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Abstract  

Sodiumlignosulphonate was added to sulphate resisting cement as chemical additive to modify its physical and chemical properties for conditioning hazardous and radioactive wastes for long term disposal. The effect of some organic and inorganic chemicals on sulphate resisting cement was investigated. The physical properties such as density, porosity percent and absorption percent for all the studied samples as well as the compressive strength values and the leaching properties were also determined. The thermal stability and the radiation stability were also investigated.

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Thermodynamics of dinonylnaphthalene sulfonic acid (HD)

Extraction of trivalent americium, curium and californium

Journal of Radioanalytical and Nuclear Chemistry
Authors:
M. Raieh
and
H. Aly

Abstract  

The effect of temperature on the extraction of the trivalent actinides Am3+, Cm3+ and Cf3+ with the liquid cation exchanger dinonylnaphthalenesulphonic acid (HD) in toluene is studied. The different thermodynamic functions of this system are determined from the experimental results. It is found that the free energy variation for the extraction of these metal ions by HD is mainly determined by the entropic terms arising from the hydration-dehydration process of the exchanged ions.

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Abstract  

A rapid method for fluorimetric estimation of uranium in silicate rocks is described. The fluorescence of uranyl complex is induced by laser beam in the ultraviolet region provided by nitrogen laser tube. The emission spectrum is quite intense and relatively persistent. For direct estimation of uranium in geological silicate materials without prior extraction, the interference of certain cations and anions that might be present in silicate rocks on uranium determination was studied. The limit of detection is 0.5 ppb.

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Abstract  

Different nitrogen fertilizers produced in Egypt were analyzed mass-spectrometrically for their15N content. The results indicate that nitrate fertilizers are relatively enriched in15N compared with ammonium fertilizers. The isotopic fractionation of nitrogen encountered in the production processes of fertilizers are discussed.

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Summary  

Many studies have shown that water hyacinth (Eichhornia crassipes) roots can be used to accumulate high concentrations of organic as well as inorganic pollutants. They are currently used to remediate aquatic environments and aqueous solutions. In the present study, sorption of uranium from aqueous solutions by using dried roots of water hyacinth has been investigated. The sorption of uranium was examined as a function of initial concentration, pH, weight of roots and contact time. Five different concentrations 20, 40, 60, 80, and 100 μg . ml-1 were used. Sorption proves to be very rapid and depend on pH, weight of roots and concentration of uranium. Maximum sorption capacity of water hyacinth roots was 64,000 U6+ μg/g. The sorption of uranium by water hyacinth roots follows a Langmuir isotherm.

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Abstract  

Zirconyl tungstate ceramic-supported membranes were developed and characterized. The transport process of Cs(I), Sr(II) and La(III) from the anode compartment to the cathode was investigated. The cationic fluxes for Cs(I), Sr(II) and La(III) were found to be 9·10–10, 2.7·10–9 and 2.4·10–9 g·eq·cm–2·s–1, respectively. The transport numbers of these cations were found to be 0.12, 0.07 and 0.09, respectively. Separation of Cs(I), Sr(II) and La(III) was achieved using EDTA as a chelating agent in the anode compartment. Cs(I) was successfully separated with a decontamination factor of 97% from simulated intermediate level liquid waste (ILLW) containing Cs(I) and Sr(II).

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Abstract  

The thermodynamic functions for the extraction of Sc3+ by liquid cation exchangers HD and HDEHP are determined radiometrically by the temperature coefficient method. The role of diluent dielectric constant on the extraction of Sc3+ by HD is also studied. The thermodynamic parameters determined indicated that the free energy variation for the extraction of Sc3+ by HD is mainly determined by the entropic terms arising from the hydration—dehydration process of the exchanged ions. In the case of HDEHP as extractant, the free energy variations are determined mainly by the entalpic terms of the system.

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Abstract  

Heterogeneous isotope exchange between hydrated stannic oxide and stannous chloride in 0.1M HCl solution has been studied as a function of the stannic oxide, stannous chloride, and chloride ion concentrations, and temperature. The exchange process is a second-order reaction, which is independent of the chloride ion concentration, with a mean rate constant, k, of 2.31 dm3 mol–1·min–1. The activation energy of the isotope exchange process was found to equal 3.62 kcal·mol–1. Possible use of this system, SnCl2/SnO2·xH2O, as basis for a113Sn-113mIn generator is suggested.

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Abstract  

The solid-state thermal reactions of 2,6-diamino-4-chloropyrimidine, 3,3-dimethoxybenzidine and of thiosemicarbazide with each of 2-hydroxy-1-naphthaldehyde and 2,4-dihydroxybenzaldehyde in a mole ratio of 1∶1 produced (1+1) condensation products (‘half units’). These solid state reactions have been studied by means of differential thermal analysis (DTA). The products of the reactions were identified using elemental analysis and IR spectroscopy. Some kinetic parameters such as orders and activation energies of the reactions were evaluated form the DTA curves.

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