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dc.contributor.advisorNunes, Suzana Pereira
dc.contributor.authorShi, Meixia
dc.date.accessioned2016-07-19T06:22:52Z
dc.date.available2017-07-19T00:00:00Z
dc.date.issued2016-06
dc.identifier.doi10.25781/KAUST-J7063
dc.identifier.urihttp://hdl.handle.net/10754/617211
dc.description.abstractWater scarcity is a serious global issue, due to the increasing population and developing economy, and membrane technology is an essential way to address this problem. Forward osmosis (FO) is an emerging membrane process, due to its low energy consumption (not considering the draw solute regeneration). A bottleneck to advance this technology is the design of the support layer for FO membranes to minimize the internal concentration polarization. In this dissertation, we focus on the structural study and modification of the support layer for FO membranes. Firstly, we digitally reconstruct different membrane morphologies in 3D and propose a method for predicting performance in ultrafiltration operations. Membranes with analogous morphologies are later used as substrate for FO membranes. Secondly, we experimentally apply substrates with different potentially suitable morphologies as an FO support layer. We investigate their FO performance after generating a selective polyamide layer on the top, by interfacial polymerization. Among the different substrates we include standard asymmetric porous membranes prepared from homopolymers, such as polysulfone. Additionally block copolymer membrane and Anodisc alumina membrane are chosen based on their exceptional structures, with cylindrical pores at least in part. 3D digitally reconstructed porous substrates, analogous to those investigated for ultrafiltration, are then used to model the performance in FO operation. Finally, we analyze the effect of intermediate layers between the porous substrate and the interfacial polymerized layer. We investigate two materials including chitosan and hydrogel. The main results are the following. Pore-scale modeling for digital membrane generation effectively predicts the velocity profile in different layers of the membrane and the performance in UF experiments. Flow simulations confirm the advantage of finger-like substrates over sponge-like ones, when high water permeance is sought. Cylindrical pores are advantageous for mass transfer. Block copolymer substrates have cylindrical pores in the top layer and very regular pore pattern at the surface. The Anodisc alumina membrane has cylindrical pores from top to bottom. Both substrates were experimentally tested for FO application successfully. A Darcy permeability higher than 1E-20 m2 for the intermediate layer would be necessary in order to facilitate the water flow.
dc.language.isoen
dc.subjectMembrane
dc.subjectMorphology
dc.subjectSimulation
dc.subjectForward Osmosis
dc.subjectSupport Layer
dc.titleStructural Study and Modification of Support Layer for Forward Osmosis Membranes
dc.typeDissertation
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.rights.embargodate2017-07-19
thesis.degree.grantorKing Abdullah University of Science and Technology
dc.contributor.committeememberCalo, Victor M.
dc.contributor.committeememberNg, Kim Choon
dc.contributor.committeememberSun, Shuyu
dc.contributor.committeememberWang, Yan
thesis.degree.disciplineEnvironmental Science and Engineering
thesis.degree.nameDoctor of Philosophy
dc.rights.accessrightsAt the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation became available to the public after the expiration of the embargo on 2017-07-19.
refterms.dateFOA2017-07-19T00:00:00Z


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