Title:
Development of next generation mixed matrix hollow fiber membranes for butane isomer separation

dc.contributor.advisor Koros, William J.
dc.contributor.author Liu, Junqiang en_US
dc.contributor.committeeMember Meredith, Carson J.
dc.contributor.committeeMember Jones, Christopher W.
dc.contributor.committeeMember Ronald R. Chance
dc.contributor.committeeMember Sankar Nair
dc.contributor.committeeMember Victor Breedveld
dc.contributor.department Chemical Engineering en_US
dc.date.accessioned 2012-02-17T19:20:29Z
dc.date.available 2012-02-17T19:20:29Z
dc.date.issued 2010-10-13 en_US
dc.description.abstract Mixed matrix hollow fiber membranes maintain the ease of processing polymers while enhancing the separation performance of the pure polymer due to inclusion of molecular sieve filler particles. This work shows the development process of high loading mixed matrix hollow fiber membranes for butane isomer separation, from material selection and engineering of polymer-sieve interfacial adhesion to mixed matrix hollow fiber spinning. The matching of gas transport properties in polymer and zeolite is critical for forming successful mixed matrix membranes. The nC4 permeability in glassy commercial polymers such as Ultem® and Matrimid® is too low (< 0.1 Barrer) for commercial application. A group of fluorinated (6FDA) polyimides, with high nC4 permeability and nC4/iC4 selectivity, are selected as the polymer matrix. No glassy polymers can possibly match the high permeable MFI to make mixed matrix membranes with selectivity enhancement for C4s separation. Zeolite 5A, which has a nC4 permeability (~3 Barrer) and nC4/iC4 selectivity (essentially ∞), matches well with the 6FDA polymers. A 24% nC4/iC4 selectivity enhancement was achieved in mixed matrix membranes containing 6FDA-DAM and 25 wt% treated 5A particles. A more promising mixed matrix membrane contains 6FDA-DAM-DABA matrix and 5A, because of a better match of gas transport properties in polymer and zeolite. Dual layer hollow fibers, with cellulose acetate core layer and sheath layers of 6FDA polyimides, were successfully fabricated. Successive engineering of the 6FDA sheath layer and the dense skin is needed for the challenging C4s separation, which is extremely sensitive to the integrity of the dense skin layer. The delamination-free, macrovoid-free dual layer hollow fiber membranes provide the solution for the expensive 6FDA polyimides spinning. Mixed matrix hollow fiber membranes are spun base on the platform of 6FDA/Cellulose acetate dual layer hollow fibers. Preliminary results suggest that high loading mixed matrix hollow fiber membranes for C4s is feasible. Following research is needed on the fiber spinning with well treated zeolite 5A nanoparticles. The key aspect of this research is elucidating the three-step (sol-gel-precipitation) mechanism of sol-gel-Grignard treatment, based on which further controlling of Mg(OH)2 whisker morphologies is possible. A Mg(OH)2 nucleation process promoted by acid species is proposed to explain the heterogeneous Mg(OH)2 growing process. Different acid species were tried: 1) HCl solution, 2) AlClx species generated by dealumination process and 3) AlCl3 supported on zeolite surfaces. Acids introduced through HCl solution and dealumination are effective on commercial 5A particles to generate Mg(OH)2 whiskers in the sol-gel-Grignard treatment. Supported AlCl3 is effective on both commercial and synthesized 5A particles (150 nm-1 µm) during the sol-gel-Grignard treatment, in terms of promoting heterogeneous Mg(OH)2 whiskers formation. But the byproduct of Al(OH)3 layer separates the Mg(OH)2 whiskers from zeolite surface, and leads to undesirable morphologies for polymer-zeolite interfacial adhesion. The elucidation of sol-gel-Grignard mechanism and importance of zeolite surface acidity on Mg(OH)2 formation, builds a solid foundation for future development towards ''universal'' method of growing Mg(OH)2 whiskers on zeolite surfaces. en_US
dc.description.degree PhD en_US
dc.identifier.uri http://hdl.handle.net/1853/42807
dc.publisher Georgia Institute of Technology en_US
dc.subject Butane isomer separation en_US
dc.subject Mixed matrix membrane en_US
dc.subject Hollow fiber membrane en_US
dc.subject Membrane separation en_US
dc.subject.lcsh Gas separation membranes en_US
dc.subject.lcsh Gases Separation en_US
dc.subject.lcsh Separation (Technology) en_US
dc.subject.lcsh Membranes (Technology) en_US
dc.subject.lcsh Zeolites en_US
dc.subject.lcsh Polymers en_US
dc.title Development of next generation mixed matrix hollow fiber membranes for butane isomer separation en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Koros, William J.
local.contributor.corporatename School of Chemical and Biomolecular Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 0059291f-6b5a-4a6c-a661-eef665ac3a18
relation.isOrgUnitOfPublication 6cfa2dc6-c5bf-4f6b-99a2-57105d8f7a6f
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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