Génie Chimique

Nombre total de résultats : 51
Pertinence Titre A-Z Plus récents Plus anciens
10 25 50
Année de publication
et

Etude de l’élimination des colorants en solution sur un charbon actif issu du broyage cryogénique des pneus usagés

OULD BRAHIM Insaf (2012)
Mémoire de magister

The synthesis of an activated carbon by chemical activation with phosphoric acid from powder from the cryogenic grinding of a used tire confirmed by infrared analysis the introduction of surface functions, SEM analysis mesoporous nature of coal active prepared which has a specific surface area of 356 m² / g. The experimental approach is to conduct in aqueous solutions, adsorption experiments in batch system of two cationic dyes: Methylene blue and Methyl green is widely used in the textile industry of Algeria. For this, we conducted an experimental study of adsorption kinetics by examining the effect of some important operating parameters affecting the decolorizing power of charcoal used, in particular, the contact time, pH of the solution, the temperature , the initial concentration of dye and the mass of activated carbon. The study of the influence of contact time showed an equilibrium time of 114 min for MB and 80 minutes for the VM. The application of classical models of adsorption isotherms indicates a good description of experimental results by the Langmuir model for both dyes with maximum capacities of 28.87 mg / g for MB and 33.33 mg / g for the VM . Through the kinetic study conducted, it turned out that in the process of adsorption of two dyes on activated carbon prepared, several mass transfer mechanisms involved, namely the external mass transfer, surface reactions that are pseudo-first order for both systems, and internal diffusion. The study of the influence of temperature was used to estimate the thermodynamic quantities which have shown that the adsorption is spontaneous, exothermic and endothermic for MB for the VM Voir les détails

Mots clés : adsorption, activated carbon, Langmuir, Freundlich

Application d’un procédé AD-OX (Adsorption-Oxydation) pour le traitement des colorants alimentaires en milieu aqueux

OULD BRAHIM Insaf (2018)
Thèse de doctorat

L a première étape de ce travail est dédiée à l’étude de la dégradation sonocatalytique en présence ou en l’absence du peroxyde d’hydrogène H2O de deux colorants alimentaires largement utilisés dans les industries agroalimentaires et 2pharmaceutiques en Algérie. Le travail est réalisé en suspension aqueuse en présence de ZnO. La décoloration de la suspension est effective après un traitement par le procédé US-ZnOH2O de 2 min pour le E132 et de 30 min pour le E127, et s’accompagne d’une minéralisation partielle de 50.20% pour le E127 et de 76% pour le E132 pour une concentration initiale en colorants alimentaires égale à 50 mg L2-1. Afin de déterminer le mécanisme général de la sonocatalyse et plus tard de la photocatalyse, une étude est consacrée à l’évaluation de l’efficacité photocatalytique du catalyseur commercial, l’oxyde de Zinc, ZnO. Ce travail nous a permis d’estimer les taux d’adsorption et l’étude des isothermes d’adsorption des colorants étudiés sur le catalyseur ZnO, en l’absence du rayonnement UV ou US. Nous avons en outre, examiné l’influence de quelques paramètres sur les différents procédés utilisés dans cette étude. La seconde partie est consacrée à la caractérisation de l’oxyde de Zinc avant et après le procédé US-ZnO-H2O, par différentes techniques, MEB, DRX et FTIR. La dernière partie de cette thèse a l’étude photocatalytique des deux colorants alimentaires, E127 et E132 par les procédés UV-ZnO et UV-ZnO-H22O. La décoloration de la suspension est effective après un traitement par le procédé UV-ZnO de 240 min pour le E132 et de 180 min pour le E127, et de 60 min pour le E127, et de 10 min pour le E127 pour le procedé UVZnO-H2O22 pour une concentration initiale en colorants alimentaires égale à 50 mg L. Le modèle de Langmuir-Hinshelwood est adéquat pour décrire la cinétique de dégradation des colorants alimentaires en utilisant ces procédés. Pour le mélange binaire des deux colorants, nous avons atteint un rendement d’élimination égal à 64% au bout de 180 min pour un mélange de 90% E127+10% E132. Enfin une étude comparative entre les différents procédés utilisés UV, US, UV-ZnO, USZnO,US-ZnO-H2O2 et UV-ZnO-H2O a été effectuée. Voir les détails

Mots clés : Sonocatalyse, ultrason, MEB, FTIR, DRX

Discoloration of Azo Dye Solutions by Adsorption on Activated Carbon Prepared from the Cryogenic Grinding of Used Tires

OULD BRAHIM Insaf, BELMEDANI AHMED, Belgacem Ahmed, Hadoun Hocine, SADAOUI ZAHRA (2014)
Article de journal

This present work reports a study about the adsorption of cationic dye (Methylene blue) by activated carbon prepared from the cryogenic grinding of used tires. Characterization of the obtained activated carbon by chemical analysis, FTIR and SEM, was studied and resumed that the activated carbon was mesoporous. The effect of various experimental parameters such as contact time, solution pH, adsorbent dose and dye concentration, on the dye adsorption uptake on the activated carbon has been investigated using batch adsorption experiments. According to the experiments results, it was shown, that equilibrium was achieved in less than 114 min. The effect of pH investigated for values ranging from 2 to 11, showed maximum adsorption for pH 11. The equilibrium adsorption isotherms models of Langmuir, Freundlich and Dubinin-Radushkevich, were tested for the quantitative description of the dye adsorption. The Langmuir isotherm provided the best fit for dye adsorption onto the prepared activated carbon and the maximum adsorption capacity was found to be 30.21 mg.g-1. The results show that the produced activated carbon from used tire is an alternative low-cost adsorbent for removing dyes from solutions.Voir les détails

Mots clés : adsorption, FTIR, SEM

Degradation of C.I. Acid Red 51 and C.I. Acid Blue 74 in Aqueous Solution by Combination of Hydrogen Peroxide, Nanocrystallite Zinc Oxide and Ultrasound Irradiation

OULD BRAHIM Insaf, MOHAMED BELMEDANI, Ahmed HADDAD, HOCINE HADOUN, AHMED BELGACEM (2018)
Article de journal

Journal of Advanced Oxidation Technologies2018; 21(1)www.jaots.netDOI:10.26802/jaots.2017.0022Journal of Advanced Oxidation Technologies 2018; 21(1)Article ID-20170022Article:Degradation of C.I. Acid Red 51 and C.I. Acid Blue 74 in Aqueous Solution by Combination of Hydrogen Peroxide, Nanocrystallite Zinc Oxide and Ultrasound IrradiationInsaf Ould Brahim*1,3, Mohamed Belmedani1,Ahmed Haddad3, Hocine Hadoun2,Ahmed Belgacem11Laboratory of transfer phenomena, Faculty of Mechanical and Processes Engineering, University of Sciences and Technology Houari Boumediene, BP n 32 El Alia bab ezzouar 16111 Algiers, Algeria2Nuclear Research Center of Algiers, 2 Bd Frantz Fanon, 16035, Algiers, Algeria3Research Center in Industrial TechnologiesCRTI, P.O.Box 64, Cheraga 16014 Algiers, Algeria *iouldbrahim@gmail.comPhone: 00213-20-77-67Fax: 00213-21-34 -20-19AbstractThis study illustrates the degradation of food dyes, C.I. Acid Red 51 (erythrosine E127) and C.I. Acid Blue 74 (indigo carmine E132) by sonocatalysis using an ultrasonic frequency of 37 kHz and a power of 150 W in the presence of heterogeneous catalysts ZnO and peroxide hydrogen (H2O2). The adsorption process for the two dyes on the ZnO nanocrystalline which satisfies the Freundlich model appears not effective because the elimination of the two food dyes does not exceed 35%. In order to improve the removal, the sonocatalytic process (AD-OX) has been investigated. At this purpose, effect of operating parameters such as initial dye concentrations, H2O2(0-0.75M) and initial pH on the sonochemical degradation was investigated. It was observed that when the adsorption-catalysis was assisted by the ultrasonic and H2O2 a considerable yields has been achieved and about 86% and 97% of E127 and E132 were removed for 10 mg L-1and 50 mg L-1respectively. To understand the behavior of dye degradation, structure of the zinc catalyst before and after the sonocatalytic process was characterized by meanX-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM).Results showed thatthe ZnO particles before and after sonocatalysis were crystallized in the hexagonal wurtzite phase and the size distribution indicates that most of the particles are in the range of 300 and 600 nm. Finally, ADMI and COD analysis were performed in order toquantify the residual color in solution and evaluate the efficiency of the dye mineralization. Results showed that the treatment of food dyes by US-ZnO-H2O2process increased color degradation (ADMI)and mineralization efficiency (COD) by more than 50% and 76% respectively.Voir les détails

Mots clés : Advanced oxidation process, sonocatalysis

MANUFACTURING NANOSTRUCTURED AND MICROSTRUCTURED CHITOSAN PREPARED BY MILLING SHRIMP SHELL

Belmedani Mohamed, Hadoun Hocine, Belgacem Ahmed, Haddad Ahmed (2019)
Article de conférence

Nano-products are of great interest in the field of pharmaceutical, corrosion, medecine and engineering. This research aimed to produce nano-chitosan. Nanocrystallite. Shrimp shells have been prepared by using a high-energy planetary ball with an optimal rotational speed.The raw material was subjected to standard chemical processing for chitin extraction, followed by deacetylation to obtain nanocrystallite chitosan, which is characterized by Scanning Electron Microscope SEM and Fourier Transform Infrared Spectrometry FT-IR.Voir les détails

Mots clés : Shrimp shell, Planetary milling, chitosan, SEM, FT-IR, XRD

Copper removal in solution by sawdust: kinetic and thermodynamic study

T. CHOUCHANE, A. Boukari, A. Bendjama, O. Khireddine, S. chibani (2018)
Article de journal

This study presents the results obtained when okoumé sawdust is used for the removalof copper contained in wastewater. The tests show that one gram of sawdust can fix29.56 mg of copper, according to the Langmuir model with kinetics of the pseudo firstorder where the time of the pseudo equilibrium is reached after 40 minutes of agitation.The elimination is envisaged in batch mode, at 20 ° C, a stirring speed of 200 rpm, atpH value of 4.4 and a particle size between 500 ≤ Ø < 700μm. Measured results alsoreveal that external diffusion controls the speed of the overall process of adsorption anddiffusion into the pores is not the only mechanism limiting kinetics. The thermodynamicstudy shows that this sorption is spontaneous , exothermic and that no changes havebeen made in the structure of the sawdustVoir les détails

Mots clés : Cooper, adsorption, sawdust, water, pollution

Développement d'électrodes modifiées à base de films minces électroactifs. Application à la détection électrocatalytique

Cherif DEHCHAR (2017)
Thèse de doctorat

Au travers de ce projet de thèse, nous nous sommes fixés pour objectif la mise au point de nouveaux matériaux fonctionnels appliqués en électroanalyse. Il s'agit de développer de nouvelles électrodes modifiées ayant de grandes performances analytiques par dépôt de films minces métalliques à base d'argent ou de cuivre sur un substrat non-conducteur de verre époxy ; ou encore, par une dispersion de microparticules d'un métal noble à propriétés catalytiques, tel que le palladium, sur la surface d'un film polymère conducteur, tel que le polypyrrole électrogénéré sur silicium. Pour ce faire, nous avons opté pour la technique de dépôt par bain chimique afin de réaliser les dépôts métalliques d'argent et de cuivre ; et pour les méthodes électrochimiques de déposition, à savoir l'électropolymérisation et l'électrodéposition pour synthétiser les films composites palladium-polypyrrole. L'étude de la réactivité électrochimique des électrodes élaborées a pour objectif d'envisager leur utilisation comme capteurs voltammétriques dédiés à la détection de différentes substances d'intérêt pharmaceutique ou biomédical, telles que le peroxyde d'hydrogène, le formaldéhyde et l'acide ascorbique. La démarche que nous avons entreprise afin d'améliorer les caractéristiques analytiques de nos électrodes consiste à mettre en synergie les propriétés physicochimiques des dépôts et la réactivité électrochimique des électrodes élaborées en étudiant l'effet des paramètres de synthèse les plus influents de sorte à maîtriser leur influences sur les performances électrocatalytiques des électrodes, ainsi pour assurer une bonne reproductibilité des mesures. Voir les détails

Mots clés : Argent, capteur, Electrode modifiée, couches minces, composites, Polypyrrole

Computation Of The Energy Density Of The Adsorption Sites By Inverse Gas Chromatography

BOUHANK Antar, BENCHEIKH Lahcene (2017)
Article de conférence

Inverse Gas Chromatography (I.G.C) technique can be used to determine the adsorption properties of the stationary phase of various materials. The problem is formulated in terms of an integral equation where the unknown is the energy density. The integral equation is a Fredholm integral equation of the first kind. Generally, integral equations cannot be solved analytically. Resort is often made to numerical methods of solutions. The kernel of the integral equation is the adsorption model. For some special models, a solution in a closed form was obtained. Some results are presented.Voir les détails

Mots clés : Inverse gas chromatography, adsorption energy, adsorption models, integral equation

Réactivité électrochimique des électrodes composites (polymères conducteurs, catalyseurs) appliquées à l’électrocatalyse et à la dépollution.

Abderrazak HAMAM (En préparation)
Thèse de doctorat

The aim of this work is to synthesize polypyrrole (PPy) films on nonconducting cellulosic substrateand modified by copper oxide particles for use in the nitrate electroreduction process. Firstly, thechemical polymerization of polypyrrole onto cellulosic substrate is conducted by using FeCl3 as anoxidant and pyrrole as monomer. The thickness and topography of the difierent PPy films obtainedwere estimated using a profilometer apparatus. The electrochemical reactivity of the obtainedelectrodes was tested by voltamperometry technique and electrochemical impedance spectroscopy.Secondly, the modification of the PPy film surface by incorporation of copper oxide particles isconducted by applying a galvanostatic procedure from a CuCl2 solution. The SEM, EDX and XRD analysis showed the presence of CuO particles in the polymer films with dimensions less than 50 nm.From cyclic voltamperometry experiments, the composite activity for the nitrate electroreductionreaction was evaluated and the peak of nitrate reduction is found to vary linearly with initial nitrateconcentration. Voir les détails

Mots clés : Polypyrrole, cellulosic, CuO, electrocatalysis, Nitrate

ETUDE DES PROPRIETES PHYSICO-CHIMIQUES DES OXYDES DE TITANE OBTENUS PAR VOIE SOL-GEL

Abderrazak HAMAM (2012)
Mémoire de magister

In this work, simple and composite xerogels based alcoxydes of titanium and silicon to knowing the titanium tetraisopropoxide Ti[OCH(CH3)2]4 , tetramethoxysilane Si(CH3)4 : were prepared by sol-gel processing. The solutions were prepared in acid, basic and neutral mediums. The gelation of these solutions whereas it varies between 5 hours and 9 days for the simple xerogels whiles it varies between 3-9 days for the composite xerogels. The gel obtained was dried at ambient temperature. The microstructural evolution of the simple and composite xerogels was followed by the differential thermal analysis (DTA), thermogravimetrie (TG) and by Fourier transforms infrared spectroscopy (FTIR). Voir les détails

Mots clés : : Sol-Gel, Xerogels, titanium, composite, thermal analysis, FTIR