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Azrour M.,Laboratoire Of Physico Chimie Des Materiaux | Azdouz M.,Laboratoire Of Physico Chimie Des Materiaux | Azdouz M.,Laboratoire Of Recherche Of Chimie Physique Generale Des Materiaux | Manoun B.,Hassan 1er University | And 7 more authors.
Journal of Physics and Chemistry of Solids

Synthesis of apatites, Na1-xKxPb4(PO 4)3 0≤x≤1, with anion vacancy was carried out using solid state reactions. The solid solution of apatite-type structure crystallizes in the hexagonal system, space group P63/m (No 176). Rietveld refinements showed that 75% of Pb2 cations are located in the (6h) sites; the ninefold coordination sites (4f) are equally occupied by the other 25% lead cations and the K and Na monovalent ions. The structure can be described as built up from [PO4]3- tetrahedra and Pb 2 of sixfold coordination cavities (6h positions), which delimit void hexagonal tunnels running along [0 0 1]. These tunnels are connected by cations of mixed sites (4f) half occupied by Pb2 and half by Na/K mixed cations. The assignment of the observed frequencies in the Raman and infrared spectra is discussed on the basis of a unit cell group analysis and by comparison with other apatites. The Raman modes of all the compositions show some linear shifts of the frequencies as a function of the composition toward lower values due the substitutions of Na by K with a larger radius. © 2011 Elsevier Ltd. All rights reserved. Source

Azdouz M.,Laboratoire Of Physico Chimie Des Materiaux | Azdouz M.,Laboratoire des ressources naturelles et environnement | Manoun B.,Laboratoire Of Physico Chimie Des Materiaux | Essehli R.,Ecole des Mines de Nantes | And 5 more authors.
Journal of Alloys and Compounds

The new solid solution series Ba3-xSrx(VO4)2 (0 ≤ x ≤3) has been synthesized and studied by a combination of X-ray powder diffraction and Raman vibrational spectroscopy. This continuous solid solution crystallise in the hexagonal system with R over(3, ̄) m space group. The structure has been determined at room temperature from X-ray diffraction by the Rietveld method analysis. It is formed by a 3D network of (Ba/Sr)(1)(VO4)2 4- layers linked into a crystal network by (Ba/Sr)2+ (2) cations. The vibrational spectra of this crystalline orthovanadate solid solution series are interpreted by means of factor group analysis in terms of space group R over(3, ̄) m (D3 d 5). Assignments of the V-O vibrational stretching and bending modes, as well as some of the external modes, have been made. While all the modes show a monotonous shift as a function of the composition x, a break in the curves of intensities, full width at half maximum and band areas as a function of x is observed and attributed to the statistical distribution of Ba and Sr ions in the same crystallographic sites. © 2010 Elsevier B.V. All rights reserved. Source

Abbou M.B.,Laboratoire Decologie Fonctionnelle Et Environnement | Abbou M.B.,Laboratoire des ressources naturelles et environnement | Rheribi R.,Laboratoire des ressources naturelles et environnement | Haji M.E.,Laboratoire des ressources naturelles et environnement | And 2 more authors.
Physical and Chemical News

Olive mill wastewaters (OMW) are a source of environmental pollution: pollution of surface water and groundwater, soil and air, if they are exposed in OMW evaporation ponds, where the need for treatment or their valorization. The valorization is performed by an application on tomato seeds to evaluate their germination. The germination test performed at different concentrations of OMW, to determine the optimal dose for the germination of tomato seeds, helped to highlight that raw OMW can inhibit germination, while the more diluted OMW more germination is important. Another method is added to the treatment of OMW is electrocoagulation to generate coagulants from the energy supplied by electricity. The treatment improves the properties of the OMW, the more remarkable is that: the color becomes less intense than that of OMW untreated, a reduction of 5-day biological oxygen demand (BOD5), chemical oxygen demand (COD), phosphorus, etc. This treatment has a positive effect on the germination of tomato seeds, which reached 62% compared to diluted OMW at 25%. ©(2014), E-flow PDF Best Edition. All rights reserved. Source

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