Étude comparative de l’électrocoagulation et de la coagulation floculation vis-à-vis de la déstabilisation d’une émulsion d’huile de coupe

Ce travail a porté sur la déstabilisation d’une émulsion d’huile de coupe algérienne (Tasfalout 22/B) par électrocoagulation (EC) en batch en utilisant des électrodes de fer. L’efficacité du procédé est évaluée par la mesure de la turbidité. Une meilleure efficacité de déstabilisation est obtenue par une augmentation de la densité de courant de 50 à 350 A•m‑2 pour un temps d’électrolyse de 15 min et des concentrations en huile de coupe de 1 % (p/p), 2 % (p/p) et 4 %(p/p). Un rendement d’élimination en turbidité de 99 % a été obtenu pour une émulsion à 4 % (p/p), une densité de courant de 150 A•m‑2 et un temps d’électrolyse de 120 min.Le suivi de la cinétique de dissolution de l’électrode de fer sur une période de 120 minutes a montré qu’une même efficacité du procédé peut être obtenue par une diminution du temps d’électrolyse et une augmentation de la densité de courant.Une étude comparative des performances de l’électrocoagulation et de la coagulation-floculation au chlorure ferrique hydraté (FeCl3•6H2O), vis-à-vis de la déstabilisation d’une émulsion d’huile de coupe, a été réalisée. Elle a mis en évidence l’avantage de la coagulation-floculation pour l’émulsion à 1 % (p/p), pour les différentes densités de courant testées en électrocoagulation. Par contre, les rendements d’élimination pour les deux procédés sont sensiblement similaires pour les émulsions plus concentrées (2 % (p/p) et 4 % (p/p)), pour une densité de courant de 150 A•m‑2. Le pH des émulsions obtenu par les deux procédés après le traitement est différent. Le milieu reste alcalin dans l’électrocoagulation et il devient acide dans la coagulation floculation.This work focuses on the breakdown of an Algerian cutting oil emulsion (Tasfalout 22/B) by batch electrocoagulation (EC) using iron electrodes. The efficiency of the process was estimated from turbidity measurements. An improved efficiency of destabilization was obtained by increasing the current density from 50 to 350 A•m‑2, over an electrolysis time of 15 min and using cutting oil concentrations of 1% (w/w), 2% (w/w) and 4% (w/w). Monitoring of the kinetics of the electrode dissolution over a period of 120 min showed that a similar process efficiency was obtained by decreasing the electrolysis time and by increasing the current density. A 99% removal of turbidity was obtained for an emulsion of 4% (w/w) with a current density of 150 A•m‑2 and an electrolysis time of 120 min.A comparison of the performances of electrocoagulation and of coagulation-flocculation with hydrated ferric chloride (FeCl3•6H2O) processes was carried out, with respect to the destabilization of cutting oil emulsion. This comparison highlighted the advantage of the coagulation-flocculation process for the of 1% (w/w) emulsion at different electrocoagulation current densities. However, for a current density of 150 A•m‑2, the removal efficiency of both processes was similar for the emulsion with higher cutting oil concentrations (2% (w/w) and 4% (w/w)). The pH of the emulsion obtained by the two processes following treatment varied. The medium remained alkaline during the electrocoagulation process and became acidic during the coagulation-flocculation process

Etude des potentialités de nouveaux procédés de traitement d'émulsions hydrocarbure-eau (ultrafiltration, distillation et couplage coalesceur-hydrocyclone)

TOULOUSE-INSA (315552106) / SudocSudocFranceF

Contribution à la mise au point d'application spécifique des hydrocyclones en traitement des eaux

Ce mémoire a permis d'explorer des potentialités originales des hydrocyclones dans le domaine général du traitement des eaux et a montré des possibilités intéressantes d'utilisation de ces séparateurs pour des applications spécifiques. La première application potentielle testée a été le traitement des eaux pluviales. On a montré l'intérêt d'utiliser dans ce cas un hydrocyclone spécifique équipé d'un microdécanteur placé au niveau de la sousverse appelé Grit pot qui permet de cumuler les avantages respectifs d'un hydrocyclone et d'un décanteur sans en présenter les inconvénients respectifs. La deuxième application était quant à elle relative aux potentialités de recyclage de talc utilisé comme agent lestant en traitement biologique et de charbon actif dans une filière de traitement des eaux potables. Dans les 2 applications, on a montré que l'hydrocyclone permet de recycler économiquement aussi bien le talc que le charbon actif. La dernière partie du mémoire, la plus innovante a permis de montrer la viabilité technique d'un procédé d'épuration des eaux hybride intégrant dans un même appareillage 3 procédés unitaires à savoir : coagulation-floculation, flottation à air dessous et séparation centrifuge.The aims of this research are to study the potential of using hydrocyclone in water treatment field and to study the possibility of applying hydrocyclone in some specifics applications. The first specific application is to use the hydrocyclone equipped, at the underflow outlet, with the microdecanter called Grit pot in run-off water treatment processes. This specific hydrocyclone had the advantages of the two processes, hydrocyclone and decanter without presenting their disadvantages. The second specific application concerns the potential of the recycle of talc, which was used as a ballasting additive in biological treatment, and activated carbon, which was used in potable water treatment. In these 2 applications, hydrocyclone showed its high performance and economically recycled of talc as well as activated carbon. The last part of this research, the most innovating part, is to study the technical feasibility of the hybrid process, which integrated in the same reactor with 3 processes: coagulation-flocculation, dissolved air flotation and centrifugal separation in water treatment field.TOULOUSE-INSA (315552106) / SudocSudocFranceF

CONTRIBUTION A L'ETUDE DU TRAITEMENT DES EAUX PAR CONGELATION (POTENTIALITES ET APPLICATIONS)

TOULOUSE-INSA (315552106) / SudocSudocFranceF

Contribution à la mise au point d'un logiciel de calcul de procédés et filières de traitement d'eaux residuaires huileuses

TOULOUSE-INSA (315552106) / SudocSudocFranceF

Chemomechanical transformations of gels

The needs for actuators with improved performances (in accuracy, speed of motion, power, response rate, compactness, compliance ...) in medical, spatial, marine areas have motivated the research on the study and the construction of new actuation systems having some characteristics of the human or animal muscle (natural muscle).The natural muscles are based on chemical to mechanical conversions (mechanoche- mical). These transformations can be obtained artificially by using chemomechanical materials : polymeric gels, ion exchange polymers, collagens and kitines. All these materials (natural or synthetic) consist of polymeric chains cross-linked in networks.The purpose of the work is the design of a muscle that has a similar structure derived from the original contractile pneumatic McKibben muscle. Some artificial muscles are conceived with chemomechanical power generation (by swelling and shrinking of materials inside the muscle) in the GARI Laboratory of DGE-INSAT. So these muscles with a contractile covering are rather similar to natural muscles due to their power supply and their covering.The first part of this paper gives a brief review of chemomechanical transformations of “soft gels” (hydrogels and organogels) and “hard gels” (ion exchange polymers). The soft gels are obtained either by an irreversible chemical reaction between preexisting linear chains (chain cross-linking) or by polymerisation of monomers, some of which having more than 2 reacting groups. They are able to retain a liquid in their tridimensional network. Factors (solvent, pH, temperature, electric field) provoking a modification of the network/liquid equilibrium can induce drastic volume changes. In the case of ion exchangers with weak basic groups, chemomechanic transformations result from an effect of the solvation in aqueous phase. For such polymers which have a granular morphology, addition of acidic or alkaline solutions provokes a swelling-deswelling cycle which can be controlled by the reaction stoechiometry.The second part is devoted to artificial muscles using these materials. At first, the ideal artificial muscle relative to the natural muscle performances is defined. Then, some chemomechanical muscle systems are presented including the robotic fish, worm-like muscle, gel fish, gel finger found in literature and our muscle constructed in the DGE-INSAT, in collaboration with GPI-INSAT and ENSIGC.The third part shows the chemomechanical actuators and the actuator function. Then the main characteristics of usual drive systems (electric, hydraulic and pneumatic actuators) are reviewed. The chemical actuator projects are presented : gel finger micro robot, gel motor, gel arm, robotic gripper abroad, our chemomechanical actuator using polymeric gels or ion exchange polymer in an adapted structure of the McKibben muscle type in Toulouse. The identification of the dynamic behavior (isotonic and isometric) has been achieved (using the MATLAB toolbox) for the ion exchange polymer muscle. This modelling is necessary for the computer control of the actuator using two chemomechanical muscles.It is now possible to consider how mechatronic actuation systems to drive a robot joint can be constructed, based on the performance range of the natural muscle : power/weight ratio, light, durability, flexibility, easy control in stabilisation and tracking of trajectory, low cost and low sensitivity to radiations

Chemomechanical transformations of gels: artificial muscles and chemomechanical actuators

Chemomechanical transformations are used to produce a mechanical force from a reversible chemical reaction for the purpose of generating artificial muscle contractility, on the model of biological muscle. We try to specify this notion of artificial muscle and to show how chemomechanical transformations can lead to such devices. The design and experimentation of an original artificial muscle using ion exchange polymer or polymeric gel reacting inside a soft envelope, derived from research on pneumatic artificial McKibben muscle, is presented. The possibility of a chemomechanical actuator by setting in antagonism two artificial muscles is briefly analysed

Cover crop response to increased concentrations of copper in vineyard soils: Implications for copper phytoextraction

The use of cover crops (CCs) in viticulture is threatened by the contamination of vineyard soils by copper (Cu). This study investigated the response of CCs to increased concentrations of Cu in soil as a way to assess their sensitivity to Cu and their Cu phytoextraction ability. Our first experiment used microplots to compare the effect of increasing soil Cu content from 90 to 204 mg kg(-1) on the growth, Cu accumulation level, and elemental profile of six CC species (Brassicaceae, Fabaceae and Poaceae) commonly sown in vineyard inter-row. The second experiment quantified the amount of Cu exported by a mixture of CCs in vineyards with contrasted soil characteristics. Experiment 1 showed that increasing the soil Cu content from 90 to 204 mg kg(-1) was detrimental to the growth of Brassicaceae and faba bean. The elemental composition of plant tissues was specific to each CC and almost no change in composition resulted from the increase in soil Cu content. Crimson clover was the most promising CC for Cu phytoextraction as it produced the most aboveground biomass, and, along with faba bean, accumulated the highest concentration of Cu in its shoots. Experiment 2 showed that the amount of Cu extracted by CCs depended on the availability of Cu in the topsoil and CC growth in the vineyard, and ranged from 25 to 166 g per hectare. Taken together, these results emphasize the fact that the use of CCs in vineyards may jeopardised by the contamination of soils by Cu, and that the amount of Cu exported by CCs is not sufficiently high to offset the amount of Cu supplied by Cu-based fungicides. Recommendations are provided for maximizing the environmental benefits provided by CCs in Cu-contaminated vineyard soils

Developpement d'un procede de traitement des slops de raffineries avec valorisation des hydrocarbures recuperes

Available from INIST (FR), Document Supply Service, under shelf-number : RP 400 (2364) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc