File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: Probing the nano- and micro-scales of reverse osmosis membranes-A comprehensive characterization of physiochemical properties of uncoated and coated membranes by XPS, TEM, ATR-FTIR, and streaming potential measurements

TitleProbing the nano- and micro-scales of reverse osmosis membranes-A comprehensive characterization of physiochemical properties of uncoated and coated membranes by XPS, TEM, ATR-FTIR, and streaming potential measurements
Authors
KeywordsCoating
Reverse Osmosis
Tem
Xps
Zeta Potential
Issue Date2007
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/memsci
Citation
Journal Of Membrane Science, 2007, v. 287 n. 1, p. 146-156 How to Cite?
AbstractThe performance of polyamide (PA) composite reverse osmosis (RO) membranes is essentially determined by a dense skin layer several hundred nanometers thick. Improved understanding of this critical thin layer will likely advance our understanding and control of membrane fouling and trace organics rejection. Unfortunately, the processes and exact chemistries for producing RO membranes are proprietary. In this study, XPS, ATR-FTIR, TEM microscopy, and streaming potential analysis were used to characterize commercial fully aromatic polyamide RO membranes. By using these techniques together in a systematic way, the presence of an aliphatic coating layer rich in -COH groups was confirmed for some commercial RO membranes. While the uncoated RO membranes had surface elemental compositions (measured by XPS) very close to the predicted values for polyamides based on the classical interfacial polymerization chemistry of trimesoyl chloride and 1,3-benzenediamine (m-phenylene-diamine), the coated membranes showed higher oxygen and lower nitrogen content. The typical layered structures (a polyamide layer on top of a polysulfone layer) and the rough ridge-and-valley features were clearly visible in TEM micrographs. For a coated membrane, a light-colored coating layer (lack of electron density) was visible, especially when a stained humic acid foulant layer was present to increase the contrast between the coating and the background. An intense OH stretching peak in conjunction with new aliphatic C-H stretching peaks were observed in ATR-FTIR spectra for coated membranes, where the aromatic {double bond, long}C-H stretching peak normally present for uncoated membranes was overwhelmed. High-resolution XPS scans on carbon 1s peaks confirmed the presence of alcoholic -COH groups in the coating layer, where an additional peak with a binding energy shift of 1.5 eV was identified in addition to the two peaks present for uncoated membranes: 284.6 eV (aliphatic and aromatic carbon atoms) and ∼287.8 eV (carboxylic and amide bond carbon atoms). The measured zeta potential values of the coated membranes were significantly less negative than those of the uncoated ones, suggesting that the coating layer is likely neutral. © 2006 Elsevier B.V. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/185374
ISSN
2015 Impact Factor: 5.557
2015 SCImago Journal Rankings: 2.042
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorTang, CYen_US
dc.contributor.authorKwon, YNen_US
dc.contributor.authorLeckie, JOen_US
dc.date.accessioned2013-07-30T07:32:02Z-
dc.date.available2013-07-30T07:32:02Z-
dc.date.issued2007en_US
dc.identifier.citationJournal Of Membrane Science, 2007, v. 287 n. 1, p. 146-156en_US
dc.identifier.issn0376-7388en_US
dc.identifier.urihttp://hdl.handle.net/10722/185374-
dc.description.abstractThe performance of polyamide (PA) composite reverse osmosis (RO) membranes is essentially determined by a dense skin layer several hundred nanometers thick. Improved understanding of this critical thin layer will likely advance our understanding and control of membrane fouling and trace organics rejection. Unfortunately, the processes and exact chemistries for producing RO membranes are proprietary. In this study, XPS, ATR-FTIR, TEM microscopy, and streaming potential analysis were used to characterize commercial fully aromatic polyamide RO membranes. By using these techniques together in a systematic way, the presence of an aliphatic coating layer rich in -COH groups was confirmed for some commercial RO membranes. While the uncoated RO membranes had surface elemental compositions (measured by XPS) very close to the predicted values for polyamides based on the classical interfacial polymerization chemistry of trimesoyl chloride and 1,3-benzenediamine (m-phenylene-diamine), the coated membranes showed higher oxygen and lower nitrogen content. The typical layered structures (a polyamide layer on top of a polysulfone layer) and the rough ridge-and-valley features were clearly visible in TEM micrographs. For a coated membrane, a light-colored coating layer (lack of electron density) was visible, especially when a stained humic acid foulant layer was present to increase the contrast between the coating and the background. An intense OH stretching peak in conjunction with new aliphatic C-H stretching peaks were observed in ATR-FTIR spectra for coated membranes, where the aromatic {double bond, long}C-H stretching peak normally present for uncoated membranes was overwhelmed. High-resolution XPS scans on carbon 1s peaks confirmed the presence of alcoholic -COH groups in the coating layer, where an additional peak with a binding energy shift of 1.5 eV was identified in addition to the two peaks present for uncoated membranes: 284.6 eV (aliphatic and aromatic carbon atoms) and ∼287.8 eV (carboxylic and amide bond carbon atoms). The measured zeta potential values of the coated membranes were significantly less negative than those of the uncoated ones, suggesting that the coating layer is likely neutral. © 2006 Elsevier B.V. All rights reserved.en_US
dc.languageengen_US
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/memscien_US
dc.relation.ispartofJournal of Membrane Scienceen_US
dc.subjectCoatingen_US
dc.subjectReverse Osmosisen_US
dc.subjectTemen_US
dc.subjectXpsen_US
dc.subjectZeta Potentialen_US
dc.titleProbing the nano- and micro-scales of reverse osmosis membranes-A comprehensive characterization of physiochemical properties of uncoated and coated membranes by XPS, TEM, ATR-FTIR, and streaming potential measurementsen_US
dc.typeArticleen_US
dc.identifier.emailTang, CY: tangc@hku.hken_US
dc.identifier.authorityTang, CY=rp01765en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1016/j.memsci.2006.10.038en_US
dc.identifier.scopuseid_2-s2.0-33845372829en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-33845372829&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume287en_US
dc.identifier.issue1en_US
dc.identifier.spage146en_US
dc.identifier.epage156en_US
dc.identifier.isiWOS:000243621700019-
dc.publisher.placeNetherlandsen_US
dc.identifier.scopusauthoridTang, CY=35489259800en_US
dc.identifier.scopusauthoridKwon, YN=14123466400en_US
dc.identifier.scopusauthoridLeckie, JO=7006717360en_US

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats