Novelthinfilmnanocompositemembranesincorporatedwit

NovelthinfilmnanocompositemembranesincorporatedwithfunctionalizedTiO2nanoparticlesfororganicsolventnanofiltrationMajidPeyravia,MohsenJahanshahia,AhmadRahimpoura,⇑,AliJavadib,SaeidehHajavibaMembraneResearchGroup,NanotechnologyResearchInstitute,SchoolofChemicalEngineering,BabolUniversityofTechnology,Babol,IranbFacultyofChemistry,KharazmiUniversity(formerTarbiatMoallemUniversity),Tehran,IranhighlightsNovelthinfilmnanocompositeSRNFmembraneswerefabricated.TiO2nanoparticleswerefunctionalizedbyamineandchlorideagents.FunctionalizedTiO2nanoparticleswereincorporatedatco-polyamidethinlayer.TheorganicsolventnanofiltrationofTiO2incorporatedSRNFmembraneswasstudied.articleinfoArticlehistory:Received1June2013Receivedinrevisedform20November2013Accepted6December2013Availableonline21December2013Keywords:TiO2modificationThinfilmcompositemembraneNanocompositemembraneSurfacepropertiesOrganicsolventabstractThepresentworkfocusesonthedevelopmentofthinfilmnanocomposite(TFN)nanofiltrationmem-branesbyformationofco-polyamidelayerassolventstablemembranes.Thethinlayerhasbeenelabo-ratedviainsituinterfacialincorporationofTiO2nanoparticlesalongwithfabricationofco-polyamidenetworkonapolyimide(PI)support.Inordertoimprovethecompatibilityofnanoparticlesinsidethepolymermatrix,bothamineandchloridecompoundswereemployedtofunctionalizeTiO2nanoparticles.Further,themechanismofTiO2surfacemodificationswaspresentedandprovedbyFTIRandEnergydis-persiveX-rayspectroscopy(EDAX)analyses.EDX-mappinganalysiswereusedinordertomorphologicalstudyofthemembranescontainTiO2nanoparticles.Theresultsshowedhighloadinganduniformdisper-sionofaminatedTiO2nanoparticlesthroughoutthehybridco-polyamidethinfilm.Asanunderstandingconcept,intermolecularcrosslinkingreactionsasagraphicalmodelwereproposedtoillustratethesta-bilityofthenanocompositemembranes.TransportpropertiesofthemembraneswereevaluatedbymethanolsolutionsoftwodifferentdyesandwereinterpretedbyDonnanStericPoreModel(DSPM).Interestingly,incomparisonwithTFCmembrane,TFNmembranesrepresentedhighermethanolfluxandgooddyerejectioninspiteoflowerswellingdegree.Moreover,thetypeofchemicalfunctions,TiO2loadingandthemembraneporesizewereconsideredasthecrucialeffectivefactorsonthemem-braneperformance.2013ElsevierB.V.Allrightsreserved.1.IntroductionThinfilmcomposite(TFC)membranespreparedviainterfacialpolymerization(IP)haveoftenbeenusedfornanofiltrationduetotheirsuperiorpermeationperformancewhichpossesstheabilitytofractionatesmallcompoundswithmolecularweights(MW)intherangeof200–1000Da[1–3].Althoughmostcommer-cialTFCnanofiltrationmembranesaresuitablefortreatingaqueousstreams,manypotentialapplicationsinthechemicalindustryinvolvemuchmoreaggressiveconditions[3,4].Advancesindevelopmentofstablemembranesandtheirperformancechar-acterizationintheseharshapplicationswillthereforeexpandtheapplicationwindowofsuchmembranesincommercialprocesses.TFCnanofiltrationmembranesconsistofatleasttwolayerswithdifferentmaterialsinwhichapolymericthinfilmisformedasaselectivelayeruponaporoussub-layer,whichusuallyisanultrafiltrationmembraneandservesassupport[5–8].Severalpro-ceduressuchasinterfacialpolymerization[9],dipcoating[10]andplasmapolymerization[11]maybeusedtocoatasthecompositemembranes.Incasewherenanofiltrationoccurredinorganicmedia,eachlayerofthecompositemembraneischemicallystableinawiderangeoforganicsolvents,theseparatinglayerofmanyofthemembranesswellsappreciablyinmanysolventsresultingindiminishedselectivitythroughconvectivetransportacrossthemembrane[12].Inaddition,differentialswellinginthelayers1385-8947/$-seefrontmatter2013ElsevierB.V.Allrightsreserved.⇑Correspondingauthor.Address:BabolUniversityofTechnology,P.O.BOX484,Babol,Iran.Tel./fax:[phone].E-mailaddresses:[e-mail],[e-mail](A.Rahimpour).ChemicalEngineeringJournal241(2014)155–166ContentslistsavailableatScienceDirectChemicalEngineeringJournaljournalhomepage:[13].Nowadays,thereareseveralpolymersexhibitingsatisfactorychemicalresistanceusedformembranesupportviaphaseinversionprocess[14].Themajorchallengeissueisstillexistedonthedevelopmentofthinlayeratthedestructionconditions.Generally,theincreaseofthinlayersta-bilitycausestoimprovethemembraneperformance.Whereasatthediffusivity-basedmembraneseparation,organicsolventspref-erentiallypermeateacrossthemembrane,theswellingeffectsofthintoplayeraremorepossible.JimenezSolomonandetal.werereportednewgenerationoforganicsolventnanofiltrationthathavethepotentialtoachievehigherfluxesthanintegrallyskinnedasymmetricOSNmembranes,withoutsacrificingselectivity.Thesehighfluxthinfilmcomposite(TFC)membraneswerepreparedviainterfacialpolymerizationofaminemonomersandacylchloridecross-linker[9,15].Recently,nanocompositesmembraneshaveshowngreatpromiseaspossiblemembranematerialsfororganicsolventseparations[16–18].Incorporationofnanoparticleswithinthin-filmlayerforseparationsbetweenmoleculesinorganic–organicsystemsisap