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El Ati Hellal M.,University of Tunis | Hellal F.,CNRS Institute of Chemistry | El Khemissi Z.,Institute Of Biotechnologie Of Sidi Thabet | Jebali R.,Institute National Of Recherche Et Danalyses Physico Chimique | Dachraoui M.,University of Tunis
Bulletin of Environmental Contamination and Toxicology | Year: 2011

The mean concentrations of copper, zinc, plomb, nickel and chrome were determined in algae and sediments collected from three aquatic areas of the Tunisian North-East (Sebkhet Sijoumi and Radès and Bizerte lagoon). The recorded metal levels, ranging (in μg g -1) from 1.58 to 68.56 for macroalgae and from 8.70 to 234.40 for sediment samples, were low in most of the sampling locations and similar to those of sites qualified as «slightly polluted». However, certain locations showed significant differences with the remaining sites indicating some degree of contamination (ANOVA, p < 0.001). These locations were found in Sebkhet Radès and Bizerte lagoon for copper, zinc, nickel and chrome metals and in Sebkhet Sijoumi for plomb in algae. The study of the correlation between metal contents in algae and sediments showed highly significant positive values for zinc and plomb (p < 0.01). A significant correlation was also noticed for Cr (p < 0.05). However, there was no clear relationship between copper and nickel levels in both matrices. © 2011 Springer Science+Business Media, LLC.

Chebab S.,Institute National Of Recherche Et Danalyses Physico Chimique | Chebab S.,French National Center for Scientific Research | Abdellaoui M.,Institute National Of Recherche Et Danalyses Physico Chimique | Latroche M.,French National Center for Scientific Research | Paul-Boncour V.,French National Center for Scientific Research
Materials for Renewable and Sustainable Energy | Year: 2015

The AB3-type LaCaMgNi9 compound was synthesized using mechanical alloying (MA) starting from elemental La, Ca, Mg, and Ni in the atomic ratio 1:1:1:9. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to study the phase evolution and formation/kinetic mechanism as a function of milling time (4-30 h). The results show multiphase alloys containing LaCaMgNi9 as a main phase with trigonal PuNi3-type structure (R-3m space group) where Ca atoms occupy preferentially the 3a site, while La and Mg atoms occupy the 6c site with a mean composition CaLa1.2(2)Mg0.8(2)Ni9. The hydrogenation properties of the alloys were examined by solid-gas reaction at room temperature. The PCI curves showed a plateau pressure of 0.25 bar which corresponds to the AB3 phase. The hydrogen absorption capacity of the AB3 phase is equal to 5.6 H/u.fAB3. © 2015 The Author(s).

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