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Howari F.,Zayed University | Goodell P.,University of Texas at El Paso | Salman A.,Nuclear Material Authority
Journal of African Earth Sciences | Year: 2016

This paper is briefly involved in classification and distributions of the Middle East and North Africa (MENA) uranium deposits. The study of these mineral systems can significantly contribute to our further understanding of the metallogeny of known and poorly explored deposits. This provides contribution to, and further enhancement of, current classifications and metallogenic models of uranium systems, allowing researchers to emphasize on unknown or poorly studied mineral systems found in MENA. The present study identified eight metallogenic types of uranium associated with: 1) the Archean rocks and intra-cratonic basins, 2) the Pan-African granites and rhyolites which are characterized by igneous activity, 3) Phanerozoic (Paleozoic) clastics, these deposits are the sedimentological response to Pan African magmatism, 4) Mesozoic (basal) clastics type e.g. Nubia sandstones which are characterized by uranium minerals, 5) regional sedimentary phosphate deposits which are categorized as geosynclinal, or continental margin deposits, on the shelf of the Tethys Ocean, 6) Cenozoic Intracratonic Felsic Magmatism of the Tibesti and Hoggar, and the sandstone U deposits of adjoining Niger. These are similar to the Pan-African magmatism metallogenic, 7) Calcretes, and 8) Resistate minerals which are often enriched in rare earth elements, sometimes including uranium. They are thus sometimes considered as U resources but poorly explored in the MENA region. These metallogenic types are described and discussed in the current paper. © 2015 Elsevier Ltd. Source


Mahmoud M.A.,Nuclear Material Authority | Mahmoud M.A.,Jazan University
Journal of Saudi Chemical Society | Year: 2016

The adsorption kinetics for removal of uranium (V1) from aqueous solution using silicon dioxide nanopowder (nano-SiO2) was investigated in batch and continuous techniques. Pseudo-first order and pseudo-second order were used to analyze the kinetics of batch experiments. In continuous technique the important parameters (initial concentration, flow rate and bed height) on the breakthrough curves were studied and the adsorption kinetics was analyzed using Thomas and Yoon and Nelson kinetic models. The comparison between the kinetic models was evaluated by the correlation coefficients (r 2). The results indicated that the batch experiments fitted well with pseudo second-order kinetic model. The comparison of the experimental breakthrough curve to the breakthrough profile obtained from Thomas and Yoon and Nelson methods showed a satisfactory fit for silicon dioxide nanopowder. © 2016 King Saud University. Source


Mahmoud M.A.,Nuclear Material Authority | Mahmoud M.A.,Jazan University
Journal of Environmental Chemical Engineering | Year: 2015

Abstract Sorption of uranium(VI) from aqueous solution onto powdered corn cob has been carried out using batch technique. The maximum removal (98.5%) was obtained at pH 5 and contact time 60 min. Freundlich, Langmuir, Temkin and Dubinin-Radushkevich (D-R) isotherms are used for describing the sorption process. It is found that the Langmuir isotherm appears to be the best fitting model and pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion kinetics models were studied. The results indicate that the process follows the pseudo-second-order kinetics model. As well as the thermodynamic data indicate that the sorption processes is exothermic. The values of enthalpy (ΔH°), mean free energy (E) and activation energy (Ea) indicate that the sorption process is physical sorption. A single stage of batch adsorber has been designed for various volumes using the Langmuir isotherm. © 2015 Elsevier Ltd. Source


Mahmoud M.A.,Nuclear Material Authority | Mahmoud M.A.,Jazan University
Process Safety and Environmental Protection | Year: 2016

Aluminum oxide nanopowder (AONP) was used for the preconcentration and recovery of uranium ions from an aqueous solution. Adsorption process in batch system was carried out by varying pH, initial U(VI) concentration, adsorbent dose, adsorption time and temperature. The adsorption efficiency could reach 99.85% at pH 5.0, 150 mg dose and 303 K. Desorption of uranium ions can be carried out using 1.5 M HNO3. Equilibrium adsorption was attained within 40 min at 303 K and within 20 min at 333 K indicating that the rate of U(VI) uptake was found to be faster with increasing temperature. Adsorption data indicates the process following Langmuir isotherm and pseudo-second-order kinetic model. The mean energy, enthalpy, and activation energy confirming that the adsorption of U(VI) onto AONP is physical adsorption. Moreover, the thermodynamic parameters showed the endothermic and spontaneous nature of the adsorption process. © 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Source


Mohammed H.,Nuclear Material Authority | Sadeek S.,Zagazig University | Mahmoud A.R.,Nuclear Material Authority
Microchemical Journal | Year: 2016

Uranium and thorium have been measured in oil ash samples collected from four Egyptian power plants that use heavy fuel oil. The U and Th content in oil ashes was determined by INAA, ICP-MS, ICP-OES, WDXRF, and EDXRF without any sample pretreatment. Samples were digested using two acid, four acid, or fusion method. The concentration of U and Th were found to be within the average worldwide value. Uranium and thorium content in heavy fuel oil were also measured for the first time. For quality control of the analytical data, three internal reference materials were prepared and used. © 2015 Elsevier B.V. Source

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