Génie Chimique

Nombre total de résultats : 56
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STUDY OF THE ELIMINATION OF PHENOL BY ADSORPTION ON AN ALGERIAN DIATOMITE

A. BALASKA, H. MERADI, R. AYACHE, M. SELAMETTE, M-H. SAMAR, L. ATOUI, M. ABBASSI  (2010)
Article de conférence

The phenol and its derivatives are compounds which are found in several types of industrial wastewater such as: rejections of painting, paper, plastics, oil and gasoline, steel, the textile, pharmaceutical industry and the wood industry. They are toxic for the man and for and the other aquatic environments; of which, a small concentration of phenol in the medium (2.5 mg/l) causes an unpleasant odor of drinking water.In this study, we used the diatomite of the deposit of Sig (west of Algeria) like an adsorbent to eliminate this type of organic pollution. The several techniques were used to characterize this material and explain the morphology and the composition of this powder. The porous structure of the raw diatomite is clearly observed in the MEB, the diffraction of X-rays presents more than 80% of amorphous state and the analysis by FRX shows that the powder contains more than silica 65 %. The adsorption of phenol was carried out on the raw diatomite and modified by chemical activation; we were used the sulphuric acid 5 mol/l.The kinetics and the isotherms of adsorption were established for the two adsorbents. The influence of some parameters such as the pH of the medium and the initial concentration of the pollutant on the process of adsorption was also evaluated. Voir les détails

Mots clés : Phenol, diatomite, characterization, adsorption

Nanostructured CuO directly grown on copper electrochemically: synthesis and characterization

A.HAMAM, M.Mokhtari, D.OUKIL, S.Bouhouche, L.MAKHLOUFI  (2015)
Article de conférence

Nanostructured CuO was directly grown on copper foam. The Cu foil was modified electrochemically by Cyclic voltammetry (CVs) a three electrode cell with Cu foam working electrode, platinum foil counter electrode and saturated calomel reference electrode in 5 M KOH solution,after reaction for Cu electrooxidation at room temperature. The shiny Cu foil surface turned to complete black after the reaction. The obtained electrode (denoted as CuO/Cu). The morphology and structure of the CuO were examined by X-ray diffraction spectroscopy. Voir les détails

Mots clés : Copper substrate, cyclic voltammetry

PREPARATION DE NANO-COMPOSITES A MATRICE POLYMERE CDTE EN VUE D’PPLICATIONS DANS LE PHOTOVOLTAIQUE

Ait Atmane Abdenour, Chellouche Azeddine, Hamam Abderrazak  (2014)
Article de conférence

Dans ce travail, nous avons élaboré des nanocompsites DdTe-PMMA (film et pastille),Cdte-PS (film et pastille).Les résultats de la caractérisation par diffraction des rayons X sur les nanocomposites étudiés ont montré l’incorporation des nanocristallites de CDTe dans les deux matrices.Les analyses par spectrométrie Raman et par spectroscopie infrarouge à transformée de Fourier des nanocomposites préparés ont révélé l’existence des modes propres de CdTe. La caractérisation par transmission optique dans la gamme UV-Vis-proche infrarouge amontré que l’incorporation des cristallites de CdTe diminue la transmission et élargit la gamme de transparence des matrices hotes.le spectre de la photoluminescence d’une pastille de CdTe-PS a montré une émission intense et étroite mettant en évidence l’élargissement du gap optique du nanocomposite et a confirmé l’effet du confinement quantique. Voir les détails

Mots clés : Nano-composites, matrices polymère, films, PMMA, PS, CdTe.

Phenol photodegradation process assisted with Wells–Dawson heteropolyacids

Adel BALASKA, Mohamed Elhadi Samar, Azzeddine GRID  (2015)
Publication

This work aims to investigate the catalytic properties of the heteropolyacids (HPAs) withinphotocatalytic process. Photocatalytic degradation of phenol in aqueous solution was performedusing Wells–Dawson HPAs as catalysts under UV-illuminated condition at 254 nm.The effects of various parameters such as, concentration of catalyst, initial pH, and initialphenol concentration on the performance of photocatalytic process have been investigatedto obtain the efficient and durable catalysts and determine the better reaction conditions.The kinetics and the efficiency of phenol degradation were determined by various analyticaltechniques, such as HPLC and TOC. The results show that the photocatalytic degradationefficiency increases with decreasing pH and the optimum pH is 2 for both catalysts. Thephotodegradation follows pseudo-first-order kinetics with rate constants k = 8.56 × 10−2 and 9.94 × 10−2 min−1 for iron- and vanadium-substituted HPAs, respectively. Voir les détails

Mots clés : Well-Dawson HPA, Homogeneous catalysis, Phenol photodegradation, UV irradiation

Pillared clays as catalysts for methyl parathion removal by advanced oxidation processes

Salim Kouraichi, Mohamed El-Hadi SAMAR, Mostefa ABBESSI, Hassane BOUDOUH, Adel BALASKA  (2015)
Publication

A natural bentonite from Mostaganem in Algeria was modified by intercalation with polyoxocationic solutions (Al•Fe, Al•Co, Al•Cu, Al•Fe•Cu or Al•Fe•La). The modification of the bentonite occurred via pillaring by ionic exchange with these solutions. The addition of these solutions led to the formation of pillared clays with important catalytic properties in environmental impact reactions. The structural and textural properties of materials calcined at 500 °C were determined by several techniques: X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and N2 adsorption–desorption analysis. The pillared clays were then used as a Fenton-type heterogeneous catalyst for the heterogeneous sono-Fenton process for the oxidation of methyl parathion in water. The catalytic tests revealed the activity of the introduced iron species and the promoter effect of lanthanide or copper on the catalytic activity of these species. The sono-Fenton method showed promising results for the degradation of methyl parathion when compared with the Fenton method. Therefore, the sono-Fenton method can be a viable alternative technology to the existing methods for treating methyl parathion in wastewater. Voir les détails

Mots clés : Advanced oxidation process, Pillared clay, Sono-Fenton, Methyl parathion pesticide, Wastewater treatment

Phenol photodegradation process assisted with Wells- Dawson heteropolyacids

Adel BALASKA, Mohamed Elhadi Samar, Azzeddine GRID  (2015)
Publication

This work aims to investigate the catalytic properties of the heteropolyacids (HPAs) within photocatlytic process. Photocatalytic degradation of phenol in aqueous solution was performed using Wells-Dawson HPAs as catalysts under UV-illuminated condition at 254 nm. The effects of various parameters such as, concentration of catalyst, initial pH and initial phenol concentration on the performance of photocatalytic process have been investigated to obtain the efficient and durable catalysts and determine the better reaction conditions. The kinetics and the efficiency of phenol degradation were determined by various analytical techniques, such as HPLC and TOC. The results show that the photocatalytic degradation efficiency increases with decreasing pH and the optimum pH is 2 for both catalysts. The photodegradation follows pseudo first-order kinetics with rate constants k = 8.56×10−2 min-1 and 9.94x10-2 min-1 for iron and vanadium substituted - HPAs, respectively. Voir les détails

Mots clés : Wells-Dawson HPA, Homogeneous catalysis, Phenol photodegradation, UV irradiation

Pillared clays as catalysts for methyl parathion removal by advanced oxidation processes

Salim Kouraichi Mohamed El-Hadi Samar, Mostefa ABBESSI, Hassane BOUDOUH, Adel BALASKA  (2015)
Publication

A natural bentonite from Mostaganem in Algeria was modified by intercalation with polyoxocationic solutions (Al•Fe, Al•Co, Al•Cu, Al•Fe•Cu or Al•Fe•La). The modification of the bentonite occurred via pillaring by ionic exchange with these solutions. The addition of these solutions led to the formation of pillared clays with important catalytic properties in environmental impact reactions. The structural and textural properties of materials calcined at 500 °C were determined by several techniques: X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and N2 adsorption–desorption analysis. The pillared clays were then used as a Fenton-type heterogeneous catalyst for the heterogeneous sono-Fenton process for the oxidation of methyl parathion in water. The catalytic tests revealed the activity of the introduced iron species and the promoter effect of lanthanide or copper on the catalytic activity of these species. The sono-Fenton method showed promising results for the degradation of methyl parathion when compared with the Fenton method. Therefore, the sono-Fenton method can be a viable alternative technology to the existing methods for treating methyl parathion in wastewater. Voir les détails

Mots clés : Advanced oxidatio process, Sono-Fenton, heterogeneous catalysis, Methyl parathion pesticide, Wastewater treatment

Elimination du plomb en solution par la sciure de bois

Toufik CHOUCHANE, Saliha Chouchane, Atman Boukarai, Adel BALASKA, Mohamed Elhadi Samar  (2011)
Publication

Cette étude présente les résultats obtenus lors de l’utilisation de la sciure debois pour l’élimination du plomb contenu dans les eaux usées. Les propriétés de sorptionont été déterminées en régime discontinu. Les résultats des essais montrent qu’un grammede sciure de bois activé peut fixer 40,04 mg/g de plomb selon le modèle de Langmuir, 1erversion, avec une cinétique du pseudo premier ordre, où le temps d’équilibre est de 10minutes. Les mesures réalisées révèlent aussi, que la diffusion externe contrôle la vitessedu processus globale de la sorption. La diffusion dans les pores ne présente pas l’uniquemécanisme réactionnel limitant cette cinétique, ce mécanisme est basé aussi sur l’échangecationique, où les ions de bases jouent un rôle très important. En dernier, on montre quecette sorption est spontanée (ΔG < 0) jusqu'à 40 °C, exothermique (ΔH < 0) et aucunchangement n’a été effectué au niveau de la structure de la sciure de bois (ΔS < 0). Voir les détails

Mots clés : Plomb Sportion, Sciure de bois, eau, pollution

Synthesis, characterization of cesium and cobalt substitutedwells–Dawson heteropolyoxotungstates salts and their photocatalytic applications

Adel Balaska Robila Belghiche, Mohamed Elhadi Samar, Toufik CHOUCHANE, Roland Haseneder  (2013)
Publication

Heteropoly compounds in the solid state are ionic crystals (sometimes amorphous) consisting of large polyanions, cations, water of crystallization, and other molecules. Heteropolyacids (HPAs) have several advantages as catalysts. On the one hand, they have a very strong Brønsted acidity, especially the cobalt and cesium salts; on the other hand they are exhibiting fast reversible multielectron redox transformations under mild conditions. The cobalt and cesium salts of wells–Dawson HPAs were synthesized and characterized using elemental analysis and spectroscopic techniques (31P-NMR, FT-IR).The wells–Dawson anions possess the ability to accept or release electrons through an xternal potential or upon exposure to UV radiation (photochemical reactions). The catalytic tests of these salts were investigated on phenol degradation where the UV photodegradation of acidified aqueous solutions (pH = 2) were studied in a batch photoreactor under ambient temperature and continuous circulation of phenol solution. The results reveal high catalytic activity for two HPAs, the best catalyst is the salt of cesium; where the presence of cesium improves significantly both the photcatalytic activity and the selectivity to oxalic acid. Voir les détails

Mots clés : Characterisation Heteropolyacids Dawson- Type, Cesium, Cobalt Photo Catalysis

CARACTÉRISATION ET TRAITEMENT PARCOAGULATION-FLOCULATION D’UN EFFLUENT DE LAITERIE

Riad Ayeche, Adel BALASKA  (2010)
Publication

L’objectif de cette étude est de clarifier les eaux usées de la laiterie "EDOUGH" parun traitement physico-chimique en procédant à une coagulation-floculation douce ; à l’aide dedeux coagulants communément utilisés dans le traitement des eaux. Dans ce cas ; le sulfated’aluminium Al2(SO4)3 et la chaux Ca(OH)2 ont été testé en présence d’un floculant PE14.Les essais de traitement ont montré que les deux coagulants utilisés permettraient deréduire : les matières en suspension (MES), la charge organique, les éléments azotée etphosphorée. Le meilleur résultat a été enregistré par la chaux avec un abattement de 92 % desMES et 83 % de Pt (phosphate totale), ce qui garantit le respect des normes algérienne envigueur pour ces deux paramètres. Voir les détails

Mots clés : coagulation-floculation, Effluent laitier, Matière organique, Eau usée, pollution