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Abstract  

The concept of using paper chromatography on papers impregnated with liquid anion or cation exchangers is extended to the separation of trace elements through filtration on filter papers loaded with suitable extractant. The uptake of uranium, thorium and lanthanum from HCl and HNO3 media of different molarities by a filter paper treated with tri-octyl amine (TOA) is investigated. The effect of the different parameters on the uptake of the studied elements is experimented. A simple and fast radiochemical procedure is developed for the separation of La, Th and U from each other.

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Abstract  

Tributyl phosphate was used in reprocessing of spent nuclear fuel inthe Purex process. The amount of uranium retained in the organic phase dependson the type of TBP/diluent. Destruction of spent TBP is of high interest inwaste management. The use of the oxidative degradation of TBP diluted withkerosene, carbon tetrachloride, benzene and toluene using potassium permanganateas oxidant was carried out to produce stable inorganic dry particle residuewhich is then immobilized in different matrices. The different factors affectingthe destruction of spent waste were investigated. The uptake and decontaminationfactor for both 152, 154Eu and 181Hf and the analysisof the final product have been studied.

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Abstract  

Synthesis and characterization of N,N,N',N'-tetrabutylsuccinamide (TBSA)was carried out and used for the extraction of U(VI) and Th(IV) from nitricacid solutions. Toluene was found to be the most suitable diluent for TBSAcompared with the other diluents tested. Extraction distribution ratios (D)of U(VI) and Th(IV) have been studied as a function of aqueous HNO 3 concentrations,NO3 – ion concentration, TBSA concentration and temperature.The results obtained indicated that U(VI) and Th(IV) are mainly extractedas UO2 (NO3 ) 2 . 2TBSA and Th(NO3 ) 4 . TBSA, respectively, and the IR spectra of the extractedspecies have been investigated. The values of thermodynamic functions havebeen calculated. Back-extraction of U(VI) and Th(IV) from organic phases wasalso studied.

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Abstract  

3-Formyl-4-hydroxy-N-methyl 2(H) quinoline (FHMQ) was synthesized and characterized. This compound was found not soluble in water or nitric acid solutions of different concentration. The uptake of Zr and Th from nitric acid by FHMQ has been investigated. The effect of shaking time on the percent uptake was studied. It was found that the equilibrium uptake of Zr is reached in one step after 2 hrs while in case of Th 4 hrs was required to reach equilibrium. The effect of nitric acid, metal ion and FHMQ on Zr uptake was studied. Studies on the retention capacity of 3-formyl-4-hydroxy-N-methyl 2(H) quinoline showed that its capacity decreases by increasing the nitric acid concentration for both Zr and Th. From the results obtained a selective method for separation of Zr from Th and U(VI) was developed using a floating bed column.

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Abstract  

The extraction of radio-mercury(II) by PTTDT was investigated as function of diluent, hydrochloric acid concentration, extractant concentration and certain foreign compounds in the aqueous phase. The extraction was found to be quantitative when chloroform was used as diluent and at low HCl or high PTTDT concentrations. Neither the presence of boric acid, nor several metal salts (NaF, CuSO4, ZnSO4 or Na2SO4) had any effect on the E%. The presence of chloride or bromide lowers the E% considerably. A radiochemical procedure was developed to pre-concentrate mercury from artifical sea water using an organic: aqueous phase ratio of 1∶100.

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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  

The present overview presents a brief survey on the liquid-liquid extraction mechanism of metal chelates and adducts, the different reported reaction models and the most common methods used to follow the kinetics of extraction process are given. The effect of the different phenomena affecting the extraction rate and the importance of the kinetic information in connection with technical processes and counter-current modelling are also discussed.

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Abstract  

The kinetics of distribution of Am(III) and Eu(III) between thenoyltrifluoroacetone (HTTA) and triphenylarsine oxide (Ph3AsO) mixture in chloroform and aqueous nitrate medium has been investigated using a stirred Lewis cell at ionic strength of 0.1M. The effect of the concentration of HTTA, Ph3AsO, H+ and NO 3 on the rate of distribution of Am(III) and Eu(III) was studied. The results were interpreted by reaction mechanisms where the rate-determining steps are the parallel reactions of Am(OH)2+ or Eu(OH)2+ with one HTTA molecule and one Ph3AsO molecule in the aqueous medium. The values at 25 °C of the rate constantk HLL (HL=HTTA andL =Ph3AsO) are 1.6±0.3·106M–2·s–1 and 2.3±±0.3·108M–2·s–1 for Am(III) and Eu(III), respectively.

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Abstract  

The removal efficiency of moderate levels of radon from groundwater supplies was evaluated using the diffused bubble aeration technique. An aeration system was designed, constructed and operated for that purpose. The effect of air-to-water ratio and detention time on radon removal were evaluated through 32 runs. The possibility to reduce the radon activity in the influent stream to the U.S. Environmental Protection Agency proposed maximum contaminant level (MCL) was verified through many alternative combined values of both air-to-water ratios and detention times. The results showed that at detention time of 19 minutes and air-to-water ratio of 12, the average radon removal is about 97%. The stripping constant characterizing this system was calculated and the removal efficiency at extended values of detention time was predicted. The data obtained are site specific, being dependent on container size, type of diffusers, temperature, and influent radon radioactivity.

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Abstract  

Humin is separated from a soil sample and characterized by elemental analysis, IR and potentiometric titration. These investigations indicated that humin displayed similar characteristics as humic acid. The sorption behavior of137Cs,90Sr and153Gd with humin was investigated from aqueous solution. The results indicated that the sorption process follows the order: Gd3+≫Sr2+>Cs+. It was time dependent and increased with pH. The sorption in the presence of humic acid or EDTA showed that both form a metal-ligand complex and consequently decrease the % uptake.

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