Browsing by Author "Khemmari, Fariza"

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    A comparative study of raw and treated peach stones for the adsorption of hexavalent chromium: characterization, kinetic and thermodynamic modelling
    (2018) Khemmari, Fariza; Benrachedi, K.
    In the last years, much attention has been focused on the use of low-cost adsorbents for the removal of heavy metals from wastewater. The present study consists of comparing the adsorption of hexavalent chromium in aqueous solutions by two adsorbents: raw peach stones (RPS) and peach stones activated carbon (PSAC). The characterization of the adsorbents was done by using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Comparative study was carried out using adsorption parameters such as contact time, adsorbent dose and solution pH in a batch system. Results show that pH is key parameter for adsorption optimization. The time necessary to attain adsorption equilibrium was found 120 min for PSAC in the pH range 2-5.6 and 240 min for RPS at pH 2 with maximum removal percentage greater than 97% for both adsorbents. The adsorption process followed the pseudo-second order kinetics. Thermodynamic parameters revealed the spontaneous and endothermic nature of the adsorption process for both adsorbents. Investigations carried out proved that RPS and PSAC are good potential adsorbents for the treatment of toxic hexavalent chromium
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    Etude de l’élimination du chrome(VI) par adsorption sur des déchets agro-aliment cas des noyaux de pêche
    (2019) Khemmari, Fariza
    L'objectif de cette étude consiste à une valorisation des noyaux de pêches et leur application dans l’élimination du chrome(VI). Deux matériaux, à savoir, les noyaux de pêche à l’état brut (NPB) et les noyaux de pêche modifiés par une carbonisation suivie d’une activation chimique (NPCTA) ont été préparés. La caractérisation de ces matériaux a été réalisée en utilisant la spectroscopie infrarouge IR, la microscopie électronique à balayage (MEB) et la diffraction des rayons X (DRX). Les taux d’humidité, les taux de cendres et les points isoélectriques (pHzpc) ont été également déterminés. Les propriétés sorbtives des deux matériaux ont été comparées en fonction de plusieurs paramètres tels que le temps de contact, la dose d'adsorbant, le pH de la solution, la concentration du métal, la vitesse d’agitation, et la température du milieu dans un système discontinu. Les résultats expérimentaux obtenus montrent que le pH est un paramètre important et déterminant pour l'optimisation de l'adsorption. Le temps nécessaire pour atteindre l'équilibre d'adsorption a été trouvé 120 min pour NPCTA dans l'intervalle de pH 2-5,6 et 240 min pour NPB à pH 2 avec une efficacité d'élimination supérieure à 97% à une concentration du chrome de 30 mg/L, au-delà de cette concentration le temps d’équilibre est prolongé jusqu’à 360 min. Les paramètres thermodynamiques ont révélé la nature spontanée et endothermique du processus. L’étude d’adsorption du Cr(VI) en mode dynamique sur les noyaux de pêche bruts, a montré un meilleur rendement d’adsorption à un faible débit (1,5ml/min) et une hauteur du lit de 3cm
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    Reduction of turbidity and chromium content of tannery wastewater by electrocoagulation process
    (Water Environment Federation, 2018) Ziati, Mounir; Khemmari, Fariza; Aitbara, Adel; Hazourli, Sabir
    The present study is carried out to remove chromium and turbidity from tannery wastewater using the electrocoagulation process with aluminum electrodes. This experimental study is carried out using a batch system. The applied pilot comprises a reactor containing two parallel metal electrodes (Al). The latter are connected as monopolar, and a different potential is applied between them. Several working parameters, such as applied potential difference, electrolysis time, active electrode surface, interelectrode distance, and the pH of the medium have been studied to achieve higher removal efficiency. The treatment reached a maximum reduction of 99% for turbidity and 93% for chromium under the following conditions: 15 V applied potential difference, 45 cm 2 electrode surface, 1 cm interelectrode distance, pH 6.1 raw water, and a contact time of 90 min. Given the treatment efficiency obtained in this study, electrocoagulation process has the potential to be used for the cost-effective removal of wastewater pollutants.
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    Removal of chromium from tannery wastewater by electrosorption on carbon prepared from peach stones : effect of applied potential
    (2017) Ziati, Mounir; Khemmari, Fariza; Kecir, Mohamed; Hazourli, Sabir
    The objective of this study is the removal of chromium from tannery wastewater by electrosorption on carbon prepared from lignocellulosic natural residue "peach stones' thermally treated. The followed steps for obtaining coal in chronological order were: cleaning, drying, crushing and finally its carbonization at 900°C. The characterization of the carbon material resulted in properties comparable to those of many coals industrially manufactured. The study of the dynamic adsorption of chromium on the obtained material resulted in a low removal rate (33.7%) without applied potential. The application of negative potentials of -0.7 V and -1.4 increases the adsorption of chromium up to 90% and 96% respectively. Whereas a positive potential of +1.4V allows desorption of the contaminant of 138%
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    Removal of polyphenols from olive mill wastewater by adsorption on activated carbon prepared from peach stones
    (Cartimex, 2017) Ziati, Mounir; Khemmari, Fariza; Cherifi, Ouiza; Didouche, Yasmina-Fadila
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