Thesis (Ph. D.)--Lehigh University, 1997. / Includes vita. Includes bibliographical references (leaves 230-239).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1985. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 426-438).

Braunschweig, Techn. Universiẗat, Diss., 1999.

Braunschweig, Techn. Universiẗat, Diss., 2000.

Braunschweig, Techn. Universiẗat, Diss., 2000.

Duisburg, Universiẗat, Diss., 2002.

Halle, Wittenberg, Universiẗat, Diss., 2002.

L'objectif de ce travail est d'étudier la separation d'une emulsion stable par des procédés de coalescence et de flottation. Une huile de coupe commerciale (Castrol Cooledge BI) a été utilisée pour synthétiser une eau résiduaire huileuse, car elle forme facilement une emulsion stable avec l'eau. Les expériences en coalesceurs ont été conduites sur un média en polypropylène de différentes formes, incluant des granules, des fibres et des tubes. Les effets de la vitesse d'écoulement de l'émulsion et de la hauteur du lit coalesceur ont été testés. Pour le procédé de flottation, les deux techniques de flottation à air dissout (DAF) et de flottation à air induit (IAF) à l'échelle pilote ont été employés pour la séparatiobn de l'émulsion avec addition de sulfate d'aluminium (Al2(SO4)3) comme coagulant. Les influences des conditions opératoires sur l'efficacité de séparation ont été examinées. L'émulsion préparée est très stable comme suggéré par la très petite taille des gouttes et leur potentiel zéta fortement négatif. Lémulsion a été partiellement séparée par le coalesceur, la plus grande efficacité atteint étant de 43% pour une hauteur de lit de 10cm de polypropylène tubulaire et une vitesse d'émulsion de 2cm/s. Dans le cas de la séparation par flottation, une efficacité de 85% a été obtenue par DAF et par IAF. Cependant, la séparation par flottation n'est pas du tout effective sans coagulation préalable. C'est pourquoi, la déstabilisation de l'émulsion d'huile de coupe par le sulfate d'aluminium a été plus précisément étudiée. Le principal mécanisme de déstabilisation est la flocculation par balayage qui intervient pour une concentration en ion Al3+ de 1.0mM et un pH entre 6.5 et 7.5, pour lesquels des flocs solides peuvent être observés. Pour de plus faibles doses de Al3+, la déstabilisation n'est pas efficace, suggérant que la coalescence seule des gouttes entre elles n'est pas suffisante pour effectuer la séparation. Les flocs ont été analysés en ce qui concerne leur composition chimique et leur structure cristalline, confirmant ainsi la formation d'hydroxyde d'aluminium (Al(OH)3) qui joue un rôle majeur dans la floculation par balayage. De plus, les résultats expérimentaux obtenus en flottatest correspondent à ceux obtenus à l'échelle pilote. L'addition de coagulant est nécessaire pour obtenir une séparation efficace. Cependant, il a aussi été montré que l'augmentation de la dose de Al3+ au-delà de 1.0mM n'entraine pas une augmentation de l'efficacité de séparation. Enfin, les interactions goutte-bulle et floc-bulle ont été observés dans une cellule de visualisation construites dans cet objectif. Aucune interaction entre bulle et gouttes d'huile n'est observée alors que les flocs s'attachent à la surface de la bulle, expliquant la différence observée entre la séparation de l'huile de coupe floculée par flottation et l'inefficacité du procédé en l'absence de flocs. / The objective of this work was to study the separation of the stable oily emulsion by coalescer and flotation processes. The commercial Castrol Cooledge BI cutting oil was applied for synthesizing the oily wastewater since it can easily form a stabilized emulsion with water. The coalescer experiments were conducted by using polypropylene media with different shapes including granule, fiber, and tube. Effects of emulsion flow velocity and bed height as well as the bed packing were considered. For the flotation, both the dissolved air flotation (DAF) and the induced air flotation (IAF) processes in the pilot scale were employed for the emulsion separation with the addition of aluminium sulfate (Al2(SO4)3) as a coagulant. Influences of operating conditions on the separation efficiency were investigated. The results indicated that the prepared emulsion was highly stable suggested by its small droplet sizes and high negative zeta potential. The emulsion was partly separated by the coalescer with the highest efficiency of 43% from the 10 cm bed of tubular polypropylene with 2 cm/s flow velocity. In the case of the separation by flotation, the highest efficiency of 85% can be achieved from both DAF and IAF. However, the separation by flotation was ineffective without the coagulation. Therefore, the destabilization of the cutting oil emulsion by aluminium sulfate was further investigated. The main destabilization mechanism was the sweep flocculation occurred at the Al3+ concentration of 1.0 mM and pH of 6.5 - 7.5, where solid flocs can be observed. At lower Al3+ dosage, the destabilization was inefficient suggesting that only droplet coalescence was insufficient for the separation. The flocs were analyzed for their chemical composition and crystalline structure to confirm the formation of aluminium hydroxide (Al(OH)3) that plays a role in the sweep flocculation. Furthermore, the results from the bench scale flotation carried out by the Flottatest were correspondent to those obtained from the pilot scale experiments. The addition of coagulant was needed for the effective separation. However, it was also found that the increase of Al3+ dosages further the 1.0 mM was unable to enhance the separation efficiency. Finally, the interactions of droplet-bubble and floc-bubble were observed in the special made observation cell. No interaction between oil droplets and a bubble can be seen contrasting with the case of oil flocs, which can attach on the bubble surface. This affirmed the difference between the separation of cutting oil emulsion by flotation with and without the formation of flocs.

No description available.

Aptamers are small DNA ligands that have been manually selected to strongly and specifically bind a target of interest. These molecules may prove superior to modern antibodies in a number of ways including price and reproducibility. One of the major advantages of using aptamers as opposed to antibodies is the relative speed of development. This, coupled with the repetitive nature of aptamer selection, means that the entire process is a possible target for automation. In the following experiments, a ssDNA aptamer is developed against the human red blood cell protein glycophorin A, partially through the novel use of a robotized benchtop. The process also utilizes an adapted protocol for emulsion PCR to further increase the efficiency of the selection process. After 11 rounds of selection, the DNA pools were sequenced leading to the generation of 14 potential aptamers. These aptamers were tested with the isolated protein and with human red blood cells resulting in several of the aptamers being deemed potential binders. Further work with these identified sequences could result in aptamers that can be reliably used to tag and delicately separate red blood cells from other cells of interest within blood, such as stem cells. The novel approaches to selection used in this work may also lead to quicker and more efficient generation of future aptamers.