Thèses sur le sujet « Emulsion extraction »

The goal of this research is to improve an extractive metallurgy process based

on solvent extraction. This process should fit the exploitation of small local

copper-rich deposits. In these conditions, the plant has to be as compact as

possible in order to be easily transported from one location to a subsequent

one. Improved extraction kinetics could ensure a high throughput of the

plant despite its compactness. In addition, the extraction reagent should

not be damaging for the environnement. On this basis, we propose to use

ultrasound-assisted solvent extraction. The main idea is to increase the

extraction kinetics by forming an emulsion in place of a dispersion thanks to

the intense cavitation produced by ultrasound. The benefit of this method

is to improve the copper extraction kinetics by increasing the interfacial

surface area and decreasing the width of the diffusion layer. We studied the

implementation of an highly branched decanoic acid (known as Versatic-

10®acid) as a copper extraction reagent dispersed in kerosene.

Emulsification is monitored through the Sauter diameter of the organic

phase droplets in aqueous phase. This diameter is measured during pulsed

and continuous ultrasound irradiation via a static light scattering technique.

The phenomenon of emulsification of our system by ultrasound is effective,

and the emulsification process carried out in the pulsed ultrasound mode is

at least as efficient as the emulsification obtained under continuous mode.

No improvement of emulsification is observed beyond a threshold time of

the ultrasound impulse. This may be attributed to a competition between

disruption and coalescence. The use of mechanical stirring combined with

pulsed ultrasound allows to control the droplet size distribution.

In presence of ultrasound, the extraction kinetics of Versatic-10 acid is

multiplied by a factor ten, and therefore reached a value similar to the kinetics

observed without ultrasound with an industrial extractant such as

LIX-860I®(Cognis). Extraction kinetics measurements are carried out by

monitoring the copper ion concentration in the aqueous phase with an electrochemical

cell.

We conclude that ultrasound-assisted emulsification can be implemented

under certain conditions. Emulsification is a first step, and the following

destabilization step has to be studied. The device using ultrasound-assisted

emulsification should be followed by an efficient settling-coalescing device. A

possible solution would be to promote emulsion destabilization by increasing

the ionic strength with an addition of MgSO4, a salt that is not extracted

by the extraction reagent in the considered range of pH.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

Nano-assisted inclusion separation of alkali metals from basic solutions was reported by inclusionfacilitated emulsion liquid membrane process. The novelty of this study is application of nano-baskets of calixcrown in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this aim, four derivatives of diacid calix[4]-1,3-crowns-4,5 were synthesized, and their inclusionextraction parameters were optimized including the calixcrown scaffold (4, 4 wt%) as the carrier/ demulsifier, the commercial kerosene as diluent in membrane, sulphonic acid (0.2 M) and ammonium carbonate (0.4 M) as the strip and the feed phases, the phase and the treat ratios of 0.8 and 0.3, mixing speed (300 rpm), and initial solute concentration (100 mg/L). The results reveled that under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98-99%. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35137

En réponse aux attentes actuelles des consommateurs pour des produits de haute qualité nutritionnelle et environnementale, et face aux impératifs industriels conduisant à minimiser les risques et l’impact environnemental lors de l’extraction à l'hexane de l’huile de la graine de colza, l’étude de l’extraction aqueuse avec assistance enzymatique de cette huile a été reprise avec 2 objectifs principaux : déterminer les enzymes et mélanges d'enzymes adaptés à la meilleure déstructuration du tissu adipeux végétal, et d'autre part étudier les propriétés et la déstabilisation de l'émulsion formée. De l'optimisation de ces 2 séquences du process dépendent les rendements finaux en huile de l'extraction et les propriétés du tourteau, qui constituent les clés économiques de l'émergence de cette nouvelle technologie. Pour cela, après caractérisation physicochimique des constituants de la graine, protéases et polysaccharides hydrolases ont été testées seules ou en combinaison afin d’optimiser le rendement en huile libre et en huile contenue dans l’émulsion engendrée lors de l’extraction et obtenue par centrifugation. Après caractérisation de l’émulsion (rhéologie, diffusion statique de la lumière, pH, conductivité), des tests de déstabilisation physicochimiques ou thermo-mécaniques ont été mis en œuvre afin de séparer les constituants de l’émulsion formée, et obtenir ainsi la libération de l'huile. Les tests réalisés ont permis de retenir trois procédés de déstabilisation: l’addition de talcs, l’inversion de phase par addition d’huile exogène en présence de NaCl dans la phase aqueuse, et les cycles de congélation/décongélation. Afin d’apporter les premiers éléments de l’optimisation de ce dernier procédé, une étude par planification expérimentale a été mise en œuvre
Consumer's concerns about the quality and environmental impact of the products as well as the industrial requirements regarding the risk assessment and the environmental and health repercussions of the solvent extraction of rapeseed oil using hexane led us to work on the optimisation of the aqueous enzymatic extraction of this oil. The study has been carried out to determine the best combination of enzymes able to achieve the disruption of the vegetal adipose tissue, and to characterize the emulsion obtained after centrifugation. The final objective was to maximize the yields of the oil extraction and to obtain adequate nutritional properties of the cake. After the physicochemical characterization of the rapeseed raw material, several proteases and polysaccharide hydrolases have been tested individually and in combination in order to optimize the removal of free oil and the emulsion oil yield occurring during the aqueous extraction process. The physicochemical properties of the emulsion have been determined: rheological properties, pH, conductivity, spectroscopy by Short Angles Light Scattering). Thereafter some physicochemical and thermo-mechanical treatments have been carried out to destabilize the oil-in-water emulsion obtained after the centrifugation, which contained a large part of the total oil of the reaction mixture. Three destabilization processes appeared particularly interesting to increase the free oil removal from the emulsion: talc addition before centrifugation, phase inversion by addition of exogenous oil in presence of NaCl in the aqueous phase, and freezing/thawing cycles. Finally, an optimisation trial of the freezing/thawing process using a Doehlert experimental design has been done as an example

2010 - 2011
Controlled release systems for therapeutic drugs have received extensive attention in recent years, due to their great clinical potential. Biodegradable microspheres are well-recognized systems to control the release rate of a drug out of a pharmaceutical dosage form; they are able to protect these agents against rapid degradation and clearance and release them in the body with a desired controlled rate and amount. Particularly, biopolymer microspheres are attracting increasing attention as drug carriers for injectable controlled release formulations. Biopolymer microspheres for controlled drug delivery can be conventionally prepared by solvent evaporation/extraction of emulsions, but this technique shows many drawbacks (high temperature, long processing times, large polidispersity, high residual solvents, lower encapsulation efficiency). To overcome the limits of the traditional process, in recent years, Supercritical Emulsion Extraction (SEE) has been proposed for the production of drug/polymer microspheres with controlled size and distribution, starting from oil-in-water (o-w) and water-in-oil-in-water (w-o-w) emulsions. This process uses supercritical carbon dioxide (SC-CO2) to extract the “oil” phase of emulsions, leading to near solvent-free microparticles. SEE offers the advantage of being a one-step process and is superior to other conventional techniques for the better particle size control, higher product purity and shorter processing times; but, as traditional processes, it shows problems related to batch-to-batch reproducibility and reduction of the process yield, due to the intrinsically discontinuous operation. In the present work, a novel SEE configuration is proposed in a continuous operation layout (Continuous Supercritical Emulsion Extraction, SEE-C) using a countercurrent packed tower, for the production of controlled-size biopolymer microparticles in a robust and reproducible mode. Particularly, the purpose of this thesis is the optimization and characterization of the SEE-C process to investigate its capabilities and performances in the production of poly-lactic-co-glycolic acid (PLGA) microparticles with an engineered size and distribution and charged with different active principles (APs). Before to investigate the possibility to produce AP/PLGA microspheres, an optimization of the process has been performed. Indeed, the thermodynamics of the selected system (ethyl acetate+CO2) has been studied, together with the analysis of the process operating parameters. Moreover, a fluidodynamic characterization of the packed tower has been carried out to identify the best condition of operation, below the flooding point. The capacity limits for the packing material have been evaluated and, then, directly measured in terms of flooding point at different operating conditions. Afterwards, firstly blank (drug-free) PLGA microparticles have been successfully produced, starting from single and double emulsions. Secondly, anti-inflammatory drugs (such as Piroxicam and Diclofenac Sodium), corticosteroids (such as Hydrocortisone acetate) and proteins (such as Insulin) have been chosen as model compounds to be entrapped within PLGA microspheres. All the emulsions produced were stable with non-coalescing droplets. The corresponding microspheres obtained were spherical in shape and well-defined with narrow size distributions, due to the short processing time that prevents aggregation phenomena typically occurring during conventional solvent evaporation process. The influence of some emulsion formulation parameters (such as polymer concentration and emulsion stirring rate) on particle size has been investigated, showing that the droplet formation step determines size and size distribution of the resulting microspheres; particularly, a significant increase in particle size with the increase of polymer concentration or the decrease of emulsion stirring rate has been observed. Moreover, the effect of kind and formulation of emulsion on the microsphere characteristics has also been investigated, demonstrating that the choice of the encapsulation approach and the emulsion composition have a considerable influence on the attainable drug encapsulation efficiency. The produced microspheres have been characterized by X-ray, DSC, HPLC and UV-vis analysis. DSC and X-ray analyses confirmed that the microspheres were formed by an AP/PLGA solid solution and the active principle was entrapped in an amorphous state into the polymeric matrix. HPLC analysis revealed that good encapsulation efficiencies have been obtained in the products obtained. Release studies showed uniform drug concentration profiles, confirming a good dispersion of the drug into the polymer particles. The obtained AP/PLGA microspheres can degrade and release the encapsulated active principle slowly with a specific release profile. Active principle loading, particle size and emulsion kind revealed to be the controlling parameters for drug release. A study of PLGA microparticles degradation has also been carried out to monitor any morphological difference in time of the biodegradable devices produced by SEE-C. Moreover, a comparative study between the characteristics of the PLGA microspheres obtained by SEE-C and the ones produced by the corresponding batch operating mode process (SEE) and conventional evaporation technology (SE) has been performed. PLGA microparticles produced by SEE-C showed a mean particle size always smaller than that associated with particles produced by SEE and SE; physico-chemical properties showed no morphological and structural differences between the processes. Compared with conventional technologies for the preparation of drug delivery systems, e.g. solvent evaporation emulsion techniques, the novel process is environmentally superior and suitable for scaling up to industrial dimensions. Moreover, the higher degree of control, as indicated by the high reproducibility, makes validation of the process very simple. In conclusion, the SEE-C process has shown to be an attractive way of incorporating active principles into biodegradable microparticles for controlled release formulations. Greater product uniformity, higher throughput with smaller plant volumes and elimination of batch-to-batch repeatability problems are the significant advantages observed. [edited by author]
X n.s.

Ce doctorat a pour de comparer deux procédés d'extraction de biomolécules, comme l'acide gallique. Le phosphate de tributyle (TBP), dilué dans le dodécane, est choisi comme extractant et Na2HPO4 comme désextractant pour leur efficacité. Avec ces réactifs, nous avons déterminé le mécanisme des deux systèmes extractifs. L'extraction liquide-liquide est limitée par l'équilibre thermodynamique : elle est efficace pour des concentrations élevées de TBP. Quant à l'extraction par émulsion, elle ne l'est pas ; si l'émulsion est stable, l'extraction peut être rapide et totale avec des concentrations de TBP plus faibles, ce qui rend ce procédé plus vert que le précédent. La dernière partie de l'étude porte sur le remplacement du dodécane par des agrodiluants afin d'obtenir des procédés encore plus verts. L'utilisation d'esters éthyliques d'acide gras permet d'augmenter l'extraction en présence de TBP et même d'éviter son emploi en extraction par émulsion.

Third phase formation is an undesirable phenomenon during the PUREX process, which is a continuous liquid-liquid extraction approach for the reprocessing of uranium and plutonium from spent nuclear fuel. When third phase formation occurs, the organic extraction solution splits into two layers. The light upper layer, which is commonly named the light organic phase, contains a lower concentration of metal ions, tri-n-butyl phosphate (TBP) and nitric acids but is rich in the organic diluent. The heavy lower layer, which is commonly named the third phase, contains high concentrations of metal ions, TBP and nitric acids. As the third phase contains high concentrations of the uranium and plutonium complexes it can thus cause processing and safety concerns. Therefore, a comprehensive understanding of the mechanism of third phase formation is needed so as to improve the PUREX flowsheet. To investigate third phase formation through molecular simulations, one should first obtain reliable molecular models. A refined model for TBP, which uses a new set of partial charges generated from our density functional theory calculations, was proposed in this study. To compare its performance with other available TBP models, molecular dynamics simulations were conducted to calculate the thermodynamic properties, transport properties and the microscopic structures of liquid TBP, TBP/water mixtures and TBP/n-alkane mixtures. To our knowledge, it is only TBP model that has been validated to show a good prediction of the microscopic structure of systems that consist of both hydrophobic and hydrophilic species. This thesis also presents evidence that the light-organic/third phase transition in the TBP/n-dodecane/HNO3/H2O systems, which is relevant to the PUREX process, is an unusual transition between two isotropic, bi-continuous micro-emulsion phases. The light-organic /third phase coexistence was first observed using Gibbs Ensemble Monte Carlo (GEMC) simulations and then validated through Gibbs free energy calculations. Snapshots from the simulations as well as the cluster analysis of the light organic and third phases reveal structures akin to bi-continuous micro-emulsion phases, where the polar species reside within a mesh whose surface consists of amphiphilic TBP molecules. The non-polar n-dodecane molecules are outside this mesh. The large-scale structural differences between the two phases lie solely in the dimensions of the mesh. To our knowledge, the observation of the light-organic/third phase coexistence through simulation approaches and a phase transition of this nature have not previously been reported. Finally, this thesis presents evidence that the microscopic structure of the light organic phase of the Zr(IV)/TBP/n-octane/HNO3/H2O system, which is also related to the PUREX process, is different from that of the common hypothesis, where such system is consisted of large ellipsoidal reverse micelles. Snapshots from simulations, hydrogen bonding analysis and cluster analysis showed that the Zr4+, nitrate, TBP and H2O form extended aggregated networks. Thus, as above, we observe a bi-continuous structure but this time with embedded local clusters centred around the Zr4+ ions. The local clusters were found to consist primarily of Zr(NO3)4·3TBP complexes. This finding provides a new view of the structure of the Zr(IV)/TBP/n-octane/HNO3/H2O system.

Extraction processes employing emulsion liquid membranes (ELMs), water-in-oil emulsions dispersed in aqueous phase, have been shown to be highly efficient in removing a variety of organic and inorganic contaminants from industrial wastewaters. As a result, they have been considered as alternative technologies to other more common separation processes such as pressure-driven membrane processes. Unfortunately, a widespread use of the ELM process has been limited due to the instability of emulsion globules against fluid shear. Breakup of emulsions and subsequent release of the internal receptor phase to the external donor phase would nullify the extraction process. Numerous studies have been, therefore, made in the past to enhance the stability of ELMs. Examples include adding more surfactants into the membrane phase and increasing the membrane viscosity. However, increased stability has been unfortunately accompanied by loss in extraction efficiency and rate in most reported attempts. The primary objective of this research is to apply the ELMs in a unique contacting device, a Taylor-Couette column, which provides a relatively low and uniform fluid shear that helps maintaining the stability of emulsion without compromising the extraction efficiency of a target compound. The ELM used in this study is made of membrane phase converted into non-Newtonian fluid by polymer addition, which provides additional uncommon remedy for the problem. This innovative ELM process was optimized to treat various types of simulated industrial wastewaters containing selected phenolic compounds and heavy metals. Experiments performed in this study suggested that the newly developed ELM process achieved exceptionally high overall removal efficiencies for the removal of these target compounds in relatively short contact time. Mechanistic predictive models were further developed and verified with the experimental data. Combined with the experimental data and novel mathematical predictive models, this study is expected to have a high impact on immediate practices of emulsion liquid membrane technologies in relevant industries.

Le concept de bioraffinerie désigne le procédé de transformation de la biomasse en divers produits commercialisables et en énergie, l’accumulation d’agro-résidus étant ainsi significativement réduite. Ce travail propose un processus de bioraffinerie du germe de maïs et du tourteau de pressage de noix. Pour le germe de maïs, le procédé comporte une première étape d’extraction d’huile pour laquelle différentes méthodes ont été mises en œuvre, suivie de l’extraction des protéines et de l’évaluation du potentiel stabilisant des résidus solides (émulsions de Pickering). Il a été montré que la méthode d’extraction d’huile influençait les fonctionnalités (solubilité, capacité d’absorption d’eau, propriétés moussantes et émulsifiantes) des protéines et que les farines de germe de maïs étaient des agents stabilisants d’émulsions huile dans eau (H/E) performants. Pour le tourteau de noix, source d’huile et de composés phénoliques antioxydants, le travail s’est focalisé sur l’extraction assistée par ultrasons de composés phénoliques du tourteau deshuilé et l’évaluation des capacités émulsifiantes des résidus solides. Les extraits ont montré une forte capacité à piéger les radicaux libres et les résidus solides ont permis de fabriquer des émulsions H/E fines très stables. L’extraction assistée par ultrasons a également été appliquée à l’extraction des composés phénoliques d’un troisième co-produit, le marc de raisin. Les paramètres statistiquement influents ont été identifiés pour les deux matrices
The concept of biorefinery has emerged as an industrial facility where biomass is transformed into a wide range of marketable products and energy, and the accumulation of agro-residues is significantly reduced. This work proposed a biorefinery scheme from corn germ and walnut press-cake as by-products. For corn germ, the scheme involved a first step of oil recovery by different methods followed by protein extraction while solid residues were assessed for stabilizing emulsions (Pickering emulsions). It was demonstrated that protein functionalities (such as solubility, water absorption, foaming and emulsifying capacities) were influenced by oil extraction method, and that corn germ meals showed high capacity to stabilize oil-in-water emulsions. For walnut press-cake, a source of oil and phenolic antioxidants, the scheme focused on ultrasound assisted extraction of phenolics from the defatted cake, and the stabilizing ability of the residue particles. Extracts exhibited a high capacity of scavenging free radicals (DPPH) and walnut cake particles allowed to fabricate highly stable oil-in-water emulsions with fine droplets (1-2 µm). Ultrasound assisted extraction was also applied to recover phenolics from a third by-product that was a grape pomace. Influent parameters of extraction were statistically identified for both matrices with trends positively modeled by second-order polynomial equations

Le premier cycle d'extraction du procede de retraitement du combustible nucleaire irradie a pour fonction d'extraire, a partir du combustible dissous, l'uranium et le plutonium en phase organique ; et de laisser les produits de fission dans la phase aqueuse. Cette operation industrielle peut etre considerablement genee par la presence a l'interface d'une emulsion stable et envahissante, qui emprisonne des produits solides radioactifs. Ce phenomene est generalement nomme crasses d'interphase. Le travail que nous avons effectue vise a mieux comprendre l'origine et les mecanismes de formation de ce phenomene. Il a ete conduit a l'echelle du laboratoire, en simulant, en inactif, ses conditions d'apparition. Ainsi, nous avons pu verifier qu'un solide peut perturber un systeme biphasique jusqu'a stabiliser une emulsion. Ceci, en fonction de son affinite pour chacune des phases liquides, qui est tributaire de ses proprietes de surface. Differents produits solides peuvent etre presents au premier cycle. Ce sont, d'une part les produits de fission insolubles (provenant de la dissolution et non elimines par la clarification) ; et d'autre part, les precipites d'interphase (produits de fission solubles pouvant se combiner avec des produits de degradation du solvant pour donner des complexes insolubles). Nous avons confirme que l'apparition a l'interface de ces deux classes de produits etait consecutive a la degradation radiochimique du systeme biphasique. Leur comportement dans le systeme experimental a ete etudie. Apparemment, aucune des deux classes de produits n'est responsable a part entiere de la formation des crasses. C'est leur presence simultanee qui provoque l'apparition d'une emulsion stable. Ainsi, le phenomene de crasses d'interphase a pu etre reproduit, son origine et les mecanismes de formation precises. Enfin, l'analyse des resultats nous a permis de montrer qu'un tel probleme ne pouvait survenir dans le cadre d'un fonctionnement nominal du premier cycle d'extraction, et qu'il etait vraisemblablement le resultat de dysfonctionnement du procede.

Les pommes sont considérées comme bénéfiques pour la santé, de part leur teneur en polyphénols qui leur confèrent l’étiquette "d’aliment santé". Les procédés de transformation agroalimentaire des fruits et légumes génèrent des coproduits qui sont considérés comme sans valeur par les industriels. Or, au regard des volumes générés, ce sont des sources abondantes de nutriments.Une voie possible de valorisation de ces coproduits est la réintroduction dans des produits alimentaires en tant qu’ingrédient, de façon à proposer des aliments enrichis en molécules fonctionnelles. Pour ce faire, deux voies ont été explorées: l’utilisation de poudres d’épidermes de pommes pour stabiliser une émulsion et l’extraction des polyphénols au moyen de la technologie à base de CO2 supercritique. Ce travail examine également des solutions pour remédier au problème de brunissement enzymatique, comme le traitement thermique et l’addition de poudres de fruits naturellement riches en agents antibrunissement.Les phases de préparation des pommes sont de réelles étapes de transformation qu’il faut optimiser et maîtriser afin de préserver toutes les propriétés antioxydantes des coproduits végétaux. Nos travaux ont également permis de mettre en évidence des propriétés plus fonctionnelles des pelures de pommes, comme agent stabilisant d’émulsions. L’impact des paramètres d’extraction a été mis en évidence par l’exploration de plusieurs conditions telles que la masse chargée, le broyage, le protocole ainsi que la température et la composition du fluide extractant
Apples are considered beneficial to health, because of their content of phenolic compounds that confer the label "health food". Fruits and vegetables food processes generate byproducts that are considered worthless by industrial. However, given the volumes generated, they are rich sources of nutrients.One possible way of valorization of these byproducts is the reintroduction of food as ingredient, to propose fortified foods with functional molecules. To do this, two approaches have been explored: the use of apple peels powders to stabilize an emulsion and the extraction of phenolic compounds by supercritical CO2+ethanol. This work also discusses solutions to remedy the enzymatic browning, such as heat treatment and the addition of naturally rich fruit powders as anti-browning agents.Apples preparation phases are real transformation steps which it’s necessary to optimize and master to preserve all the antioxidant properties of fruits and vegetables byproducts. Our works also highlight more functional properties of apple peels as a stabilizing emulsions agent. The impact of extraction parameters was demonstrated by the exploration of several conditions such as the loaded weight, the grinding, the protocol as well as the temperature and composition of supercritical fluids

De nombreux procédés de la recherche et de l'industrie utilisent l'extraction liquide-liquide, technique qui permet la séparation sélective de produits au sein d'un mélange. À cet effet, deux liquides non miscibles sont mis en contact : une phase aqueuse et une phase organique, l'une contenant généralement une molécule extractante capable de transférer les éléments désirés à l'autre. Le transfert se produit à la surface de contact entre les deux phases. Après le transfert, les deux phases sont séparées par décantation. Dans la pratique, ces opérations sont effectuées dans des appareils industriels. Pour optimiser et comprendre le fonctionnement de ces dispositifs, il est important de déterminer les caractéristiques fondamentales de l'émulsion. Il s'agit notamment des paramètres liés à la vitesse des écoulements ainsi que ceux liés au mélange des fluides comme l'aire interfaciale, le taux de rétention, ou la distribution en taille de la population de gouttes. Plusieurs techniques d'imagerie peuvent être utilisées pour les mesurer. L'une d'elles, l'holographie numérique, est bien connue pour permettre la reconstruction complète en 3D d'un écoulement à partir d'une seule acquisition. Ce travail de thèse traite d'une application de l'holographie numérique en ligne directement sur des gouttes en mouvement dans une phase liquide continue. La taille des gouttes a imposé l'exploration d'un régime de diffraction peu étudié à ce jour. Dans ce domaine, le modèle du disque opaque classiquement employé n'est pas valide et un meilleur accord est obtenu avec un modèle mixte lui associant une lentille mince. La focalisation des hologrammes est réalisée via une méthode dédiée et automatique qui a été établie à partir d'une étude complète de la littérature. Dans un deuxième temps, afin de mesurer des rétentions plus élevées, elle est complétée par une approche inverse permettant de corriger les mauvais positionnements et de restituer les gouttes non détectées. Ce traitement a été appliqué à des résultats expérimentaux, sur un dispositif de référence produisant des gouttes calibrées, et comparé à des mesures indépendantes. Ces essais ont validé la pertinence de l'holographie pour la caractérisation des émulsions
Several processes used in research and industry are based on liquid-liquid extraction, a method designed for selective separation of products in a mixture. In liquid-liquid extraction, two immiscible liquids are contacted: an aqueous phase and an organic phase, one of which generally contains an extractant molecule capable of transferring the desired elements to the other phase. The transfer occurs at the contact surface between the two phases. After transfer, both phases are separated by settling. In practice, these operations are performed in industrial apparatus. In order to optimize the operation of these devices, it's important to determine the fundamental characteristics of the emulsion. These include parameters related to the fluid flow velocity as well as parameters related to fluid mixing such as the interfacial area, hold-up, and size distribution of the droplets population. Numerous imaging techniques can be used to measure these parameters. One of them, digital holography, is well-known for allowing complete reconstruction of information about a 3D flow in a single shot. This PhD work deals with a direct application of digital in line holography to droplets rising in a continuous liquid phase. The droplet size imposes a regime of intermediate-field diffraction hardly explored to date. Acquired diffraction patterns show that the usual dark disk model is not valid and that good agreement is obtained with a mixed model coupling thin lens with opaque disk. Hologram focusing is nevertheless performed with a dedicated automated method. A literature review has been conducted to identify the sharpest autofocus function for our application. In a second step, in order to measure high retention rates, an inverse problem approach is applied on all the outliers and missing droplets. This hologram restitution treatment has been applied to experimental results with a comparison to independent measurements. The main results obtained with calibrated droplets are presented detailing the test device and instrumentation. They have validated the relevance of holography for the characterization of emulsions

Desarrolla un sistema conservante preparado a base de un extracto vegetal y tres aceites esenciales, para la formulación de emulsiones cosméticas. En una primera etapa se formuló el sistema conservante mezclando, en partes iguales, insumos comerciales de extracto de semillas de Citrus paradisi, con aceites esenciales de Luma chequen, Melaleuca alternifolia y Cymbopogon citratus, al que se determinó la actividad antimicrobiana, mediante el método de difusión en pocillos, frente a cepas de Escherichia coli (ATCC No. 8739), Pseudomonas aeruginosa (ATCC No. 9027), Staphylococcus aureus (ATCC No . 6538) Candida albicans (ATCC No. 10231) y Aspergillus niger (ATCC No. 16404). En una segunda etapa se aplicó el sistema conservante en una emulsión tipo O/W a tres concentraciones: 0,25; 0,50 y 1,0 % y se determinó la eficacia antimicrobiana según norma ISO 11930:2012. Finalmente se evaluó el desempeño del sistema conservante, en condiciones de estabilidad, sometiendo la emulsión O/W y otra emulsión W/O con 0,25% del conservante desarrollado, a 40 °C por 6 meses. Los resultados de actividad antimicrobiana para el sistema conservante fueron (halo de inhibición “mm”): E. coli: “13,00 ± 0,00”; S. aureus: “inhibición total”; P. aeruginosa: “12,33 ± 0,47”; C. albicans: “10,33 ± 0,47” y A. niger: “26,67 ± 0,47”. Los resultados de la prueba de eficacia antimicrobiana, para las emulsiones O/W con 0,25; 0,50 y 1,0 % de conservante desarrollado cumplen con el criterio A, de la norma ISO 11930:2012. Los resultados de la prueba de eficacia antimicrobiana, en condiciones de estabilidad, para las emulsiones O/W y W/O con 0,25% del conservante desarrollado, también cumplen con el criterio enunciado. Se concluye que el sistema conservante propuesto, posee actividad antimicrobiana frente a todos los microorganismos evaluados, además de eficacia como sistema conservante, desde una concentración de 0,25 %; brindando protección eficaz frente a contaminación microbiológica, según norma ISO 11930:2012.
Tesis

Evalúa la composición química, actividad antimicrobiana y actividad fotoprotectora UVB en emulsiones dermocosméticas del aceite esencial de Peperomia galioides Kunth. El aceite esencial se obtuvo mediante un sistema de destilación por arrastre de vapor con agua. El análisis de los componentes químicos se realizó por Cromatografía de Gases acoplada a Espectrometría de Masas (CG/MS). La actividad antioxidante se realizó por los métodos DPPH y ABTS. La actividad antimicrobiana fue evaluada por el método de microdilución y difusión en agar. La actividad fotoprotectora de la emulsión dermocosmética fue evaluada espectrofotométricamente en el rango UVB entre 290 a 320 nm. Se obtuvo un rendimiento de 0,235% v/p del aceite esencial; la muestra presentó 86 y 14 componentes químicos mediante inyección liquida y headspace respectivamente. La capacidad antioxidante equivalente al Trolox (TEAC) mediante el ensayo del radical DPPH fue 0,04196 μg Trolox/mg de aceite esencial. El TEAC mediante el ensayo de ABTS fue de 1,9213 μg Trolox/mg de aceite esencial de Peperomia galioides Kunth “Congona”. La actividad antimicrobiana del aceite esencial mediante microdilución frente a bacterias Gram negativa fue baja, sin embargo, fue efectiva frente a Gram positivos como S. aureus y B. subtilis con un CMI de 20 y 10 uL/mL respectivamente. Las emulsiones dermocosméticas al 1, 5 y 10 % presentaron valores de Factor de Protección Solar (FPS) menores a 1,3. En conclusión, el aceite esencial de Peperomia galioides Kunth tiene moderada actividad antimicrobiana, baja actividad antioxidante en comparación al estándar Trolox y un nivel bajo de protección solar en las emulsiones dermocosméticas elaboradas.
Tesis

L'extraction aqueuse des lipides de la graine de tournesol est étudiée en contacteur agité. La diffusion à l'intérieur des particules est le facteur limitant de l'échange de matière. Les protéines sont impliquées dans l'entraînement et la stabilisation des lipides par l'eau. Le fractionnement de la plante entière est également étudié avec l'eau en extrusion bi-vis. Un extrait et un raffinat sont obtenus séparément et en une seule étape continue. Des rendements d'extraction en huile de 55 % peuvent être obtenus sous forme d'émulsions huile/eau. Leur stabilité est assurée par la présence à l'interface de tensioactifs : les phospholipides et les protéines voire les pectines. Les extraits se composent aussi d'une phase hydrophile. Prépondérante, elle contient des composés hydrosolubles (protéines, pectines…). Riches en fibres, les raffinats présentent une teneur significative en protéines au comportement thermoplastique. Ils peuvent être transformés en agromatériaux par thermomoulage.

This study was aimed at designing an optimised emulsion liquid membrane (ELM) for the extraction of rhodium from precious metal refinery wastewaters. The demulsification process and the structure of the optimised ELM are reported on. Two optimised ELMs were prepared. The first one contained a 30 % solution of toluene in kerosene as diluent with the following concentrations of the ELM components: 30.000 g/L (w/v) polyisobutylene, 10.870 g/L (m/v) of trioctyl amine and 51.001 g/L (m/v) of SPAN 80. The second ELM contained the same diluent, but the concentrations of the other ELM components in it were as follows: 20.000 g/l of polyisobutylene, 10.268 g/l trioctyl amine and 50.024 g/l of SPAN 80. The stripping phase was the same in both optimised ELMs, namely a 2 M solution of HNO3. The stripping phase and the diluent solution were mixed together in ratios of 1:1 and 2:1, respectively. Two methods were used to characterise the microdroplet diameters, i.e. optical microscopy and the Zeta-sizer. For the t-test, the p-value of 0.3018 at 5 % level of significance showed that there was statistically no significant difference in the mean micro-droplet size for 1:2 ELMs containing 20 g/l and 30 g/l of polyisobutylene after 40 minutes of emulsification. The best demulsification results were obtained using the chemical demulsification with polyethylene glycol with molecular weight of 400 g/mol (PEG 400) at 50 ± 1 °C for 24 hours. However, significant carryover of toluene, trioctyl amine and polyethylene glycol into the aqueous phase was observed.

碩士
逢甲大學
化學工程學所
90
Abstract Emulsion liquid membrane (ELM) system is a novel technology with characteristics of separation, concentration and immobilization. It has been widely investigated by many researchers as an advanced extraction technique and is considered to have potential applications in the extraction and concentration for heavy metal ions. However, the stability and the extraction efficiency of ELM are suffered from mechanical breakage and osmotic swelling and the problems are still open to study. Recently, the nanocomposite materials are of widespread importance and the development of novel methods for producing materials at the nanometer scale is of intense current interest. It is the purpose of this study to examine the feasibility of applying the ELM system to synthesize the CdS nanoparticles in the process of extraction of Cd2+ ions. In order to investigate the stability and efficiency of the process of Cd2+ extraction and the possibility of synthesizing CdS nanoparticles in the ELM system, two parts of experimental works, i.e., one is the extraction experiment of Cd2+ ions and the other is the synthesis experiment of CdS nanoparticles, are conducted in this study. In the extraction experiment of Cd2+ ions, the effects of emulsion membrane parameters such as surfactant concentration, carrier types and concentration, solvent and polymer additive (e.g., polyisobutylene) are extensively discussed to examine their influences on the stability and the extraction efficiency of the ELM system. It is found that the ELM system with toluene as the oil solvent is the most stable system. The results show that the percentage of extraction of Cd2+ ions in such system is about 40% at 60 min and the trend of the extraction curve is still rising when the compositions of emulsion containing 4wt% Span 80, 7 wt% TBP and 5wt% polyisobutylene. As for the synthesis experiment of CdS nanoparticles, three different methods, i.e., direct precipitation method, ELM extraction method, and double W/O emulsion method, are adopted to examine their influences on the properties of CdS nanoparticles. Samples are characterized by structural analysis (XRD, TEM) and optical analysis (UV/VIS, PL). The results show that CdS nanoparticles prepared by the double W/O emulsion method have the smallest particle size and exhibit most significant quantum size effects. It is also found that the crystallites of the prepared CdS nanoparticles are strongly influenced by the existence of carrier TBP. Surprisingly, the crystallite of CdS nanoparticles is in cubic phase in the system with carrier TBP, while it is in hexagonal form in the system without carrier TBP. However, surfactant Span 80 in the concentration range discussed in this study (4~6 wt%), has little effect on the properties of CdS nanoparticles. From the preliminary results of this study, it is found that the particle sizes of the prepared CdS nanoparticles can be easily controlled in the range of 5~25 nm under mild conditions. This evidences the feasibility of applying the ELM process to the synthesis of CdS nanoparticles.

The aim of this project was to produce a potential feedstock for biodiesel by developing a process to extract oil from yellow mustard seeds using aqueous and isopropyl alcohol extraction. The aqueous extraction of yellow mustard flour was performed at pH 11 using 4:1 water to flour ratio and constant stirring at room temperature for 30min, with a second washing stage. Oil was separated as oil-in-water emulsion with 37% oil recovery from the flour. The oil in the emulsion was then extracted with isopropyl alcohol. Single and multiple stage extractions were evaluated and the optimal conditions were four-stage extraction at 2:1 IPA:Oil weight ratio, with 96.3% oil recovery from the emulsion. A preliminary evaluation of the final solution of isopropyl alcohol, water and yellow mustard oil concluded that it is indeed a potential feedstock for biodiesel, however it needs to be further processed to meet optimal conditions for transesterification.

碩士
國立臺北科技大學
化學工程所
94
The emulsification liquid membrane system is a noble separation method it can be used for separation, concentration and solidification, etc.. It finds eotentiol application in recovery of heavy metal ion, extraction. But emulsion liquid membrane will break due to swelling, which in turn reduces liquid membrane stability and extract efficiency. This study discussed how to increase the extraction efficiency, of emulsion liquid membrane system and the use of emulsion liquid membrane for synthesizing ZnS nanometer. Extract the experiment part, change the active pharmaceutical kind of interface and consumption, pharmaceutical consumption, oil looks consumption in year different from thickness of foreign minister solution pH value, etc. and operate the condition mainly, probe into the emulsification liquid membrane and extract efficiency, and find out and operate the condition association bestly. The active pharmaceutical of interface used, for Span 20, Span 80 in the dissolving surfactant concentration of interface of oil of Span series (mountain pear candy alcohol ester), phosphoric acid (D2EHPA) year pharmaceutical with acid extraction two pharmaceutical (2 - second base own base), the kerosene is the oil looks solvent, ZnCl2 is the foreign minister solution. The experimental result shows, under the same condition, surface-active agent Span 20 of interface is better than Span 80 extracts efficiency, it is the most ideal that consumption is controlled in 2wt%. Inclusive to increase the extracting amount to obviously increase with the pharmaceutical D2EHPA content of year in the organic solution, and also increase ZnCl2 extracting amount of Zn2+ ion to increase with the thickness pH value of foreign minister''s aqueous solution. In the section on the use of emulsification liquid membrane system to for synthesizing ZnS, we probed into the influence of synthetic method and solution conposition on the ZnS particles formed XRD and TEM were used to explone the structure. Optical analyses such as UV/VIS and PL and dynamic light scattering spectrometer, were also used to measure the size of the particles.

Recientemente, la semilla de chía (Salvia hispanica L.) ha sido redescubierta como una importante fuente de ácidos grasos omega-3, proteínas, fibra dietética y antioxidantes, a partir de la cual puede obtenerse aceite con una elevada proporción de ácidos grasos esenciales. Su incorporación en la dieta permite disminuir la incidencia de enfermedades coronarias, refuerza el sistema nervioso; la fibra dietaria es una valiosa alternativa para regular el tránsito intestinal, lo cual ayuda a prevenir la obesidad, el cáncer de colon, así como los elevados niveles de colesterol y de glucosa en sangre. En nuestro país, la creciente expansión de su cultivo en las provincias del noroeste puede representar un aporte tendiente a la diversificación de la producción agrícola con el consecuente impacto socioeconómico en dicha región. Por otra parte, Argentina es uno de los principales productores y exportadores de aceite de girasol (Helianthus annuus L.) y la industria local se destaca por su avanzada tecnología y alta competitividad. Asimismo, el girasol es el segundo cultivo oleaginoso en importancia a escala nacional luego de la soja. El 92% del girasol producido en la Argentina es procesado, siendo exportado el 70% como aceite crudo a granel y harina proteica y el 30% restante como aceite refinado. Los aceites comestibles constituyen un componente importante en nuestra alimentación, cuya variedad y consumo depende de la disponibilidad de cada país y región. La composición de los aceites varía considerablemente en el aporte de ácidos grasos saturados, monoinsaturados y poliinsaturados y particularmente, en el tenor de ácidos grasos omega-6 y omega-3. La nutrición en el mundo occidental se caracteriza por una elevada ingesta de ácidos grasos omega-6 y un bajo consumo de ácidos grasos omega-3, debido mayoritariamente al origen vegetal de los aceites que se producen y al bajo consumo de pescados grasos. De esta forma, la relación omega-6:omega-3 está alejada de la que recomienda la FAO/OMS. En virtud de ello, es posible preparar aceites con relaciones omega-6:omega-3 muy cercanas a las recomendadas, desarrollando productos que contengan mezclas de aceites con una adecuada composición de ácidos grasos. En nuestro país, debido a la gran producción de aceite de girasol, es interesante la revalorización de los subproductos generados en el proceso de extracción y/o refinación del mismo. Entre ellos se encuentran las gomas, constituidas por una mezcla de fosfolípidos, agua y restos de aceite. La posterior deshidratación de las mismas da lugar al subproducto denominado lecitina. Cada fosfolípido constituyente contribuye a la funcionalidad de la lecitina, por lo que la modificación de su estructura y/o de su concentración posibilita ampliar las propiedades funcionales de las mismas. En el Capítulo I se presenta una introducción sobre la chía y el girasol, describiendo el origen y los antecedentes históricos de estas especies, las principales características botánicas, así como la composición química de las semillas y sus respectivos aceites. Además, se describe el proceso de obtención de los aceites vegetales y de la lecitina, la cual es principalmente utilizada como agente emulsificante en la industria alimentaria. Por último, se describen los mecanismos de formación, estabilidad y desestabilización de las emulsiones. En el Capítulo II se detalla el proceso de fraccionamiento de lecitina nativa de girasol, mediante el empleo de diferentes soluciones etanol-agua y distintos niveles de pH del solvente de extracción. Además, se analizan las propiedades funcionales de las fracciones enriquecidas en fosfatidilcolina PC, como agentes emulsificantes de emulsiones O/W. En el Capítulo III se estudia la obtención, caracterización, estabilidad oxidativa y condiciones de almacenamiento más adecuadas de aceites mezcla girasol-chía, los cuales presentan relaciones omega-6:omega-3 acordes a las recomendadas por la FAO/OMS, evaluando la eficiencia de la adición de antioxidantes (extracto de romero, palmitato de ascorbilo y su mezcla) con respecto al deterioro oxidativo de los mismos. Además, se presentan los resultados del análisis sensorial. En el Capítulo IV se evalúa la estabilidad física de emulsiones O/W formuladas con aceites mezcla girasol-chía, lecitinas modificadas de girasol mediante “deoiling” y fraccionamiento (agente emulsificante) y mucílago de chía (agente estabilizante). Finalmente, se exponen las Conclusiones generales obtenidas a partir de este trabajo de Tesis y en base a ellas, las Perspectivas futuras.