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The use of foam-forming surfactants offers promise to improve sweep efficiency and mobility control for enhanced oil recovery (EOR). This thesis provides an in depth understanding of transport of surfactant and foam through porous media using a combination of laboratory experiments and numerical simulations. In particular, there are several issues in foam EOR processes that are examined. These include screening of surfactant adsorption onto representative rock surfaces, modeling of foam flow through porous media, and studying the effects of surface wettability and porous media heterogeneity. Surfactant adsorption onto rock surfaces is a main cause of foam chromatographic retardation as well as increased process cost. Successful foam application requires low surfactant adsorption on reservoir rock. The focus of this thesis is natural carbonate rock surfaces, such as dolomite. Surfactant adsorption was found to be highly dependent on electrostatic interactions between surfactants and rock surface. For example, the nonionic surfactant Tergitol 15-S-30 exhibits low adsorption on dolomite under alkaline conditions. In contrast, high adsorption of cationic surfactants was observed on some natural carbonate surfaces. XPS analysis reveals silicon and aluminum impurities exist in natural carbonates, but not in synthetic calcite. The high adsorption is due to the strong electrostatic interactions between the cationic surfactants and negative binding sites in silica and/or clay. There are a number of commercial foam simulators, but an approach to estimate foam modeling parameters from laboratory experiments is needed to simulate foam transport. A one-dimensional foam simulator is developed to simulate foam flow. Chromatographic retardation of surfactants caused by adsorption and by partition between phases is investigated. The parameters in the foam model are estimated with an approach utilizing both steady-state and transient experiments. By superimposing contour plots of the transition foam quality and the foam apparent viscosity, one can estimate the reference mobility reduction factor (fmmob) and the critical water saturation (fmdry) using the STARS foam model. The parameter epdry, which regulates the abruptness of the foam dry-out effect, can be estimated by a transient foam experiment in which 100% gas displaces surfactant solution at 100% water saturation. Micromodel experiments allow for pore-level visualization of foam transport. We have developed model porous media systems using polydimethylsiloxane. We developed a simple method to tune and pattern the wettability of polydimethylsiloxane (PDMS) to generate porous media models with specific structure and wettability. The effect of wettability on flow patterns is observed in gas-liquid flow. The use of foam to divert flow from high permeable to low permeable regions is demonstrated in a heterogeneous porous micromodel. Compared with 100% gas injection, surfactant-stabilized foam effectively improves the sweep of the aqueous fluid in both high and low permeability regions of the micromodel. The best performance of foam on fluid diversion is observed in the lamella-separated foam regime, where the presence of foam can enhance gas saturation in the low permeable region up to 45.1% at the time of gas breakthrough. In conclusion, this thesis provides new findings in surfactant adsorption onto mineral surfaces, in the methodology of estimating foam parameters for reservoir simulation, and in micromodel observations of foam flow through porous media. These findings will be useful to design foam flooding in EOR processes.

Functionalized membranes provide an elegant platform for selective separations and sorptions. In this dissertation, application of functionalized membranes for surfactant and metal sorption studies are discussed. Sorption behavior of surfactants is also studied using quartz crystal microbalance (QCM) and other techniques. Adsorption of the ethoxylated surfactants on polymeric materials (cotton and polyester) and model gold surface was quantified from a non-aqueous siloxane based solvent (D5) and water. The role of ethylene oxide group and the effect of nature of polymeric materials on adsorption behavior was quantified and established. In the case of gold-water interface, the adsorption data was fitted to calculate adsorption/desorption rate constants. The study is important towards applications involving use of the surfactants in cleaning operations. PAA functionalized membranes were prepared and used for separation of the surfactants from the siloxane solvent. Finally the pH sensitivity of the PAA-surfactant complex was verified by successful regeneration of the membrane on permeation of slightly alkaline water. The preparation and application of thiol and sulfonic acid functionalized silica mixed matrix membranes for aqueous phase metal ion sorption is also studied. The functionalized particles were used as the dispersed phase in the polysulfone or cellulose acetate polymer matrix. The effects of the silica properties such as particle size, specific surface area, and porous/nonporous morphology on the metal ion sorption capacity were studied. Silver and ferrous ions were studied for metal sorption capacities. The ferrous ions were further reduced to prepare membrane immobilized iron nanoparticles which are attractive for catalytic applications. One dimensional unsteady state model with overall volumetric mass transfer coefficient was developed to model the metal ion sorption using mixed matrix membrane. The study demonstrates successful application of the functionalized mixed matrix membranes for aqueous phase metal capture with high capacity at low transmembrane pressures. The technique can be easily extended to other applications by altering the functionalized groups on the silica particles. The study is important towards water treatment applications and preparation of membrane immobilized metal nanoparticles for catalytic applications.

<p>Emulsions are advantageous in many applications including healthcare, food science, and detergency due to their ability to disperse one fluid in another, otherwise immiscible fluid. For the same reason, emulsions are also problematic when mixtures of oil and water are undesirable like in industrial wastewater pollution and fuel systems. Whether an emulsion is desirable or not, both benefit from understanding the fundamental relationship of emulsion formation and stability to the physical and chemical properties of the oil-water-surfactant mixture. This work identifies the formation and stability mechanisms of model emulsion systems through the perspective of emulsion prevention for applications in shipboard wastewater (bilge water) treatment. Although experiments in this study were designed to model bilge water systems, their fundamental approach makes them practical for many different applications like food science, pharmaceuticals, and detergency.</p> <p>The impact of salts on emulsion formation and stability to coalescence were studied to understand how emulsions stabilized by ionic surfactant behave in saltwater environments. Droplet size analysis revealed that emulsion stability to coalescence improved with salt concentration. Through interfacial tension and zeta potential measurements, it was found that the addition of salt promoted close surfactant packing and faster surfactant adsorption kinetics at the oil-water interface. This aided in preventing coalescence and created conditions favorable for the formation of a stable Newton black film. Extended DLVO calculations were used to model the interaction energy between droplets and suggested that hydration forces play an important role in stabilizing these systems. These emulsions were then studied under dynamic ageing conditions to observe the impact of motion on emulsion stability. While statically aged emulsions were stable to coalescence, dynamic ageing induced coalescence (increased droplet size) or emulsified the oil droplets (decreased droplet size) depending on the surfactant concentration and energy input during ageing.</p> Formation mechanisms and stability of spontaneous emulsion systems were also investigated. Low molecular weight oils (e.g., toluene, xylenes, and cyclohexane) were found to spontaneously emulsify with nonylphenol polyethoxylated (NPE) and sodium dodecylbenzene sulfonate (SDBS). NPE emulsions spontaneously emulsified via diffusion and micelle swelling and displayed limited stability due to Ostwald ripening. SDBS emulsions also spontaneously emulsified with toluene but only in saltwater environments. As the concentration of salt in the aqueous phase increased, the spontaneity of these emulsions also increased. These systems were analyzed using the hydrophilic lipophilic difference (HLD) theory to evaluate its efficacy for predicting the conditions favorable for spontaneous emulsification. Limitations and practicality of using the HLD model for these systems were also explored.

Ce travail de thèse est une contribution à l’étude des émulsions de Pickering qui ont vu unregain d’intérêt ces dernières années. Bien que l’effet Pickering ait été décrit depuis plus d’un siècle,des études plus systématiques pour comprendre l’activité des particules solides aux interfacesliquide/liquide n’est que partiellement entrepris, surtout en cours de déformation. Plusieurs questionsrestent d’actualité et, en premier, la localisation même des particules à l’interface et le mécanismed’adsorption associé.L’approche proposée dans ce travail de thèse s’inscrit dans cette optique avec en particulier laconsidération d’un événement élémentaire d’une émulsion : une goutte isolée dans une matrice etexaminée suite à un saut de déformation en cisaillement dans un dispositif de cisaillement contrarotatifdéveloppé à PCI. De manière générique, le but est de comprendre la relation entre le comportement dela goutte et la rhéologie complexe (en volume ou en surface) apportée par la dynamique de particulessolides aux interfaces liquide/liquide mobiles. Plusieurs paramètres ont été étudiés en commençant parl’affinité chimique des particules solides avec les phases liquides, la rhéologie des phases liquides, laconcentration et la taille des particules solides ; et pour finir, une attention particulière a été portée àl'effet de la déformation macroscopique et l’âge de la goutte.Plus particulièrement, la mise en évidence de la synergie entre la déformation macroscopiqueet l’âge de la goutte, sur la dynamique d’adsorption des particules à l’interface liquide/liquide et lastructuration de l’interface composée, a permis de proposer une méthodologie pour la modulation de« l’effet mémoire induite par la déformation » lors de la relaxation de la goutte en modifiant lasurface des particules par adsorption de tensioactifs choisis. Ainsi, il a été possible de figer les gouttesliquides dans des formes anisotropes contrôlées. Ce phénomène a été corrélé à une transition liquidesolidede l’interface composée mise en évidence par des mesures des modules rhéologiquesinterfaciaux. Ces derniers ont été, par ailleurs, reliés quantitativement à l’anisotropie des gouttesfigées. / This thesis is a contribution to the study of Pickering emulsions that have seen a renewedinterest in recent years. Although the effect Pickering has been described for over a century, moresystematic studies to understand the activity of solid particles at liquid/liquid interfaces is onlypartially undertaken, especially during flow. Several issues are still relevant and, in particular, thelocation of particles at the interface and the involved adsorption mechanism.The approach proposed in this thesis is to consider an elementary event of an emulsion: asingle droplet in a matrix undergoing a strain jump in a shear flow. This experiment was performed ina counter-rotating shear device developed at PCI. Generically, the aim is to understand the relationshipbetween the behavior of the droplet and the bulk and interfacial rheology induced by the dynamics ofsolid particles at a liquid/liquid interfaces. Several parameters were studied starting with the chemicalaffinity of solid particles with the liquid phases, the rheology of the liquid phases, the concentrationand the size of solid particles, and finally, special attention was paid to the effect of macroscopicdeformation and the age of the interface.More specifically, the demonstration of synergy between the macroscopic strain and the age ofthe interface, the dynamic adsorption of particles at the liquid/liquid interface and the structure of theinterface, allowed to propose a methodology for the modulation of the "memory effect induced by thedeformation" during the relaxation of the droplet by changing the particle surface using the adsorptionof a selected surfactants. Thus, it was possible to freeze the liquid drops in a controlled anisotropicshapes. This phenomenon was correlated to a liquid-solid transition of the interface demonstrated byrheological measurements of the interfacial moduli. These were, moreover, quantitatively related tothe anisotropy of frozen droplets.