The majority of state-of-the-art polymeric membranes for industrial or medical applications are fabricated by phase inversion. Complexation induced phase separation (CIPS)—a surprising variation of this well-known process—allows direct fabrication of hybrid membranes in existing facilities. In the CIPS process, a first step forms the thin metal-rich selective layer of the membrane, and a succeeding step the porous support. Precipitation of the selective layer takes place in the same solvent used to dissolve the polymer and is induced by a small concentration of metal ions. These ions form metal-coordination-based crosslinks leading to the formation of a solid skin floating on top of the liquid polymer film. A subsequent precipitation in a nonsolvent bath leads to the formation of the porous support structure. Forming the dense layer and porous support by different mechanisms while maintaining the simplicity of a phase inversion process, results in unprecedented control over the final structure of the membrane. The thickness and morphology of the dense layer as well as the porosity of the support can be controlled over a wide range by manipulating simple process parameters. CIPS facilitates control over (i) the thickness of the dense layer throughout several orders of magnitude—from less than 15 nm to more than 6 μm, (ii) the type and amount of metal ions loaded in the dense layer, (iii) the morphology of the membrane surface, and (iv) the porosity and structure of the support. The nature of the CIPS process facilitates a precise loading of a high concentration of metal ions that are located in only the top layer of the membrane. Moreover, these metal ions can be converted—during the membrane fabrication process—to nanoparticles or crystals. This simple method opens up fascinating possibilities for the fabrication of metal-rich polymeric membranes with a new set of properties. This dissertation describes the process in depth and explores promising applications: (i) catalytic membranes containing palladium nanoparticles (PdNPs), (ii) antibiofouling tight-UF membranes containing silver chloride (AgCl) crystals, and (iii) palladiumrich PBI hollow fibers for H2 recovery.

In today’s fast adjustment to renewable energy, new battery technologies are needed to meetthe ever-growing demands of energy storage. Cheaper and easier to produce materials areneeded, as well as materials with a lower environmental impact. One new and interestingtechnology is the dual-ion battery, and more specifically the aluminum dual-ion battery. Thisbattery uses cheap and abundant aluminum together with a graphitic cathode to work. However,a lot of research today uses expensive and sophisticated cathode materials to make this type ofbattery work. Therefore, this thesis focuses on creating a cheap and easy to produce graphitecathode material through the phase inversion method for the use in aluminum dual-ionbatteries, that is also freestanding for better energy density. Graphene is also used as anadditive to improve the electrical conductivity of the material, and the material is later tested in afull cell with the typical ionc liquid electrolyte EMImCL/AlCl4.Through phase inversion, a freestanding graphite cathode is produced with 8 wt% PVDF binderand 0.4 wt% graphene. The material has a porous structure and an enhanced electricalconductivity with the graphene added. Through CV cycling and symmetric Al-Al tests the batteryreactions are shown to work. However, when cycling the cell with a constant current there areproblems, probably coming from some sort of soft shorting or side reactions. It is revealed thatapart from the expected reactions, Ni dissolution from the contact tabs also takes place, andmay cause problems. Further tests are needed to validate if this material works. However,because no new active materials have been introduced to the battery chemistry, it is reasonableto believe that the battery will work with some small changes.Tek nisk-naturvetensk apliga fak ulteten, Upps ala universitet. Utgiv nings ort U pps al a/Vis by . H andledare: Anwar Ahniy az , Äm nesgranskar e: D aniel Brandell, Ex aminator: Lena Klintberg

No description available.

Agitated dispersions of one liquid in another immiscible liquid are widely used in chemical industry in operations such as liquid-liquid extraction, suspension polymerisation, and blending of polymers. When holdup of the dispersed phase is increased, in an effort to increase the productivity, at a critical holdup, the dispersed phase catastrophically becomes the continuous phase and vice versa. This phenomenon is known as phase inversion. Although the inversion phenomenon has been studied off and on over the past few decades, the mechanism of phase inversion (PI) has yet not become clear. These studies have however brought out many interesting aspects of PI, besides unravelling the effect of physical and operational variables on PL Experiments show that oil-in-water (o/w) and water-in-oil (w/o) dispersions behave very differently, e.g water drops in w/o dispersions contain oil droplets in them, but oil drops in o/w dispersions contain none, dispersed phase hold up at which inversion occurs increases with agitation speed for w/o dispersions but decreases for o/w dispersions. A common feature of both types of dispersions however is that as agitation speed is increased to high values, inversion holdups reach a constant value. A further increase in agitation speed does not change inversion hold up. Although this finding was first reported a long time ago, the implications it may have not received any attentions. In fact, the work reported in the literature since then does not even mention it. The present work shows that this finding has profound implications. Starting with the finding that at high agitation speed inversion hold up does not change with agitation speed, the present work shows that inversion hold up also does not change with agitator diameter, type of agitator and vessel diameter. In these experiments, carried out in agitated vessel, energy was introduced as a point source. The experiments carried out with turbulent flow in annular region of two coaxial cylinders, inner one rotating, in which energy is introduced nearly uniformly throughout the system, show that the inversion holdup remains unchanged. These results indicate that constant values of inversion holdups for a given liquid-liquid systems (o/w and w/o) are properties of the liquid-liquid systems alone, independent of geometrical and operational parameters. A new hypothesis is proposed to explain the new findings. Phase inversion is considered to occur as a result of imbalance between breakup and coalescence of drops. Electrolytes, which affect only coalescence of drops, were therefore added to the system to investigate the effect of altering coalescence of drops on phase inversion. The experiments performed in the presence of electrolyte KI at various concentrations indicate that addition of electrolyte increases the inversion holdup for both o/w and w/o dispersions for three types of systems: non polar-water, polar-water and immiscible organic-organic. Higher the concentration of electrolyte used, higher was the holdup required for phase inversion. These findings indicate that while the addition of electrolyte increases coalescence of drops in lean dispersions, it has exactly opposite effect on imbalance of breakage and coalescence of drops at high holdups near phase inversion point. The opposite effect of electrolytes in lean and concentrated dispersions could be explained qualitatively, but only in part in the light of a new theory, involving multi-particle interactions. The phase inversion phenomenon is quantified in a simple manner by testing the breakage and coalescence rate expressions available in literature. It has been found that, equilibrium drop size (where breakage and coalescence events are in dynamic equilibrium) approaches infinity near phase inversion holdup which is not an ex perimentally observed fact. To capture the catastrophic nature of phase inversion, two steady state approach is proposed. The two steady states namely the stable steady state and unstable steady state, are achieved by modifying the expression for coalescence frequency on the basis of (i) shear coalescence mechanism and, (ii) recognising the fact that at high dispersed phase holdup the droplets are already in contact with each other at all times and hence rendering the second order coales cence process to a first order one. Using two steady states approach, catastrophic phase inversion is shown to occur at finite drop size.

The oil and gas industry need for high performing and low cost multiphase meters is ever more justified given the rapid depletion of conventional oil reserves. This has led oil companies to develop smaller/marginal fields and reservoirs in remote locations and deep offshore, thereby placing great demands for compact and more cost effective soluti8ons of on-line continuous multiphase flow measurement. The pattern recognition approach for clamp-on multiphase measurement employed in this research study provides one means for meeting this need. Cont/d.

Escoamentos gás-líquido assim como escoamento líquido-líquido-gás em duto de geometria anular estão presentes em muitas aplicações industriais, por exemplo, em poços de petróleo direcionais. No entanto, até mesmo características globais de escoamento gás-líquido nessa geometria, como os padrões de escoamento ou gradiente de pressão, não são ainda totalmente compreendidas. E ainda, informações são escassas quando se refere a escoamento trifásico nessa geometria, cuja aplicação está relacionada ao fenômeno de inversão de fase, que é de extrema importância não apenas para ao setor petrolífero, como para a indústria alimentícia. O presente estudo experimental tem como objetivo avaliar o escoamento líquido-gás, apresentar dados inéditos de escoamento gás-líquido para três viscosidades de óleo, além de avaliar o fenômeno de inversão de fase em escoamento ascendente vertical em duto anular de grande diâmetro. Um aparato experimental inclinável com 10,5 m de comprimento foi projetado e construído para este trabalho. As dimensões radiais do duto anular estão em escala real, conforme se verifica em poços de petróleo e gás. A investigação em escoamento gás-líquido foi conduzida utilizando água, óleo e ar comprimido como fluidos de trabalho em escoamento ascendente vertical em duas geometrias: (i) um tubo com diâmetro de 95 mm e (ii) um duto de configuração anular e concêntrico, com diâmetro hidráulico de valor igual ao diâmetro do tubo. A avaliação do fenômeno de inversão de fase em escoamento trifásico foi conduzida em condições equivalentes em três geometrias: (i) tubo vertical menor com diâmetro de 50 mm, (ii) tubo com diâmetro de 95 mm e (iii) um duto anular concêntrico. Padrões de escoamento, queda de pressão e fração volumétrica de fase foram obtidos para ambos os escoamentos gás-líquido e líquido-líquido-gás. Os dados coletados nesse trabalho são de grande importância para o desenvolvimento de novas correlações de fechamento, que são essenciais para o projeto otimizado de poços de petróleo. Dados inéditos de escoamento bifásico óleo-gás são apresentados, bem como um estudo pioneiro em inversão de fase em escoamento trifásico com velocidade superficial de gás e viscosidade do óleo elevadas. / Two-phase flows as well as three-phase flow in annular geometry are present in many industrial applications, for example in oil directional wells. However, even global characteristics of gas-liquid flow in this geometry, such as flow patterns and pressure gradient are not fully understood. Moreover, information is scarce when it refers to three-phase flow in this geometry, which application is related to the phase inversion phenomenon, which is of extreme importance and not only for the oil industry. This experimental study aims to evaluate the liquid-gas flow, present new data from gas-liquid flow for three oil viscosities and evaluate the phase inversion phenomenon in vertical upward flow in large diameter annular duct. An experimental apparatus with 10.5 m length was designed and built for this work. The radial dimensions of the annular duct are similar to full scale, as observed in oil and gas wells. The investigation into gas-liquid flow was conducted using water, oil and compressed air as working fluids in an ascending vertical flow in two geometries: (i) a tube with 95 mm diameter and (ii) a concentric annular duct with hydraulic diameter equivalent to the tube internal diameter. The evaluation of the phase inversion phenomenon in three-phase flow was conducted under equivalent conditions for three geometries: (i) smaller vertical tube with 50 mm of internal diameter, (ii) tube with 95 mm of internal diameter and (iii) concentric annular duct with hydraulic diameter of 95 mm. Flow patterns, pressure drop and volumetric phase fraction were obtained for both gas-liquid and gas-liquid-liquid flows. The data collected in this study are of great importance for the development of new closing correlations, which are essential for the optimized design of oil wells. New two-phase flow data for three oil viscosities, not found in the literature, are presented as well as a pioneer study in three-phase-flow phase inversion with high oil viscosity and high superficial gas velocity.

Este trabalho de Mestrado teve por objetivo avaliar a atividade antifúngica in vitro e em queijo Minas Padrão de duas formulações (A e B) de nanoemulsões encapsulando óleo essencial de orégano (Origanum vulgare) produzidas pelo método da temperatura de inversão de fases (método PIT). Cladosporium sp., Fusarium sp. e Penicillium sp. foram os fungos identificados nas amostras de queijo Minas Padrão deteriorados. Tais cepas foram utilizadas na avaliação da atividade antifúngica in vitro e em queijo Minas Padrão do óleo de orégano nanoemulsionado. Nos testes in vitro foram determinadas as concentrações mínimas inibitórias (CMI) do óleo essencial de orégano puro e nanoemulsionado sobre o Cladosporium sp., Fusarium sp. e Penicillium sp. Foram utilizadas fatias de queijo Minas Padrão para avaliar o efeito inibitório das nanoemulsões contendo óleo essencial de orégano. Por último foi avaliado o efeito inibitório das nanoemulsões durante o processo de maturação de queijos Minas Padrão. Determinaram-se valores de CMI para óleo essencial puro de 0,2; 0,3 µg/ml para Fusarium sp. e Penicillium sp., respectivamente. Enquanto para as duas formulações de nanoemulsão; os valores de CMI dependeram da quantidade de óleo essencial de orégano que estava contido nelas, obtendo-se valores de 0,26; 0,11 e 1,62 µg/ml para a formulação A de óleo de orégano nanoemulsionado sobre Cladosporium sp., Fusarium sp. e Penicillium sp., respectivamente, e CMIs de 0,32; 0,1 e 0,8 µg/ml para a formulação B de nanoemulsão sobre os mesmos gêneros de fungos. Os ensaios nas fatias de queijo evidenciaram que o efeito das CMIs, quando aplicadas na matriz alimentícia, foi nulo, permitindo o desenvolvimento normal dos fungos avaliados, da mesma forma se determinou a importância da atividade de água no crescimento fúngico. Já nos queijos em ambiente de maturação o efeito inibitório do óleo de orégano foi pouco satisfatório, o que indicou a importância do controle dos demais parâmetros ambientais no ambiente de maturação. Pode-se concluir que o óleo essencial de orégano nanoemulsionado apresentou efeito inibitório contra os gêneros de fungos avaliados. Quando controlados parâmetros ambientais como temperatura de armazenamento e atividade de água, seu efeito inibitório pode ser amplamente melhorado, apresentando-o como potencial alternativa na conservação dos alimentos. / This Master Thesis aimed to evaluate the in vitro antifungal activity and in Minas Padrão cheese of two formulations (A and B) of nanoemulsions encapsulating essential oil of oregano (Origanum vulgare) produced by the method of phase inversion temperature (PIT method). Cladosporium sp., Fusarium sp. and Penicillium sp. fungi were identified in deteriorated cheese samples. These strains were used in the evaluation of antifungal activity of oregano essential oil nanoemulsions, both in vitro and in cheese. Minimum inhibitory concentrations (MIC) of essential oil of pure oregano oil and nanoemulsions were determined. Cheese slices were used to evaluate the inhibitory effect of nanoemulsions containing essential oil of oregano. Finally the inhibitory effect of encapsulated oregano oil was tested during cheese ripening. MIC values determined for pure essential oil were 0.20 and 0.3 µg/ml for Fusarium sp. and Penicillium sp., respectively. As for the two nanoemulsion formulations, MIC values depended on the amount of essential oil of oregano which was contained therein, and the values for formulation A were 0.26, 0.11 and 1.62 µg/ml for Cladosporium sp., Fusarium sp. and Penicillium sp, respectively. For formulation B, the values of MIC were 0.32, 0.10 and 0.80 µg/ml. The tests on the cheese slices showed that the effect of MIC when applied in the food matrix was null, as the fungi growth was not avoided. As for the tests during cheese ripening, the inhibitory effect of oregano oil in nanoemulsions was unsatisfactory, which indicated the importance of controlling other environmental parameters in the maturation chamber. It can be concluded that the nanoemulsions of essential oil presented inhibitory effect against the genera of fungi evaluated. Controlled environmental parameters such as storage temperature and water activity, its inhibitory effect can be highly improved, and the nanoemulsions of oregano oil can be seen as a potential system for food preservation.

Ce travail porte sur l’inversion de phase catastrophique induite par l’agitation continue d’un système anormal eau-huile-surfactif, sans addition de phase, afin de réaliser des émulsions eau-dans-huile concentrées et finement dispersées. Les suivis rhéologiques et conductimétriques des systèmes sous agitation indiquent que l’inversion passe, en général, par la formation d’une émulsion multiple e/H/E dans laquelle une partie de la phase continue est inclue comme gouttelettes dans les gouttes de phase dispersée. Ainsi, le volume apparent de phase dispersée augmente jusqu’à atteindre une valeur critique à laquelle l’inversion se produit. Afin de maîtriser ce processus, l’influence de variables de formulation, composition et agitation sur le mécanisme d’inversion et sur ses paramètres caractéristiques a été étudié. Les données recueillies permettent de choisir les conditions de formulation et de procédé pour préparer, en un temps minimal, des émulsions E/H avec des propriétés requises. / This study deals with the catastrophic phase inversion produce by continuous stirring of an abnormal water-oil-surfactant system, without internal phase addition, in order to prepare concentrated and fine water-in-oil emulsions. The simultaneous conductivity and viscosity measurements of the system under stirring show that generally, the inversion takes place through the formation of a multiple w/O/W emulsion in which a portion of the external phase is continuously included as droplets in the dispersed phase drops. Consequently, the dispersed phase apparent volume increases until a critical value is reached and the inversion is triggered. In order to control this process, the influence of formulation, composition and stirring variables on the inversion mechanism and on its characteristic parameters is studied. The data collected can be used to prepare, in a minimal time, emulsions with required properties, by controlling the formulation and process conditions.

The oil and gas industry need for high performing and low cost multiphase meters is ever more justified given the rapid depletion of conventional oil reserves. This has led oil companies to develop smaller/marginal fields and reservoirs in remote locations and deep offshore, thereby placing great demands for compact and more cost effective soluti8ons of on-line continuous multiphase flow measurement. The pattern recognition approach for clamp-on multiphase measurement employed in this research study provides one means for meeting this need. Cont/d.

La technologie supercondensateur a fait l'objet d'un grand intérêt ces dernières années. Cependant, tandis qu'une grande attention a été donnée aux électrodes, aux électrolytes et aux électrolytes de polymère gélifiée, peu d'études ont été centrées sur l'amélioration des séparateurs macroporeux. Dans le cadre du projet SEPBATT/DURAMAT, les séparateurs macroporeux à base de poly(fluorure de vinylidène) (PVdF) ont été préparés par inversion de phase, pour les supercondensateurs. Nos membranes présentent également une bonne stabilité thermique, en revanche leurs propriétés mécaniques sont significativement plus faibles que celles des membranes commerciales. De plus le séparateur PVdF de porosité 80% rempli par l'électrolyte à base d'AN atteint, à 25°C, 18mS/cm, tandis que dans les mêmes conditions mais avec le séparateur commercial en cellulose, la conductivité n'atteint que 10 mS/cm. Ce travail a été complété par l'étude de techniques de renforcement (addition de composites, réticulation par l'irradiation) appliquées aux membranes précédemment préparées, pour augmenter leur tenue mécanique. Ces membranes ont montré un renforcement des propriétés mécaniques sans nuire aux propriétés de conduction ionique (15 mS/cm). / Abstract In recent years a strong interest has been devoted to supercapacitor technology. However, while great attention has been paid to electrodes, electrolytes and gel polymer electrolytes, only few reports have been dedicated to macroporous separators. Hereby, in the frame of project SEPBATT/DURAMAT, macroporous poly(vinylidene fluoride) (PVdF) based separators were prepared by phase inversion technique for applications of supercapacitors. Their mechanical properties are relatively lower than those of commercial membranes nevertheless such membranes exhibit good thermal stability. Whereas commercial cellulose based separators filled with tetraethyl ammonium tetrafluoroborate + CH3CN electrolyte show 10 mS/cm (at 25°C), our PVdF macroporous separators exhibit significantly higher conductivity (18 mS/cm) under the same conditions. This study was completed with application of reinforcement techniques (addition of composites, crosslinking by irradiation) on to previously prepared membranes in order to increase their mechanical strength. Reinforced membranes showed good high mechanical strength whereas the ionic conductivity is almost maintained (15mS/cm).