Génie Chimique
Elaboration et caractÈrisation de nano revÍtements par voie chimique appliquÈs ‡ la protection des matÈriaux mÈtalliques
Dans ce travail, une Èlaboration de revÍtement par conversion chimique appliquÈ ‡ la protectiond’alliage AZ91 contre la corrosion a été réalisée en utilisant un bain de phosphatation dopé avec de nitrate de Bariumet d’oxyde de chrome. Les dépôts obtenus ont été caractérisé par AFM, DRX L’étude de l’efficacité de nos dépôts a été effectuée par la méthode de Tafel et la spectroscopie d’impédance électrochimique dans un milieu 3.5% NaCl.Les rÈsultats obtenus montrent qu’on a pu obtenir des dépôts de Zn-Ca-P, Zn-CaBa-P,Zn-Ca-Ba-P-Cr, ces derniers prÈsentent une efficacitÈ remarquable en termes de protection contre la corrosion dans le milieu ÈtudiÈ. Mots clÈ : corrosion, revÍtement, conversion chimique, phosphatation. ABSTRACT In this work, a chemical conversion coating was developed and applied for the protection of AZ91 alloy against corrosion. A phosphating bath doped with barium nitrate and chromium oxide was used. The obtained deposits were characterized by AFM and XRD. The effectiveness of our deposits was evaluated using the Tafel method and electrochemical impedance spectroscopy in a 3.5% NaCl solution. The results obtained demonstrate that we were able to obtain Zn-Ca-P, Zn-Ca-Ba-P, and Zn-Ca-Ba-PCr deposits. The latter showed remarkable efficiency in terms of corrosion protection in the studiedenvironment. Voir les détails
Mots clés : corrosion, coating, chemical conversion, phosphating.
Elaboration et caractérisation des nanoparticules Ferrite/ Mg/Mn par co-précipitation
Nanosciences and nanotechnologies have experienced great growth over the past fifteen years, thanks to the development of new tools for elaboration, observation and analysis. This thesis focuses on the development of iron-based nanoparticles by the coprecipitation method with an experimental protocol and under different temperature and pH conditions. The characterization of the phases was carried out by X-ray diffraction, Infrared spectroscopy with Fourier Transform FTIR and Ultraviolet-visible spectroscopy. Voir les détails
Mots clés : Nanosciences and nanotechnologies, iron-based nanoparticles, X-ray diffraction
Elaboration et caractérisation et applications des nanoparticules Bi-M par la méthode de Co-précipitation
Research around nanoparticles (NPs) is very popular in the scientific community. This thesis consists in developing bismuth iron (BiO) nanoparticles by the Co-precipitation method, under an experimental protocol and under different temperature and PH conditions , then these nanoparticles were characterized by different analysis techniques: FTIR infrared spectroscopy, X-ray diffraction (XRD), and UV-Vis spectroscopy; then to use the nanoparticles for the application to the adsorption of the dye (Methylene blue, Naphthol blueblack, bromophenol blue and posceau s extra). Voir les détails
Mots clés : X-ray diffraction (XRD), and UV-Vis spectroscopy;, UV-Vis spectroscopy, FTIR infrared spectroscopy
Études expérimentales et théoriques de l’extrait de Spergularia Rubra(Sabline rouge) en tant qu’un inhibiteur vert de corrosion de l’acier aucarbone X70 dans HCl 1M
The use of inhibitors is one of the most effective methods for protecting metals against corrosion.Nowadays, the development of non-toxic and biodegradable corrosion inhibitors is essential. Plantextracts have become important as an environmentally acceptable, readily available and usable sourceof inhibition for a wide range of corrosion prevention.The objective of this work is to study the inhibiting action of a plant substance ̎Spergularia Rubra̎ ,on the corrosion behavior of X 70 carbon steel widely used in the construction of pipelines, in 1M HCl,using different electrochemical techniques, namely impedance spectroscopy and Tafel method. Voir les détails
Mots clés : acid corrosion, steel, inhibition, green inhibitor, Spergularia rubra
Elaboration et caractérisation des nanoparticules ferrites de cobalt et leur application comme catalyseur pour l’élimination des colorants
Les ferrites de cobalt CoFe2O4 sont des nanoparticules magnétiques qui possèdent des propriétés importantes pour l’élimination des colorants .Ce travail est consacré à étudier l’influence de certains paramètres sur l’élaboration de CoFe2O4 et l’efficacité de ce dernier sur la dégradation des colorants . Les nanoparticules CoFe2O4sont élaborées à partir des cations de fer (Fe3+) et du cobalt (Co2 )par la méthode de la coprécipitation et autocombution,.Les caractéristiques de ces nanoparticules sont identifiés et comparées à l’aide de différentes techniques telles que la diffraction des rayons X (DRX) , la spectroscopie infrarouge à transformée de fourrier (FTIR) et la spectroscopie UV . Voir les détails
Mots clés : méthode de la coprécipitation et autocombution, Les ferrites de cobalt
Elaboration et caractérisation des nanoparticules a base de chlorure d’étain SnCl2 et l’application d’élimination de colorants par adsorption
Nanoparticles (NPs) have received considerable attention in recent years due to their unique physicochemical and optoelectronic properties and their applications in various sectors of chemistry, environment, medicine, agriculture and electronics. This dissertation will focus on three main parts, after an introduction to nanotechnologies: a bibliographic study on everything related to nanoparticles, their types, their synthesis methods, their characterizations, their properties and their applications. In the second part we have cited all the experiments of elaboration of our samples of nanoparticles (based on tin chloride) using the method of Co-precipitation so that at the end we have chosen the one that gives the best result to use it in the application of removal of methyl blue dye by adsorption. The third part shows that the results of our samples are excellent and from there we concluded that the nanoparticles (tin ferrites) and thanks to their magnetic behavior they allow to eliminate easily the methyl blue dye by magnetic field. Voir les détails
Mots clés : Nanoparticles (NPs), Magnetic field
Développement d’un Biomatériau à Base de Polymère etRenfort Végétale
In the last few years, there has been a strong interest in the development of biodegradablepolymers as an alternative for many applications. This is in order to reduce the largeconsumption of plastic causing environmental problems.In this study we develop low cost and low density biodegradable composite materials thatcan be recycled and help to combat the pollution problems of the 21st century. The workdone in this thesis is oriented along this axis and aims to develop mixtures based on polyvinylchloride and fiber Atriplex halimus whose loading rates vary from 1% to 10%. The varioustechniques of characterization were carried out on the developed mixtures. The physicalproperties such as absorption, as well as mechanical, hardness, tensile test, showed animprovement of the content and resistance of our material reinforced by the vegetable fiber.These observations lead us to conclude that such a material can be used on an industrialscale for packaging applications Voir les détails
Mots clés : composite materials, Polyvinyl chloride, Atriplex halimus, Vegetable fiber
ELABORATION PAR SYNTHÈSE VERTE ET CARACTÉRISATION DES NANOPARTICULES D'OXYDES DE FER ET LEUR APPLICATION ÀL'ADSORPTION DU COLORANT BLEU DE MÉTHYLÈNE
Nanosciences and nanotechnology are the technological and scientific revolution of today, as was microtechnology in 1970-1980. The objective of green synthesis is to minimize, at best, the danger and considerably increase the efficiency of certain chemical practices, particularly at the nano-scale.This work consists first of all in synthesizing iron oxide nanoparticles by the "Green Synthesis" method based on plant extracts and metal salts; then to characterize the nanoparticles produced by different analysis techniques: Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) associated to Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) ); then to use the nanoparticles for the application to the adsorption of the dye (methylene blue). Voir les détails
Mots clés : Nanosciences, Nanotechnology, Microtechnology, X-ray diffraction, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy
Etude du pouvoir inhibiteur de l’extrait de la Spergularia ruba(sabline rouge) vis-à-vis de la corrosion de l’acier X70 dans une solution acide HCl 1M
Some organic compounds are considered as effective inhibitors for the corrosion of steels in the acid medium, when they are added in low concentrations; they can reduce or stop the corrosion of the exposed metal. Their operating principle is based on the protection of the metal of its environment. In this work we were interested in the study of the effect of the Spergularia ruba extract on the corrosion of X70 steel in a molar solution of hydrochloric acid at 25 ° C. Inhibitory efficiency and mode of action were evaluated by both gravimetric and electrochemical methods. The results obtained showed that the efficiency exceeds 82% for a maximum concentration of 560 mg / L, and increases with immersion time at room temperature. Voir les détails
Mots clés : acid corrosion, steel, inhibition, green inhibitor, Spergularia ruba
Elaboration des nanoparticules métalliques par co-précipitation et caractérisation structurale
Nanoparticles are now part of everyday life; researchers have developed new tools with their structural and magnetic properties interesting for various fields ranging from health as well as the environment. The objective of this study is the elaboration of metallic nanoparticles in order to optimize the working conditions and the properties of these nanoparticles, and the structural and magnetic characterization. We used a weakest and least expensive synthesis method that co-precipitates. We found that pH value, working temperature, and precursor nature influence particle size, morphology, chemical composition, and magnetic behavior. We have shown that increasing pH, temperature, and sulfide-type precursor utilization decreased the size of nanoparticles and led to improved properties such as chemical composition, morphology, and saturation magnetization. Voir les détails
Mots clés : metallic nanoparticles