Thesis (Ph. D.)--University of Kentucky, 2001. / Title from document title page. Document formatted into pages; contains xiv, 254 p. : ill. Includes abstract. Includes bibliographical references (p. 237-253).

Berlin, Techn. Univ., Diss., 2001. / Computerdatei im Fernzugriff.

Berlin, Techn. Univ., Diss., 2001. / Computerdatei im Fernzugriff.

Th. État--Phys.--Paris 12, 1981.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: James M. Dickson. Includes bibliographical references (leaves 393-400). Also available online.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: James M. Dickson. Includes bibliographical references (leaves 393-400). Also available online.

No description available.

The production of zeolite membranes has developed over the last decade, and the membranes have been used extensively in pervaporation separation processes due to their resistance to chemical and thermal operating conditions. However, the conventional methods used in preparing anisotropic zeolite membranes, such as the secondary growth and in-situ crystallization methods, involve long and complex procedures that require the preparation of zeolite aluminosilicate gel prior to the fabrication process. Therefore, the aim of this study was to develop and test an easier, less expensive, and less time-consuming technique to fabricate different types of zeolite anisotropic membranes. Moreover, the fabrication of zeolite membranes using inexpensive kaolin raw materials taken straight out of the ground was taken into account and assessed. Within this framework, a novel technique of converting raw source alumina and silica, to a useful pure material of zeolite A was developed without any form of pre-treatment. Although this technique yielded a successful outcome in terms of the purity of the product, the later work conducted in fabricating membranes was focused on natural and commercial sources of zeolites rather than using the prepared products, to avoid the lengthy procedure. Anisotropic membranes of zeolite A, mordenite, and ZSM-5 were fabricated successfully using a simple, economical, and straight-forward technique. This technique made it possible to fabricate types of zeolite membranes that have been difficult to synthesise at the lab scale, where an anisotropic, clinoptilolite, thin membrane was fabricated for the first time in this study. All of the four membranes were subjected to different types of mixtures and provided promising results.

Pervaporation with a "reverse-selective" (hydrophobic) membrane is a promising technology for the energy-efficient separation of alcohols from dilute alcohol-water streams, such as those formed in the production of biofuels. Pervaporation depends on the selectivity and throughput of the membrane, which in turn is highly dependent on the membrane material. A nanocomposite approach to membrane design is desirable in order to combine the advantages and eliminate the individual limitations of previously-reported polymeric and zeolitic membranes. In this work, a hollow-fiber membrane composed of a thin layer of polymer/zeolite nanocomposite material on a porous polymeric hollow fiber support is developed. The hollow fiber geometry offers considerable advantages in membrane surface area per unit volume, allowing for easier scaling and higher throughput than flat-film membranes. Poly(dimethyl siloxane) (PDMS) and pure-silica MFI zeolite (silicalite-1) were investigated for these membranes. Iso-octane was used to dilute the dope solution to provide thinner coatings. Previously-spun non-selective Torlon hollow fibers were used as the support layer for the nanocomposite coatings. To determine an acceptable method for coating fibers with uniform, defect-free coatings, flat-film membranes (0 to 60 wt% MFI on a solvent-free basis) and hollow-fiber membranes (0 and 20 wt% MFI) were fabricated using different procedures. Pervaporation experiments were run for all membranes at 65C with a 5 wt% ethanol feed. The effects of membrane thickness, fiber pretreatment, coating method, zeolite loading, and zeolite surface treatment on membrane pervaporation performance were investigated.

Research project submitted in fulfillment of the academic requirements for the Masters Degree in Technology: Chemical Engineering, Durban University of Technology, 2010. / Globally there is renewed interest in the production of alternate fuels in the form of bioethanol and biodiesel. This is mainly due to the realization that crude oil stocks are limited hence the swing towards more renewable sources of energy. Bioethanol and biodiesel have received increasing attention as excellent alternative fuels and have virtually limitless potential for growth. One of the key processing challenges in the manufacturing of biofuels is the production of high purity products. As bioethanol is the part of biofuels, the main challenge facing bioethanol production is the separation of high purity ethanol. The separation of ethanol from water is difficult because of the existence of an azeotrope in the mixture. However, the separation of the ethanol/water azeotropic system could be achieved by the addition of a suitable solvent, which influences the activity coefficient, relative volatility, flux and the separation factor or by physical separation based on molecular size. In this study, two methods of high purity ethanol separation are investigated: extractive distillation and pervaporation. The objective of this project was to optimize and compare the performance of pervaporation and extraction distillation in order to produce high purity ethanol. The scopes of the investigation include:  Study of effect of various parameters (i) operating pressure, (ii) operating temperature, and (iii) feed composition on the separation of ethanol-water system using pervaporation.  Study the effect of using salt as a separating agent and the operating pressure in the extractive distillation process. The pervaporation unit using a composite flat sheet membrane (hydrophilic membrane) produced a high purity ethanol, and also achieved an increase in water flux with increasing pressure and feed temperature. The pervaporation unit facilitated separation beyond the ethanol – water system azeotropic point. It is concluded that varying the feed temperature and the operating pressure, the performance of the pervaporation membrane can be optimised. v The extractive distillation study using salt as an extractive agent was performed using the low pressure vapour-liquid equilibrium (LPVLE) still, which was developed by (Raal and Mühlbauer, 1998) and later modified by (Joseph et al. 2001). The VLE study indicated an increase in relative volatility with increase in salt concentration and increase in pressure operating pressure. Salt concentration at 0.2 g/ml and 0.3 g/ml showed complete elimination of the azeotrope in ethanol-water system. The experimental VLE data were regressed using the combined method and Gibbs excess energy models, particular Wilson and NRTL. Both models have shown the best fit for the ethanol/water system with average absolute deviation (AAD) below 0.005. The VLE data were subjected to consistency test and according to the Point test, were of high consistency with average absolute deviations between experimental and calculated vapour composition below 0.005. Both extractive distillation using salt as an extractive agent and pervaporation are potential technologies that could be utilized for the production of high purity ethanol in boiethanol-production.