Jeon, Mi Young2018-07-262018-07-262016-05https://hdl.handle.net/11299/198387University of Minnesota Ph.D. dissertation. May 2016. Major: Chemical Engineering. Advisor: Michael Tsapatsis. 1 computer file (PDF); x, 139 pages.In separation processes, desirable products with high purity are acquired at the expense of high energy cost procedures such as distillation. Alternative separation processes, such as zeolite membrane separation and adsorption processes, are promising to reduce the energy cost of production since zeolites can discriminate molecules on the basis of size/shape and functionality. Indeed, the high cost of zeolite membranes can be reduced by fabricating thin membranes with high throughput. High aspect ratio zeolite nanosheets can be used to fabricate zeolite membranes with high throughput on porous supports. To date, however, there is no published evidence that scientists have successfully achieved nanosheet synthesis under the direct hydrothermal treatment route. This dissertation documents a successful direct hydrothermal synthesis of zeolite nanosheets via seeded-growth—a process that leads to zeolite membranes that exhibit high performance on xylene isomer and butane isomer permeation. To the best knowledge, this is the first achievement to prepare zeolite nanosheets without complicated post treatment such as exfoliation and purification process (density gradient centrifugation). Extensive parametric studies are conducted in order to establish the optimal synthesis condition for high quality zeolite nanosheets. Additionally, in an effort to understand the mechanism of nanosheet formation, the sequential evolution of seed crystals into zeolite nanosheets is observed by time-resolved TEM imaging analysis. Keeping in mind that in the future polymers could be used to reduce the costs of membrane manufacture, the de-templation of MFI nanosheets without formation of aggregates is discussed in this dissertation. In addition to membrane applications, this dissertation probes the roles of hydrophobicity in ethanol adsorption when hydrophobic siliceous zeolites, and defective siliceous zeolite nanosheets with house-of-card architecture are provided as adsorbents. Vapor phase ethanol adsorption and aqueous phase ethanol adsorption are compared to investigate how water molecules affect ethanol adsorption onto siliceous zeolites in the aqueous phase.enadsorptionmembranenanosheetszeoliteThesis or Dissertation