Browsing by Author "Souag, Rafika"

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Adsorption des métaux lourds (Pb et Cd) sur une poudre de kératine en milieux aqueux
(2019) Nedjari, Roukia; Souag, Rafika
L’adsorption est une méthode d’élimination des différents polluants présent dans les eaux en revanche les adsorbants utiliser tel que le charbon actif et les autre adsorbants cout chère donc il exige de utiliser des adsorbants économiques. L’intérêt de ce travail est l’étude d’adsorption des ions plombe et le cadmium par un adsorbant économique préparer à base de poudre de kératine. Dans ce travaille on a préparé une poudre de kératine par des cornes des mouton pour l’adsorption des ion Pb et Cd sous l’influence des différents paramètres tél que le temps de contact ,la granulométries le pH, la concentration, , la masse d’adsorbant ou on a déterminer les paramètres physicochimique optimale pour l’adsorption des ion M2+ examiner ainsi on a identifié isotherme d’adsorption adéquate pour chaque ion dans le quelle le modèle de Freundlich est le modèle convenable pour l’adsorption des ion Pb2+et Cd2+ .
Adsorption of heavy metals (Cd, Zn and Pb) from water using keratin powder prepared from Algerien sheep hoofs
(European Journals Inc, 2009) Souag, Rafika; Touaibia, D.; Benayada, B.; Boucenna, A.
Effect of crystallization time on the structure of the Aluminosilicate glass-ceramic
(IOP Publishing Ltd, 2018) Souag, Rafika; Nidal, Kamel; Moudir, Dalila; Mouheb, Yasmina; Kamariz, S.
All This study deals with the influence of the time of crystallization on the structure of an aluminosilicate glass-ceramic ceramized by a nucleation –crystallization treatment at 790°C for 2 h, and 900°C, for different periods of time ranging from 2 to 12 h. For the whole of the materials, Archimedes density is between 2441-2578 kg/m3. Both X-ray diffraction and scanning electron microscopy analyses reveal two main crystalline phases for the whole of the heating treatments, namely spodumen and leucite. These phases grow regularly with the crystallization time. In addition, aqueous stability testing was carried out using the standard MCC-2 static leach test method at 90 °C and V(ml) = 30 S(cm2) for a series of five test durations - 7, 14, 28, 35 and 42 days. The X-ray fluorescence analytical technique was used to determine the concentration of lanthanum (La) and molybdenum (Mo) leached in our material. The dissolution parameters, in this case the normalized elemental mass loss (NL) and the leaching rate (τ) of each element, were determined from these concentrations. The results demonstrate that The leaching tests showed that the material is stable and it stabilizes at low values (2.5 10−9Kg/m2) for La when the ceramization time does not exceed 4h beyond this, Leaching equilibrium and the passivation phase is broken. For Mo and for all glass ceramics at different times of crystallization, the equilibrium reaches (3.15 10-8 Kg/m2j) and the passivation layer is formed. The glass ceramics at different time of cristallization presently studied appears to have a good chemical durability.
Effect of the ce content on a nuclear waste glassy matrix in the system SiO2-Al2O3-CaO-MgO-ZrO2-TiO2, synthesized at a low melting temperature
(DAVID PUBLISHING, 2013) Nour-el-Hayet, Kamel; Moudir, D.; Ziane, K.; Djerridi, A.; Mouhamou, S.; Benmounah, A.; Souag, Rafika; Taouinet, M.; Ait-Amar, H.
Aluminosilicated glasses containing Zr and Ti metals have satisfactory properties, and may be suitable as nuclear glasses, dedicated for storage of radioactive waste solutions. This study summarizes the synthesis of a glassy matrix in the system: SiO2-Al2O3-CaO-MgO-ZrO2-TiO2. Ce element was added as an actinide surrogate. The effect of Ce addition on the glass structure is investigated, for Ce contents ranging between 0 and 15 wt.%. For the whole of glasses, a double melting at 1,350°C during 5 h gave monophasic homogeneous glasses. Both X-ray diffraction and scanning electron microscopy analyses reveal a pure amorphous structure. Most of the basic properties increase with the glass Ce content, the Archimedes density from 2.827 to 3.049 g/cm3, and Vickers indentations from 680 to 862 HV. Oxygen molar volumes are not affected by the glasses Ce contents. The differential thermal analysis show that the glass transformation temperature decreases with the Ce content, and with the heavy elements content. The optical absorption spectroscopy study shows that the Nd cations environment is not altered by the glasses Ce concentration. A preliminary corrosion test leads to low dissolutions of Si, Ca and Zr, estimated by ICP analyses to few ppms. Out coming investigations are in course for further glasses network characterizations
Elaboration et mise en oeuvre des matériaux inorganiques /Spécialité : Chimie inorganique Semestre 3 -MASTER 2
(Faculté Des Sciences :Département De Chimie, 2022) Souag, Rafika
Les céramiques et les verres constituent une famille de matériaux d’une extrême importance, cette importance ne cesse de se développer au vu des caractéristiques qu’ils assurent et surtout pour des applications spécifiques nécessitant une tenue sous de très hautes températures et des chargements intenses. Cette importance se manifeste aussi dans leurs utilisations au quotidien et avec des quantités gigantesques à l’échelle du globe comme matériaux de construction ou comme matériaux d’utilisation domestique.....
Optimisation des conditions de synthèse d'une vitrocéramique à base d'aluminosilicates, utilisée pour le confinement des DRVL : etude de la durabilité chimique dans un milieu argileux
(2015) Souag, Rafika
L'objectif de ce travail est l'étude expérimentale des mécanismes d'altération de matériaux synthétiques vitrocristallins : verres aluminosilicatés appartenant au système (SiO2-Al2O3-MgO) et céramiques à base de Ti et/ou Zr. Cette thématique rentre dans le cadre d'un axe de recherche sur la gestion des radionucléides à vie longue, et s'intéresse aux processus chimiques qui contrôlent la dissolution des solides cristallisés ou amorphes. Des différents matériaux ont été synthétisés par des méthodes de synthèse par voie sèche. L'optimisation des conditions de synthèse a été réalisée. Une étude détaillée des processus d'altération des matériaux dans un milieu aqueux, à différentes conditions (à 25 °C dans un système ouvert et à 100 °C dans un système fermé) et en milieu argileux. Des résultats concluants ont été obtenus avec l''ensemble des matériaux synthétisés. Ces derniers ont montrés une bonne stabilité chimique, et par conséquent, ils peuvent être utilisés pour le confinement des déchets radioactifs
Study of leaching of a 2M-Zirconolite (Ca0,83Ce0,17ZrTi1,66Al0.34O7) in acidic and basic media
(2015) Souag, Rafika; Kamel, N.; Hammadi, M.; Kamel, Z.; Moudir, D.; Aouchich, F.; Kamariz, S.
Zirconolite is a mineral intended for actinides elements confinement and is known for its good chemical durability. In this work, 2M-zirconolite, with the chemical formula: Ca0,83Ce0,17ZrTi1,66Al0.34O7 have been synthesized at 1400 o C by the metallurgical route at a laboratory scale. This stoechiometry corresponds to a CeO2 loading of 8.61 m.%. Ce is employed as an actinide surrogate. The effect of both pH and temperature on the chemical durability of this mineral has been studied. Phase identification and micrography observations have been done by X-ray diffraction, scanning electronic microscopy, and Fourrier transform infra-red spectroscopy. The end-product has a monophasic structure of 2M-zirconolite. Its density is about 4.013 g/cm3 , and its relative density is of 96 %TD. It has a microhardeness of 370 MPa. The Ce behavior in leaching media of extreme pH values: acidic medium (pH = 2) and basic medium (pH = 12), at 23 o C and 70 o C, shows that the Ce dissolution speeds are faster at 70 o C compared with those obtained at 23 o C. The 2M-zirconolite matrice presently studied appears to have a good chemical durability
Study of the effect of Ca/Mg alkali-oxides ratio on the structure of a glass-ceramic based on an aluminosilicated glass containing 2wt.% of zirconolite crystalline phase
(2014) Souag, Rafika; Kamel, N.; Mouheb, Y.; Hammadi, M.; Kamel, Z.; Moudir, D.; Aouchich, F.; Kamariz, S.
New nuclear glass-ceramics are extensively studied for the radioactive waste confinement, due to the double confinement conferred by the glass-ceramics. In this study, a glass-ceramic constituted by an aluminosilicate glass in the system: SiO2-Al2O3-CaO-MgOZrO2-TiO2, containing 2wt.% of Ca0.83Ce0.17ZrTi1.66Al0.34O7 zirconolite, has been synthesized by the discontinuous method. Cerium, an actinide surrogate is introduced both in the glass and ceramic phases. The synthesis is performed by a double melting at 1350 °C, followed by a nucleation at 564°C, during 2 h, and a crystal growth at 1010°C during 3 h. Then effect of Ca / Mg ratio on the distribution of the crystalline network in the material was studied for Ca / Mg ratios ranging from 0.4 to 5.5. For the whole of the materials, Archimedes density is about 2.80 g/cm3 . X-ray diffraction (XRD) analysis shows that the increase of Ca/Mg ratio leads to the increase of aluminosilicated crystalline phases with high Ca contents; the materials molar volumes remaining constant. The zirconolite phase is not affected by these additive aluminosilicated phases. The scanning electron microscopy analysis (SEM) coupled with energy dispersive X-ray (EDX) analysis confirmed these results; and shows the uniformity of distribution of the ceramics in the bulk of the materials
TiO2 addition into nuclear glass ceramic : study of the crystalline phases, structure and chemical durability
(Hanyang University, 2022) Souag, Rafika; Kamel, Nour Elhayet; Moudir, Dalila; Mouheb, Yasmina; Aouchiche, Fayrouz
This paper studies the nuclear glass ceramic based on aluminosilicate glass. It is proposed the addition of TiO2 on the crystalline phase. The structure and chemical durability have been investigated. The materials with four TiO2 contents, ranging from 4.11 to 7.11 wt.%, are synthesized by a discontinuous method. The 7.11 wt.% TiO2 glass ceramic synthesis was not successful and crystallizes during the melting stage. For the others materials, Archimedes density ranges between 2.891 and 2.962 g/cm3. For the majority of materials, X-ray diffraction analysis allows the identification of an aluminosilicate that belongs to pyroxenes silicates family as the initial phase, powelite and calzirtite. These phases are known as radionuclides’ sequestration minerals. Both SEM and DTA analyses confirm these findings. The FTIR analysis of materials reveals the complex glass-ceramics chemical composition. MCC1 and MCC2 tests, performed on selected glass ceramic materials, indicate that the materials containing 4.11 and 5.11 wt.% TiO2 are the most durable against Si, Al, Mg and Ce elements release, in MCC2 test; the Ce (minor actinide surrogate) leaching rate being negligible (193.7☓10-9 kg/m2d after 28 leaching days for 5.11 wt.% of TiO2 content). These results make valuable conclusions for the selection of the glass ceramic suitable to the high-level waste disposal