Foam fractionation is an economical and environmentally friendly separation method for surface active material using a rising column of foam. The system of foam fractionation column with reflux is selected since such a system can improve the enrichment of the product collected from the top of the column. Due to the reflux, it is assumed that there is more surface active material (surfactant and/or protein) in the Plateau border than that in the foam lamella, so that the Plateau border acts as a surfactant/protein reservoir. The aim of this thesis is to investigate the adsorption and transport of surface active material such as surfactant and/or protein onto the surface of a lamella in a foam fractionation column with reflux using mathematical simulation. There are two steps involved in adsorption of surface active material onto a bubble surface within foam, which are diffusion from the bulk solution into the subsurface, a layer next to the interface, followed by adsorption of that material from the subsurface onto the interface. The diffusion follows the Fick's second law, while the adsorption may follow the Henry, Langmuir or Frumkin isotherms, depending on the properties of the surface active material. The adsorption of mixed protein-surfactant follows the Frumkin isotherm. When there is a competition between protein and surfactant, the protein arrives onto the interface at a later time due to a slower diffusion rate and it displaces the surfactant molecules already on the surface since protein has a higher affinity for that surface than surfactant. The surfactant transport from a Plateau border onto a foam lamella is determined by the interaction of forces applied on the lamella surface, such as film drainage, due to the pressure gradient between the lamella and the Plateau border, the Marangoni effect, due to the gradient of surface tension, and surface viscosity, as a reaction to surface motion. In this thesis, there are two different models of film drainage. One approach uses assumption of a film with a mobile interface and the other model assumes a film with a rigid interface. In the absence of surface viscosity, the Marangoni effect dominates the film drainage resulting in accumulation of surfactant on the surface of the foam lamella in the case of a lamella with a rigid interface. In the case of a film with a mobile interface, the film drainage dominates the Marangoni effect and surfactant is washed away from the surface of the lamella. When the drainage is very fast, such as that which is achieved by a film with a mobile interface, the film could be predicted to attain the thickness of a common black film, well within the residence time in a foam fractionation column, at which point the film stops draining and surfactant starts to accumulate on the lamella surface. The desirable condition in operation of a foam fractionation column however is when the Marangoni effect dominates the film drainage and surfactant accumulates on the surface of a foam lamella such as the one achieved by a film with a rigid interface. In the presence of surface viscosity and the absence of film drainage, the surface viscous forces oppose the Marangoni effect and reduce the amount of surfactant transport onto the foam lamella. A larger surface viscosity results in less surfactant transport onto the foam lamella. In addition, the characteristic time scale required for surfactant transport is shorter with a shorter film length.

Doctoral thesis is focused on the study, research and development of heat insulating moulded refractory materials. The replacement of shaped instead of unshaped refractories is recently and strongly industrially demanded and belongs to ongoing research topics. With the increasing demand of energy savings, the excellent insulation properties are essential. The insulating properties of castables are the result of targeted porosity formation. The porosity is coming from the controlled air intrusion into material resulted to foamed structure. The foaming process was achieved by mixing of separately prepared aqueous foam into raw castable slurry or by in situ foaming of intensively mixed castable slurry with the surfactant additive. Nevertheless, the study of foam behaviour and the influence of additives on binder hydration and setting processes (i.e. calciumaluminate cement) was substantial for successful preparation of the experimental samples. The two types of the experimental samples were prepared. The first one was based on mixing of kaolin slurry with pre-prepared aqueous foam, whereas the de-aglomeration ability of kaolin specie was utilized to water-particle film formation. In situ foaming of multicomponent system is the second one. The both processes brought some negative attributes, so the optimal properties of prepared castables were achieved by their combination.

Les zones sources formées par les organochlorés dans les sols (DNAPL) peuvent contaminer les aquifères pour plusieurs siècles en alimentant un panache de composés dissous. Pour épuiser ces zones sources, pomper le DNAPL est la solution la plus simple, mais l’efficacité est limitée par le cheminement préférentiel de l'eau dans le sol et les forces capillaires qui piègent le DNAPL. Les stratégies plus agressives (dissolution, traitement thermique, dégradation chimique…) sont aussi plus coûteuses. Dans cette thèse, deux stratégies de traitement à base de mousse de surfactant ont été développées et évaluées au laboratoire en préparation d’un essai terrain. La première stratégie utilise l’injection de mousse en zone source pour mobiliser de façon contrôlée le DNAPL et le diriger vers des puits de pompage. Dans les meilleures conditions, la saturation en DNAPL après traitement a pu être abaissé en dessous de 1 % avec une consommation de surfactant inférieure à 10 g kg-1 de DNAPL éliminé. La seconde stratégie utilise la mousse comme vecteur de réactif (hydrogène) pour accélérer la biodégradation des composés dissous dans le panache. Sous forme de mousse, l’hydrogène a été délivré de façon ciblée et plus rémanente dans l’horizon à traiter. Les technologies développées se sont montrées très prometteuses à l’échelle du terrain et lors de l’évaluation technico-économique. De la recherche reste nécessaire pour rendre ces procédés plus prédictibles lors de leur mise en œuvre. / Source zones formed by chlorinated organic compounds in soils (DNAPL) can contaminate aquifers for several centuries by feeding a plume of dissolved compounds. To deplete those source zones, DNAPL pumping is the simplest option, but the efficacy is limited by preferential water flow in the soil and capillary forces that are trapping the DNAPL. More aggressive strategies (dissolution, thermal treatment, chemical degradation...) are also costlier. Within this thesis work, two treatment strategies using surfactant foam were developed and assessed at lab-scale to prepare field assessment. The first strategy relies on foam injection in the source zone to mobilize the DNAPL in a controlled fashion to drive it ahead to pumping wells. In the best conditions, DNAPL saturation was lowered below 1% after treatment with a surfactant consumption below 10 g kg-1 of DNAPL removed. The second strategy uses foam as a reagent (hydrogen) carrier to accelerate the biodegradation of dissolved compounds in the plume. When injected as a foam, hydrogen was delivered in a targeted and more persistent manner in the strata to be treated. Developed technologies showed to be promising at field-scale and when the technico-economic assessment was conducted. Research still remains to be done to make those techniques more predictable during their implementation.