3D visualization of the internal nanostructure of polyamide thin films in RO membranes

Handle URI:
http://hdl.handle.net/10754/581796
Title:
3D visualization of the internal nanostructure of polyamide thin films in RO membranes
Authors:
Pacheco Oreamuno, Federico ( 0000-0002-7030-4689 ) ; Sougrat, Rachid; Reinhard, Martin; Leckie, James O.; Pinnau, Ingo ( 0000-0003-3040-9088 )
Abstract:
The front and back surfaces of fully aromatic polyamide thin films isolated from reverse osmosis (RO) membranes were characterized by TEM, SEM and AFM. The front surfaces were relatively rough showing polyamide protuberances of different sizes and shapes; the back surfaces were all consistently smoother with very similar granular textures formed by polyamide nodules of 20–50 nm. Occasional pore openings of approximately the same size as the nodules were observed on the back surfaces. Because traditional microscopic imaging techniques provide limited information about the internal morphology of the thin films, TEM tomography was used to create detailed 3D visualizations that allowed the examination of any section of the thin film volume. These tomograms confirmed the existence of numerous voids within the thin films and revealed structural characteristics that support the water permeance difference between brackish water (BWRO) and seawater (SWRO) RO membranes. Consistent with a higher water permeance, the thin film of the BWRO membrane ESPA3 contained relatively more voids and thinner sections of polyamide than the SWRO membrane SWC3. According to the tomograms, most voids originate near the back surface and many extend all the way to the front surface shaping the polyamide protuberances. Although it is possible for the internal voids to be connected to the outside through the pore openings on the back surface, it was verified that some of these voids comprise nanobubbles that are completely encapsulated by polyamide. TEM tomography is a powerful technique for investigating the internal nanostructure of polyamide thin films. A comprehensive knowledge of the nanostructural distribution of voids and polyamide sections within the thin film may lead to a better understanding of mass transport and rejection mechanisms in RO membranes.
KAUST Department:
Advanced Membranes and Porous Materials Research Center; Physical Sciences and Engineering (PSE) Division; Imaging and Characterization Core Lab
Citation:
3D visualization of the internal nanostructure of polyamide thin films in RO membranes 2015 Journal of Membrane Science
Publisher:
Elsevier BV
Journal:
Journal of Membrane Science
Issue Date:
2-Nov-2015
DOI:
10.1016/j.memsci.2015.10.061
Type:
Article
ISSN:
03767388
Additional Links:
http://linkinghub.elsevier.com/retrieve/pii/S037673881530291X
Appears in Collections:
Articles; Advanced Membranes and Porous Materials Research Center; Advanced Nanofabrication, Imaging and Characterization Core Lab; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorPacheco Oreamuno, Federicoen
dc.contributor.authorSougrat, Rachiden
dc.contributor.authorReinhard, Martinen
dc.contributor.authorLeckie, James O.en
dc.contributor.authorPinnau, Ingoen
dc.date.accessioned2015-11-05T08:53:43Zen
dc.date.available2015-11-05T08:53:43Zen
dc.date.issued2015-11-02en
dc.identifier.citation3D visualization of the internal nanostructure of polyamide thin films in RO membranes 2015 Journal of Membrane Scienceen
dc.identifier.issn03767388en
dc.identifier.doi10.1016/j.memsci.2015.10.061en
dc.identifier.urihttp://hdl.handle.net/10754/581796en
dc.description.abstractThe front and back surfaces of fully aromatic polyamide thin films isolated from reverse osmosis (RO) membranes were characterized by TEM, SEM and AFM. The front surfaces were relatively rough showing polyamide protuberances of different sizes and shapes; the back surfaces were all consistently smoother with very similar granular textures formed by polyamide nodules of 20–50 nm. Occasional pore openings of approximately the same size as the nodules were observed on the back surfaces. Because traditional microscopic imaging techniques provide limited information about the internal morphology of the thin films, TEM tomography was used to create detailed 3D visualizations that allowed the examination of any section of the thin film volume. These tomograms confirmed the existence of numerous voids within the thin films and revealed structural characteristics that support the water permeance difference between brackish water (BWRO) and seawater (SWRO) RO membranes. Consistent with a higher water permeance, the thin film of the BWRO membrane ESPA3 contained relatively more voids and thinner sections of polyamide than the SWRO membrane SWC3. According to the tomograms, most voids originate near the back surface and many extend all the way to the front surface shaping the polyamide protuberances. Although it is possible for the internal voids to be connected to the outside through the pore openings on the back surface, it was verified that some of these voids comprise nanobubbles that are completely encapsulated by polyamide. TEM tomography is a powerful technique for investigating the internal nanostructure of polyamide thin films. A comprehensive knowledge of the nanostructural distribution of voids and polyamide sections within the thin film may lead to a better understanding of mass transport and rejection mechanisms in RO membranes.en
dc.language.isoenen
dc.publisherElsevier BVen
dc.relation.urlhttp://linkinghub.elsevier.com/retrieve/pii/S037673881530291Xen
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in Journal of Membrane Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Membrane Science, 2 November 2015. DOI: 10.1016/j.memsci.2015.10.061en
dc.subjectTEMen
dc.subjectTomographyen
dc.subjectPolyamide thin filmen
dc.subjectPolyamide nanostructureen
dc.subjectVoidsen
dc.title3D visualization of the internal nanostructure of polyamide thin films in RO membranesen
dc.typeArticleen
dc.contributor.departmentAdvanced Membranes and Porous Materials Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentImaging and Characterization Core Laben
dc.identifier.journalJournal of Membrane Scienceen
dc.eprint.versionPost-printen
dc.contributor.institutionDepartment of Civil and Environmental Engineering, Stanford University, Jerry Yang & Akiko Yamazaki Environment & Energy Building, 473 Via Ortega, Stanford, CA 94305-4020, United Statesen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorPacheco Oreamuno, Federicoen
kaust.authorSougrat, Rachiden
kaust.authorPinnau, Ingoen
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