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Article: Effects of chlorine exposure conditions on physiochemical properties and performance of a polyamide membrane-mechanisms and implications

TitleEffects of chlorine exposure conditions on physiochemical properties and performance of a polyamide membrane-mechanisms and implications
Authors
Issue Date2012
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/est
Citation
Environmental Science And Technology, 2012, v. 46 n. 24, p. 13184-13192 How to Cite?
AbstractUnderstanding the effects of chlorine exposure on polyamide (PA) based membranes is essential in membrane lifespan improvement. In this study, NF90 nanofiltration membrane was treated with sodium hypochlorite at different concentrations, pHs and durations. The changes in membrane elemental composition and bonding chemistry obtained from XPS and ATR-FTIR revealed the impacts of two competing mechanisms: N-chlorination and chlorination-promoted hydrolysis. More chlorine was incorporated into the PA matrix at pH <7, at which HOCl is dominant, while chlorine-promoted hydrolysis was more favorable at pH >7 with abundant hydroxyl groups. The membrane surface became more hydrophobic when chlorination was dominant, which in turn caused the water permeability of chlorinated membrane to decrease. Meanwhile, membrane became more hydrophilic and less cross-linked when hydrolysis effects were governing, which made the membrane more permeable for water. Rejection of charged solutes [NaCl, As(V)] improved in most chlorinating conditions due to increased charge density. However, when hydrolysis was severe (≥1000 ppm, pH 7 and 9), the enhanced charge repulsion effect could not compensate for the extensive amide bond cleavage, resulting in declined rejection. The lower rejection of neutral boric acid provided strong evidence of a less cross-linked separation layer. © 2012 American Chemical Society.
Persistent Identifierhttp://hdl.handle.net/10722/185437
ISSN
2015 Impact Factor: 5.393
2015 SCImago Journal Rankings: 2.664
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorDo, VTen_US
dc.contributor.authorTang, CYen_US
dc.contributor.authorReinhard, Men_US
dc.contributor.authorLeckie, JOen_US
dc.date.accessioned2013-07-30T07:32:31Z-
dc.date.available2013-07-30T07:32:31Z-
dc.date.issued2012en_US
dc.identifier.citationEnvironmental Science And Technology, 2012, v. 46 n. 24, p. 13184-13192en_US
dc.identifier.issn0013-936Xen_US
dc.identifier.urihttp://hdl.handle.net/10722/185437-
dc.description.abstractUnderstanding the effects of chlorine exposure on polyamide (PA) based membranes is essential in membrane lifespan improvement. In this study, NF90 nanofiltration membrane was treated with sodium hypochlorite at different concentrations, pHs and durations. The changes in membrane elemental composition and bonding chemistry obtained from XPS and ATR-FTIR revealed the impacts of two competing mechanisms: N-chlorination and chlorination-promoted hydrolysis. More chlorine was incorporated into the PA matrix at pH <7, at which HOCl is dominant, while chlorine-promoted hydrolysis was more favorable at pH >7 with abundant hydroxyl groups. The membrane surface became more hydrophobic when chlorination was dominant, which in turn caused the water permeability of chlorinated membrane to decrease. Meanwhile, membrane became more hydrophilic and less cross-linked when hydrolysis effects were governing, which made the membrane more permeable for water. Rejection of charged solutes [NaCl, As(V)] improved in most chlorinating conditions due to increased charge density. However, when hydrolysis was severe (≥1000 ppm, pH 7 and 9), the enhanced charge repulsion effect could not compensate for the extensive amide bond cleavage, resulting in declined rejection. The lower rejection of neutral boric acid provided strong evidence of a less cross-linked separation layer. © 2012 American Chemical Society.en_US
dc.languageengen_US
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/esten_US
dc.relation.ispartofEnvironmental Science and Technologyen_US
dc.subject.meshCalcium - Chemistryen_US
dc.subject.meshCationsen_US
dc.subject.meshChlorine - Chemistryen_US
dc.subject.meshFiltrationen_US
dc.subject.meshHalogenationen_US
dc.subject.meshHydrogen-Ion Concentrationen_US
dc.subject.meshHydrolysisen_US
dc.subject.meshMembranes, Artificialen_US
dc.subject.meshNanotechnologyen_US
dc.subject.meshNitrogen - Analysisen_US
dc.subject.meshNylons - Chemistryen_US
dc.subject.meshOxygen - Analysisen_US
dc.subject.meshPermeabilityen_US
dc.subject.meshPhysicochemical Phenomenaen_US
dc.subject.meshSodium Chloride - Chemistryen_US
dc.subject.meshSpectroscopy, Fourier Transform Infrareden_US
dc.subject.meshSurface Propertiesen_US
dc.subject.meshTime Factorsen_US
dc.subject.meshWater - Chemistryen_US
dc.subject.meshWater Pollutants, Chemical - Analysisen_US
dc.titleEffects of chlorine exposure conditions on physiochemical properties and performance of a polyamide membrane-mechanisms and implicationsen_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.doi10.1021/es302867fen_US
dc.identifier.pmid23214945-
dc.identifier.scopuseid_2-s2.0-84871285944en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-84871285944&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume46en_US
dc.identifier.issue24en_US
dc.identifier.spage13184en_US
dc.identifier.epage13192en_US
dc.identifier.isiWOS:000312432200021-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridDo, VT=54897725100en_US
dc.identifier.scopusauthoridTang, CY=35489259800en_US
dc.identifier.scopusauthoridReinhard, M=7102724330en_US
dc.identifier.scopusauthoridLeckie, JO=7006717360en_US

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