and this dependence is linear in the dose range studied. The mechanism of radiation effect on the complex is discussed.
Abstract
Distribution of Hg2+, Co2+, Sc3+ and Eu3+ between the cation exchanger Dowex-50X8, [H+] (100–200 mesh), and 1M HNO3 solution containing different benzylamine (BA) concentrations has been studied. The distribution coefficient, D, for Co2+, Sc3+ and Eu3+ is very small and does not vary seriously with the BA concentration. It is also found that Hg2+ is highly taken by the resin from the media studied. In this respect, D increases with increasing BA concentration to reach a maximum at 0.5% BA in 1M HNO3. This behaviour is explained by the exchange of molecular species between the cation exchanger and the aqueous phase. Based on the results, a radiochemical separation procedure for the selective isolation of Hg2+ from Co2+, Sc3+ and Eu3+ has been developed. The radiochemical purity is not less than 99.8% and the chemical yield more than 95% for the separated203Hg.
Abstract
Separation of Cs, Sr and Ca from their mixture was studied using solvent extraction and ion exchange techniques. More than 90% separation efficiency was achieved for Ca–Sr separation using ion exchange resin (Doulite C-20) while solvent extraction amounted to 88%. A proposed technique for determination of137Cs and89Sr in milk (after removal of organic matter) showed more than 80% accuracy for89Sr determination and more than 90% for137Cs determination.
Abstract
Extraction of lanthanides and actinides were found to be synergically enhanced by a mixture of bis/2-ethyl hexyl/phosphoric acid /HA/ and dinonylnaphthalene sulfonic acid /HD/ in aromatic diluents covering a wide range of dielectric constant. The main extracted species is found to be in the form MA2Hm–1Dm. Experimental results indicate that the extraction mechanism is governed by the extraction of HD in the organic phase.
Abstract
Chelation studies of cobalt(III) with 1,2 bis(beta-aminoethoxy)ethane N,N,N',N' sodium sulfonate triacetic acid (ASTA) were performed. The results showed the effectiveness of ASTA as a chelating agent by using: molar ratio, continuous variation and slope ratio methods. Stable complex 1∶1 was formed at pH from 6.0 to 10.5. Solutions of Co-ASTA chelate of different molar ratios at pH 6.5 and 8.0 were irradiated by different gamma-radiation doses. The results showed a linear decrease of absorbance with gamma-radiation dose which can be utilized as a dosimeter for low dose rate measurement in the range studied. A proposed radiolytic mechanism is discussed. The degradation of the ASTA ligand has been related to hydroxyl radical attack.
Abstract
2-hexanoyl-5-(2-hydroxy 2-propyl)furan (HHPF), has been investigated as the principal product of radiolysis of 2-hexanoyl-furan (HF) in 2-propanol. The effect of absorbed dose on the product yields has been examined. Possible mechanisms for the formation of radiolytic products are discussed.
Abstract
The principal products of radiolysis of 1-(2-furanyl)-1-pentanone (FP) in 2-propanol in the presence of atmospheric oxygen were determined using a gas chromatograph coupled with a mass spectrometer. The principal products detected were:1-[2-(5-hydroxy-4-hydro) furanyl]-1-pentanone (HHFP), and 1-[2-(5-hydroxy-4-methyl) furanyl]-1-pentanone (HMFP).The radiation yield G has been determined and mechanisms for the formation of the radiolytic products are proposed.
Abstract
Sorption of cesium and strontium ions on hydrous titanium dioxide from chloride medium was studied. The prepared oxide showed relatively good ion exchange capacity for both metal cations in neutral medium, which is advantageous in liquid waste treatment. Distribution coefficient measurements under variable conditions indicated almost an ideal ion exchange behavior towards Cs+ and Sr2+ in the acidic pH range, with higher affinity towards Cs+ than Sr2+. Their sorption follows the Freundlich adsorption isotherm. Application of the oxide to column operation against solutions of 10-4M metal (Cs+ or Sr2+) chloride in 10-2M NaCl is attempted.
Abstract
Two antimonic acid samples were prepared and designated as hydrolyzed (H-SbA) and refluxed (R-SbA) antimonic acids. Their structure and ion exchange behavior towards Na+ as a simple ion is investigated. R-SbA samples showed higher degree of crystallinity and slightly higher ion exchange capacity than the other sample although it had slightly lower water content. Thermal treatment of both samples showed an increase in their ion exchange capacity on heating up to 200 °C. On further heating up to 400 °C the capacity is appreciably decreased. Equilibria measurements of both samples in dilute solutions showed almost an ideal ion exchange behavior. The obtained data are discussed in detail.
Abstract
Gamma-radiolysis of folic acid and its cobalt complex were studied in aqueous solutions at doses ranged from 2 to 10 krad and from 2 to 10 Mrad using60Co source. The variations in their spectra of IR, UV, and visible due to their radiolysis were shown. Also the change in pH after radiolysis was determined. The results showed that decomposition of folic acid by gamma-radiation occurred without variation of pH. Fine measurements of pH for irradiated CoCl2 and cobalt-folic acid complex solutions can be utilized for dose determination in the studied range of 2–10 Mrad. IR spectra showed that addition of cobalt chloride to folic acid decreased its decomposition by gamma-radiation. This result proved the importance of addition of cobalt chloride in keeping foodstuffs, which contain folic acid, by irradiation. The mechanism for the effect of radiation on cobalt chloride and cobalt-folic acid complex was discussed.
