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Marzougui K.,University of Monastir | Marzougui K.,Research Laboratory Energy and Matter | Farah K.,Research Laboratory Energy and Matter | Farah K.,University of Sousse | And 2 more authors.
Ceramics International | Year: 2016

A new hybrid monolithic silica xerogel containing sucrose has been synthesized via the sol-gel method. The resulting sucrose silica xerogels were exposed to gamma radiation with a dose in the range of 10-100. kGy. The effect of gamma rays on the physical and structural properties of sucrose silica xerogels was investigated by Fourier transform infrared spectroscopy (FTIR) and UV visible spectroscopy. The results of FTIR spectroscopy show that the irradiation process causes changes in the network's structure by inducing defects. The UV visible spectra present three main band defects; E' center, Non-Bridging Oxygen Hole center (NBOHC) and carbonyl radicals in irradiated sucrose silica xerogel samples. Additionally, the results show that the values of optical band gap energy depend on irradiation. Therefore, generated defects suggest that the behavior of sucrose silica xerogels was modified from an insulator (Eg=5.82. eV) to a semiconductor (Eg=3.16. eV) under gamma irradiation. © 2016 Elsevier Ltd and Techna Group S.r.l. Source

Haddad K.,Water Research and Technologies Center | Jellali S.,Water Research and Technologies Center | Jaouadi S.,Water Research and Technologies Center | Benltifa M.,Water Research and Technologies Center | And 2 more authors.
Comptes Rendus Chimie | Year: 2015

Phosphorus removal from synthetic solutions by raw and calcined powdered marble wastes (RPMW and CPMW) has been investigated in batch mode under different experimental conditions. The results showed that RPMW and CPMW have high removal efficiencies, especially in acidic media. The maximum phosphorus removal capacities were evaluated to 103.9 and 181.2 mg g 1 at an initial pH and an aqueous concentration of 5 and 350 mg L-1, respectively. Phosphorus removal by RPMW occurred mainly through adsorption. However, for CPMW, phosphorus was removed not only by adsorption, but also by precipitation as calcium phosphate complexes. Specific analyses using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy confirmed that this precipitate is most probably hydroxyapatite. On the other hand, CPMW have demonstrated an important ability in removing phosphorus from highly concentrated dairy wastewater (C0,P = 1000 mgL-1) since only one dosage of 10 gL-1 was enough to ensure more than 97% of phosphorus removal. © 2014 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved. Source

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