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Soliman, Tunisia

Azouzi R.,University Elmanar | Charef A.,University Elmanar | Hamzaoui A.H.,British Petroleum
Environmental Earth Sciences | Year: 2015

Before using Zn-rich sewage sludge in agricultural soil, it is very important to study the behavior of this pollutant and its mobility in semiarid climate to prevent the risk that may pose on the human health. Batch technique was used to study sorption and desorption experiments of zinc onto hydromorphic soil with a loamy texture. Results showed that the effect of pH ranged between 6 and 7.8 on zinc sorption amount was negligible. Whereas the coefficient of distribution Kd at pH = 6 was 1–3 times greater than at pH = 7.8. The increase in temperature from 25 ± 2 to 40 ± 2 °C increased zinc uptake by 4.37–63.2 % and 3.75–27.09 % at pH 7.8 and 6, respectively. The removal of organic matter slightly enhanced zinc sorption at alkaline pH; while it remarkably reduced it at acidic pH suggesting that organic matter effect depended significantly on pH. All sorption data of zinc fitted only the Freundlich equation. Also, the sorption energies (E) calculated from the Dubinin–Radushkevich equation were high implicating that the main process of zinc uptake was chemisorption. Zinc speciation after sorption experiments showed that the added zinc amount was mostly bonded to oxides fraction at alkaline pH and to organic matter at acidic pH. Zinc mobility in the two investigated soil pH values was similar, while its mobility was not very affected by the organic matter removal. The percentage of desorbed zinc (bioavailable) was higher into 0.05 M of ethylenediaminetetraacetic acid (about 20 %) than into distilled water (≤4 %). From the principal component analysis, we deduced that pH was the main factor controlling zinc sorption and the coefficient of distribution Kd was the best parameter that describes the mechanism of zinc retention onto hydromorphic soil. © 2015, Springer-Verlag Berlin Heidelberg. Source

Ben M'Barek Jemai M.,University of Carthage | Karoui-Yaakoub N.,University of Carthage | Sdiri A.,University of Sfax | Ben Salah I.,University of Carthage | And 2 more authors.
Arabian Journal of Geosciences | Year: 2015

Late Cretaceous and Palaeocene clay deposits of the northern Tunisia were studied for potential valorization in clay product manufacturing. To achieve this goal, physicochemical characterization based on multidisciplinary approaches including mineralogy, geochemistry and thermal analyses was carried out. Clay samples collected from the Bir M’Cherga and Tajerouine study sites have undergone chemical analysis by using atomic absorption spectroscopy. The obtained results showed that the studied samples were mainly composed of silica, alumina, calcium and iron oxide. Mineralogical analysis confirmed the results of chemical analysis; it showed the main peaks of quartz, calcite, kaolinite, smectite and illite. Those clay samples were used as natural resources for manufacturing earthenware tiles. Mixtures of clays and dolomites were prepared from the Late Cretaceous and Palaeocene clays and then heated to the desired temperature to obtain different earthenware products. Finally, the prepared clay products were tested via different geotechnical analyses. It was found that the clay percentage needed to be decreased in the starting mixture to enhance the properties of the final products. Those results also indicated that industrial application of both Late Cretaceous and Palaeocene clays of the northern Tunisia could be done, especially for manufacturing clay products. © 2015 Saudi Society for Geosciences Source

Soltani T.,University Elmanar | Chmingui M.,University Elmanar | Marcerou J.P.,French National Center for Scientific Research | Othman T.,University Elmanar
Liquid Crystals | Year: 2014

We present the experimental evidence and theoretical studies of the para-ferroelectric phase transition in the chiral liquid crystal C12HH. The investigated compound presents a large SmC* range. Both microscopic observation and dielectric measurements show thermal hysteresis and coexistence phases at paraelectric (SmA)-ferroelectric (SmC*) phase transition. The thermal hysteresis is analysed in samples with different planar cell thickness. The SmA-SmC* phase transition under electric field is also investigated. Finally, the Landau free energy density is used to analyse the experimental measurements, showing a satisfactory agreement with experimental data. © 2013 © Taylor & Francis. Source

Houatmia F.,University Elmanar | Azouzi R.,University Elmanar | Charef A.,University Elmanar | Bedir M.,University Elmanar
Environmental Earth Sciences | Year: 2016

Oligocene and Mio-Plio-Quaternary siliciclastic deposits constitute the most important deep aquifers of the Kairouanai-Sahel region. Considering the over-exploitation and contamination of the surface groundwater, recourse to use deep groundwater was crucial. These aquifers revealed three major hydrochemical facies: HCO3/Mg, HCO3/Na and SO4/Mg water types. Rock–water interaction showed the main mechanisms are rock weathering and evaporation. Different parameters such as water quality index (WQI), sodium absorption ratio (SAR), percentage of sodium, residual sodium carbonate (RSC), magnesium hazard (MH) and permeability index (PI) were used to evaluate groundwater suitability for drinking and irrigation purposes. Results highlighted that groundwater is unsafe for irrigation based on PI, MH, RSC and salinity diagram. According to the WQI values, 10.25 % of the water samples had good water quality, 69.23 % were considered as poor water, 12.82 % were very poor water and 7.69 % were considered unsuitable for drinking purpose. © 2016, Springer-Verlag Berlin Heidelberg. Source

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