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Marzouk I.,UR Traitement et Dessalement des Eaux | Dammak L.,ICMPE | Hamrouni B.,UR Traitement et Dessalement des Eaux
Water Environment Research | Year: 2013

In this study, the removal of chromium (VI) by adsorption on activated alumina was investigated and the results were fitted to Langmuir, Freundlich, Dubinin-Redushkevich, and Temkin adsorption models at various temperatures. The constants of each model were evaluated depending on temperature. Thermodynamic parameters for the adsorption system were determined at 10, 25 and 40°C. (ΔH° = ⋯ 21.18 kJ.mol-1; δG° = ⋯ 8.75 to ⋯ 7.43 kJ.mol-1 and ΔS° = ⋯ 0.043 kJ.K-1.mol-1). The obtained values showed that chromium (VI) adsorption is a spontaneous and exothermic process. The kinetic process was evaluated by first-order, second-order and Elovich kinetic models. Source


Marzouk I.,UR Traitement et Dessalement des Eaux | Hannachi C.,UR Traitement et Dessalement des Eaux | Dammak L.,ICMPE | Hamrouni B.,UR Traitement et Dessalement des Eaux
Desalination and Water Treatment | Year: 2011

The removal of chromium (VI) from aqueous solutions by activated alumina has been investigated as a function of solution pH, initial chromium concentration, adsorbent dose of activated alumina and temperature. The pH and the adsorbent dose of activated alumina are the most significant parameters affecting chromium (VI) adsorption. The chromium concentrations were analyzed by reaction with 1,5-diphenylcarbazide. This method has been validated according to the French standard XPT-90-210. In order to optimize the effect of the main parameters and their mutual interaction for the adsorption process, a full factor design of the type nk has been used. Thus, the total number of trial experiments needed for an investigation is 24. The Freundlich and Langmuir models have been applied and the equilibrium adsorption data were found to best fit the Freundlich and Langmuir adsorption isotherm. A comparison of kinetic models applied to the adsorption of chromium (VI) on activated alumina was evaluated for the first-order and the second-order models respectively. Results show that the second-order kinetic model was found to correlate the experimental data well. © 2011 Desalination Publications. Source


Guesmi F.,UR Traitement et Dessalement des Eaux | Hannachi C.H.,UR Traitement et Dessalement des Eaux | Hamrouni B.,UR Traitement et Dessalement des Eaux
Desalination and Water Treatment | Year: 2010

The effect of the temperature variation on ion exchange equilibrium between an anion exchange membrane and solutions of electrolytes containing the most dominant anions of natural waters (CI-, NO- 3 and SO2- 4) was studied. All experiments were carried out at 0.3 mol l-1. AMX membrane experimented in this work is a commercial product provided by TOKUYAMA SODA. Humidity percentage and ion exchange capacity were determined. Ionic exchange isotherms for the binary systems (CI- /NO-3), (CI- /SO2- 4) and (NO- 3 / SO2- 4) were established at different temperatures from 283 to 313 K. At 283 and 298 K, the affinity order was: CI- >NO- 3 > SO2- 4This order was NO- 3 >CI- >SO2- 4 at 313 K. Selectivity coefficients Kj i and thermodynamic equilibrium constants Koj i calculated for uni-univalent and uni-bivalent ions exchange reaction system increase with increasing temperature. Thermodynamic parameters such as standard free enthalpy change, standard enthalpy change, and standard entropy change were calculated. Ion exchange equilibrium at temperatures 283, 298 and 313 K of studied binary systems are found to be endothermic processes. Standard deviations calculated for ion exchange selectivity coeffi cient and thermodynamic equilibrium constant were lower than 5% at studied temperatures. © 2010 Desalination Publications. All rights reserved. Source


Bouguerra W.,UR Traitement et Dessalement des Eaux | Barhoumi A.,Gafsa University | Ibrahim N.,Gafsa University | Brahmi K.,UR Traitement et Dessalement des Eaux | And 2 more authors.
Desalination and Water Treatment | Year: 2015

Lead is a priority substance in the framework of the European water policy (Water Framework Directive 2000/60/EC and Water Environmental Quality Standards Directive 2008/105/EC), since it presents a significant risk to biota and humans, given its persistence, toxicity and bioaccumulation characteristics. This study is devoted to focus on lead removal by means of electro coagulation (EC). The performance of EC process with aluminium electrodes for removal of lead on laboratory electrochemical cell was studied. The effects of various parameters such as electrochemical treatment time, solution pH, current density (J), electrolyte concentration and electrical energy consumption on the percentage of lead removal were investigated. The optimum conditions for EC process were identified as pH 5, current density of 2.67 mA cm−2 and electrolyte concentration of 0.5 g L−1. Effect of EC reactor design parameters such as the surface-area-to-volume ratio and the distance between electrodes were investigated. The obtained experimental results showed that optimal lead removal was achieved with distance between electrodes of 0.5 cm and surface-area-to-volume ratio (S/V) of 11.2 m−1. Under optimal conditions with 30 min treatment, the lead removal efficiency was about 99%. The optimal operating conditions can achieve efficient removal in a relatively short reaction time and low energy consumption. In the light of these results, EC could be regarded as a potential technique for the treatment of industrial wastewater containing lead. © 2015 Balaban Desalination Publications. All rights reserved. Source


Hannachi C.,UR Traitement et Dessalement des Eaux | Guesmi F.,UR Traitement et Dessalement des Eaux | Marzouk I.,UR Traitement et Dessalement des Eaux | Hamrouni B.,UR Traitement et Dessalement des Eaux
Desalination and Water Treatment | Year: 2010

Ion exchange membranes are receiving considerable attention and are successfully applied for desalination and for treating industrial effluents. They are efficient tools for the concentration or separation of food and pharmaceutical products containing ionic species. Extensive work has been reported on synthesis, characterization, properties and applications of these membranes. In this work ion exchange isotherms for the binary Na+/K+, Li+/K+, and Li+/Na+ were established at various ionic strengths, using CRP cationic membrane. All experiments were carried at 25 °C, by setting the ionic strength in the range of I = 0.1-1.5 mol · l-1. All the results given by this membrane were compared with those obtained, in the same conditions, with CMX membrane. For the two membranes, up to ionic strength 1.5 mol · l1 affinity order was: K+ > Na+ > Li+. Selectivity coefficients K K+ Na+ KK+ Li+ and K Na+ Li+ for homogenous CMX membrane were greater than those determined for heterogeneous CRP membrane. For low ionic strength till I = 0.2 mol · 11, these selectivity coefficients decrease strongly and tend asymptotically to unity for higher values of I. The product of selectivity coefficients K Na+ Li+·K K+ Na+·K Li+ K+ were always close to unity. © 2010 Desalination Publications. All rights reserved. Source

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