Browsing by Author "Seffah, Karima"

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    Analyse de la durabilité naturelle de différents bois
    (2011) Seffah, Karima
    La présente recherche a comme objectif principal de quantifier les polyphénols dans le chêne par la méthode de Folin-Ciocalteu. Il s'agit d'une méthode analytique biochimique. Le dosage des phénols totaux met on évidence le rôle des extractibles dans la protection naturelle du bois vis-à-vis de lÀattaque fongique. Une étude de la durabilité naturelle des espèces (Pistacia Atlantica , Punica Granatum et Rhus tripartitum) et des extraits de chêne européen par une méthode qualitative nous a permis de conclure que le Punica Granatum fait partie des essences biologiquement résistantes, par rapport aux autres variétés grâce à un taux de phénols élevé
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    A novel spherical hybrid material based on the combination of humic acid/alginate/Algerian Zeen Oak sawdust for removing chromium (VI) from wastewater
    (Elsevier, 2023) Sadoun, Louiza; Benmounah, Abdelbaki; Ait-Ramdane-Terbouche, Chafia; Seffah, Karima; Terbouche, Achour
    A novel spherical hybrid material designed from the combination of humic acid (HA), sodium alginate (Al) and sawdust derived from Algerian Zeen Oak Waste (OS) has been prepared. After optimization of HA/Al/OS mass ratio, the structure of the synthesized hybrid spheres was established using various characterization techniques notably ATR, SEM-EDX, XRD, BET and the point of zero charge (pHpzc). Adsorption tests using this compound were applied to remove chromium(Cr (VI)) from aqueous solutions. The influence of the different parameters such as contact time, pH, temperature, initial metal concentration, and mass of the material were studied. The obtained results revealed that the mass of HA had a significant influence on the formation of the spheres. By varying the ratio of HA/Al/OS (1/16/16 (S1), 1/5/5 (S2), 1/3/3 (S3) and 1/2/2 (S4)), the humic acid allowed a good coating of the hybrid material. The ratio 1/5/5 (S2) was retained for the adsorption study. The efficiency of this material was subsequently tested for the removal of Cr (VI) from aqueous solutions. Optimizing the different experimental parameters allowed to obtain a removal efficiency of over 90 % for an initial Cr (VI) concentration of 60 mg L−1, at pH = 2 and temperature of 353.15 K, using 0.1 g of material. The kinetic study showed that the process of elimination of Cr (VI) followed the pseudo-second order model and well fitted with the Freundlich adsorption isotherm model with R2 value of 0.99 and a low value of χ2 (2.88). A maximum adsorption capacity of 50.328 mg.g−1 was determined by the Langmuir isotherm model. The hybrid spheres showed good regeneration efficiency even after four adsorption-desorption cycles. The thermodynamic study (ΔS = 0.091 kJ mol−1 K−1, ΔH = 24.427 kJ mol−1 and ΔG° = −2.883 kJ mol−1 at 298.15 K) revealed that the adsorption process was spontaneous, favorable and endothermic with a physisorption phenomenon. Finally, the adsorbent was successfully applied to real wastewater contaminated with chromium. This application has proved high removal efficiency of Cr (VI) and a yield of 94.31 % was obtained at 40 °C.
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    Pecan shells-based activated carbon for the removal of copper metal ions: optimization of the adsorption process using a full factorial design
    (Taylor & Francis, 2024) Seffah, Karima; Lakehal, Imane; Ouriache, Hadjer; Sadoun, Louiza; Badis, Dalila; Khenchali, Karim; Bendhina, Abdellah; Nadji, Halima; Ghernaout, Djamel
    This work investigates the removal of copper ions (Cu2+) from an aqueous solution by adsorption onto the surface of activated carbon (AC) produced from pecan shells. The research aims to identify a feasible and effective route for cleaning the wastewater from Cu2+. Chemical activation was carried out using sodium hydroxide. The AC physicochemical properties were characterised by scanning electron microscopy, Fourier-transform infrared, X-ray diffraction, and Brunauer-Emmett-Teller for measuring its specific surface area. To obtain a suitable removal of this metal ion, four physicochemical factors, including the contact time (120–360 min) the adsorbent dose (10–100 mg), initial concentration (10–50 mg/L), and pH (2–6) were optimised using the 24-full factorial design approach. A quadratic regression model representing the capacity of Cu2+ adsorption (Qe) was developed and validated by the analysis of variance. This approach was used to determine independent factors’ main and interaction effects on adsorption equilibrium capacity. The results consolidate similar studies showing that all the factors were significant, and the interactions among the factors were also significant. The optimum conditions for circumscribed fractional factorial design were adsorption time (120 min), adsorbent amount (10 mg), initial metal ions (50 mg/L), and pH 6. The pseudo-first-order model correctly describes the adsorption kinetics with Qe, reached 51.41 mg/g. Modeling adsorption isotherms showed that the Freundlich model adequately describes the adsorption process.