一膜技術(shù)基礎(chǔ)課件

黃征青湖北工業(yè)大學(xué)化學(xué)與環(huán)境工程學(xué)院BasicPrinciplesofMembraneTechnologySecondeditionMarcelMulder膜技術(shù)基本原理ContentsChapter1：IntroductionChapter3：Preparationofsyntheticmembanes

Chapter4：CharacterazitionofmembranesChapter6：MembraneprocessesandtheirapplicationChapter7：Polarizationphenomenaandmembranefouling主要參考書1.

時鈞，袁權(quán)，高從階主編，膜技術(shù)手冊，化學(xué)工業(yè)出版社2.

朱長樂，劉茉娥，朱才全，“化學(xué)工程手冊”第18篇，“薄膜過程”，北京，化學(xué)

工業(yè)出版社，19873.

王湛編，膜分離技術(shù)基礎(chǔ)，北京，化學(xué)工業(yè)出版社，20004.

劉茉娥等編著，膜分離技術(shù)，化學(xué)工業(yè)出版社，20005.

劉茉娥等編著，膜技術(shù)應(yīng)用手冊，化學(xué)工業(yè)出版社，20016.

李基森，許景文，徐元耀等。離子交換膜及其應(yīng)用，北京：科學(xué)出版社，19777.

王振坤編，離子交換膜一制備，性能及應(yīng)用，北京：化學(xué)工業(yè)出版社，19858.

張維潤等著，電滲析工程學(xué)，北京：科學(xué)出版社，19959.

李琳譯，膜技術(shù)基本原理（第二版），北京：清華大學(xué)出版社，199910.高以垣，葉凌碧，膜分離技術(shù)基礎(chǔ)，1989，北京：科學(xué)出版社主要刊物膜科學(xué)與膜技術(shù)水處理技術(shù)JournalmembraneSci；JMembBio,Desalination高分子類：

Polymer,Polymerint,JApplPoly,JPolySci,Macromolecules電化學(xué)類

：JApplElectrochem,JElectroAnaChem分離工程類：

SepSciTec,SepPurimethod/Technology環(huán)境、界面、食品IIntroductionHowdoyougetapurecomponentfromamixture?Canthisprocesshappenspontaneously?1.1.AnalysisofthermodynamicsCHHHCHCHCCCCCCCHHHHHH(a)(b)Whatmethodscanyouusetogetapurecomponentfromamixture?

Distillation,evaporation,蒸餾，蒸發(fā)Crystallisation結(jié)晶Extraction萃取Assimilation吸收Centrifugation離心Filtration過濾Dryness干燥Adsorption吸附affinitychromatography親和色譜1.2.Generalcriteriaforthechooseofaseparationprocess

Twogeneralcriteriaapplytoallseparationprocesses:1).Theseparationmustbefeasibletechnically(becapableofaccomplishingthedesiredseparationandachieveaqualityproduct);2).Theseparationmustbefeasibleeconomically.1.3.TheobjectivesofseparationConcentration濃縮:thedesiredcomponentispresentinalowconcentrationandsolventhastoberemoved.Purification純化:undesirableimpuritieshavetoberemoved.purification:undesirableimpuritieshavetoberemoved.Fractionation分級:amixturemustbeseparatedintotwoormoredesiredcomponents.Reactionmediation反應(yīng)調(diào)節(jié):combinationofachemicalorbiochemicalreactionwithacontinuousremovedofproductswillincreasethereactionrate.Fig.I.2Schematicrepresentationofamembraneprocesswherethefeedstreamhasbeenseparatedintoaretentateandapermeatestream.feedretentatepermeatemodule進(jìn)料液截留液滲透液膜組件Thefollowingdrawbacksshouldbementioned:-Concentrationpolarization濃差極化/membranefouling膜污染;-Lowmembranelifetime;-Lowselectivity選擇性orflux通量;-Up-scalingfactorismoreorlesslinear.2.Introductiontomembraneprocesses2.1.Introduction2.2.Theparametersofmembraneperformance（膜性能參數(shù)）feedPhase1membranePhase2permeateDrivingforce△C,△P,△T,△EFig.I.3Schematicrepresentationofatwo-phasesystemseparatedbyamembrane物質(zhì)透過膜的主要三種方式：被動傳遞促進(jìn)傳遞主動傳遞◆

被動傳遞：物質(zhì)由高化學(xué)位相向低化學(xué)位相傳遞，這一化學(xué)位的差就是膜分離過程的推動力。壓力差濃度差電位差溫度差推動力AAμ‘Aμ‘’Aμ‘A>μ‘’A被動傳遞◆促進(jìn)傳遞：膜內(nèi)有載體，在高化學(xué)位一側(cè)，載體同被傳遞的物質(zhì)發(fā)生反應(yīng)，而在低化學(xué)位一側(cè)又將被傳遞的物質(zhì)釋放，這種傳遞過程有很高的選擇性。μ‘A>μ‘’AA+B→ABAAB→A+BAμ‘Aμ‘’A促進(jìn)傳遞BAB◆

主動傳遞：膜中的載體同被傳遞物質(zhì)在低化學(xué)位側(cè)發(fā)生反應(yīng)并釋放能量，使被傳遞物質(zhì)由低化學(xué)位一側(cè)被傳遞到高化學(xué)位一側(cè)，物質(zhì)的傳遞方向為逆化學(xué)位梯度方向。μ‘A<μ‘’AA+B→ABAAB→A+BAμ‘Aμ‘’A化學(xué)反應(yīng)主動傳遞BAB2.2.TheparametersofmembraneperformanceFlow流量(oftendenotedastheflux通量orpermeationrate滲透速率):Flowisdefinedasthevolumeflowingthroughthemembraneperunitsareaandtime.Volumefluxmaybereadilyconvertedtomassfluxormolefluxbyusingthedensityandmolecularweight.（單位推動力下）物質(zhì)在單位時間內(nèi)透過單位面積膜的量。Inordertocomparegasfluxeswitheachotherthevolumeisalwaysgivenunderstandardconditions(STP)whichisat0℃and1atmosphere(=1.0013bar).JVA*t=Selectivity

選擇性：不同物質(zhì)在兩相中的濃度變化比Theselectivityofamembranetowardsamixtureisgenerallyexpressedbyoneoftwoparameters:theretention(R)ortheseparationfactor(α).Membraneselectivitytowardsgasmixturesandmixturesoforganicliquidsisusuallyexpressedintermsoftheseparationfactorα.ForamixtureconsistingofcomponentsAandBtheselectivityfactorαA/Bisgivenby

αA/B=(yA/yB)/(xA/xB)WhereyAandyBaretheconcentrationsofcomponentsAandBinthepermeateandxAandxBaretheconcentrationsofcomponentsAandBinthefeed.Theselectivityischoseninsuchawaythatitsvalueisgreaterthanunity.ThenifthepermeationrateofcomponentAthroughthemembraneislargerthanthatofcomponentB,theseparationfactorisdenotedasαA/B;ifcomponentBpermeatespreferentially,thentheseparationfactorisgivenbyαB/A.

3.ThehistoryofmembranetechnologyEventowardsthemiddleofeighteenthcenturymembranephenomenawereobservedandstudied,primarilytoelucidatethebarrierpropertiesandrelatedphenomenaratherthantodevelopmembranesfortechnicalandindustrialapplications.

TableI.2Developmentof(technical)membraneprocessesmembraneprocesscountryyearapplicationmicrofiltrtion+Germany1920laboratoryuse(bacteriafilter)ultrafiltration+Germany1930laboratoryusehemodialysis+Netherlands1950artificialkidneyelectrodialysis*USA1955desalinationreverseosmosis*USA1960seawaterdesalinationultrafiltration*USA1960concentrationofmacromolecuesgasseparation*USA1979hydrogenrecoverymembranedistillation+Germany1981concentrationofaqueoussolutionspervaporation*Germany/Netherlands1982dehydrationoforganicsolvent+smallscale*industrialscaleAbreakthroughforthemembranepreparationwasthedevelopmentofasymmetricmembranes(LoebandSourirajan).Thesemembranesconsistofaverythindensetoplayer(thickness<0.5μm)supportedbyaporoussublayer(thickness50-200μm).Thetoplayerorskindeterminesthetransportratewhiletheporoussublayeronlyactsasasurport.Thepermeationrateisinverselyproportionaltothethicknessoftheactualbarrierlayerandthusasymmetricmembranesshowamuchhigherpermeationratethan(homogeneous)symmetricmembranesofacomparablethickness(RO).AnotherbreakthroughwasfromtheworkofHenisandTripodi.Theyplacedaverythinhomogenouslayerofapolymerwithhighgaspermeabilityontopofanasymmetricmembrane,ensuringthattheporesintoplayerwerefilledandthataleak-freecompositemembranesuitableforgasseparation4.DefinitionandClassificationofamembrane4.1.DefinitionofamembraneAlthoughitisdifficulttogiveanexactdefinitionofamembrane,ageneraldefinitioncouldbe:Aselectivebarrierbetweentwophases,theterm‘selective’beinginherenttomembraneoramembraneprocess.4.2.

ClassificationToobtainamoreinformativeunderstanding,membranescanbeclassifiedaccordingtodifferentviewpoints.Thefirstclassificationisbynature,i.e.biologicalorsyntheticmembrane,thisistheclearestdistinctionpossible.Anothermeansofclassifyingmembranesisbymorphologyorstructure.SolidmembraneNon-livingmembraneLiquidmembraneEmulsionliquidmembraneSupportedliquidmembraneOrganicmembraneInorganicmembraneBiologicalmembranesSyntheticmembranesMembranesLivingmembraneMembranesNonporousmembraneCylindricalPorousmembanePorousmembraneL-SmembraneCompositemembraneSymmetric(isotropic)membranesAsymmetric(Anisotropic)membranes5.Membraneprocesses5.1MembraneprocessesanddrivingforcesInmanycasesthepermeationratethroughthemembraneisproportionaltothedrivingforces,i.e.theflux-forcerelationshipcanbedescribedbyalinearphenomenologicalequation.Proportionalitybetweentheflux(J)andthedrivingforceisgivenbyJ=-AdX/dxWhereAiscalledthephenomenologicalcoefficientand(dX/dx)isthedrivingforce,expressedasthegradientofX(temperature,concentration,pressure)alongacoordinatexperpendiculartothetransportbarrier.Phenomenologicalequationscanbeusedtodescribemassflux,heatflux,volumeflux,momentumfluxandelectricalflux.TableI.4PhenomenologicalequationsmassfluxJm=-Ddc/dx(Fick)D(thediffusioncoeffient)volumefluxJv=-LpdP/dx(Darcy)Lp(permeabilitycoeffient)heatfluxJh=-λdT/dx(Fourier)λ(thermaldiffusivity)momentumfluxJn=-υdv/dx(Newton)υ(=η/ρkinematicviscosity)electricalfluxJi=-l/RdE/dx(Ohm)l/R(electricalconductivity)

LLLGGGDrivingforcePhase

1Phase2membraneFig.I.7Schematicrepresentationofphase

divided

by

amembraneForapurecomponentpermeatingthroughamembrane,itispossibletoemploylinearrelationstodescribetransport.However,whentwoormorecomponentspermeatesimultaneously,suchrelationscannotbegenerallyemployedsincecouplingphenomenamayoccurinthefluxesandforces.Thesecouplingphenomenacanbedescribedintermsoftheformalismofnon-equilibriumthermodynamics.TableI.4Somemembraneprocessesanddrivingforcesmembraneprocessphase1phase2drivingforcemicrofiltration(微濾)LLΔPultrafiltration(超濾)LLΔPnanofiltration(納濾)LLΔPreverseosmosis(反滲透)LLΔPpiezodialysis(加壓滲析)LLΔPgasseparation(氣體分離)GGΔPvaporpermeation(蒸發(fā)滲透)GGΔPpervaporation(滲透蒸發(fā))LGΔPelectrodialysis(電滲析)LLΔEmembraneelectrolysis(膜電解)LLΔEdialysis(滲析或透析))LLΔcdiffusiondialysis(擴(kuò)散滲析)LLΔcmembranecontactors(膜接觸器)LLΔcGLΔc/ΔPLGΔc/ΔPthermo-osmosis(熱滲透)LLΔT/ΔPmembranedistillation(膜蒸餾)LLΔT/ΔP5.2.Applicationrangeofvarious

membraneprocessesumARELATIVESIZEOFCOMMONMATERIAL過濾對象MOLECULARWEIGHT分子量0.001100.011000.110001.01041010510010001061071002005,00020,000150,000500,000Aqueoussalts水中鹽份Metalions金屬離子Sugars蔗糖FILTRATIONTECHNO-LOGY過濾方法Pyrogens熱源Virus病毒Colloidalsilica膠體硅Albuminprotein白蛋白Bacteria細(xì)菌Carbonblack碳黑Paintpigment顏料色素Yeastcells酵母Milledflour面粉Beachsand海灘沙礫Pollens花粉RO反滲透Ultrafiltration超濾Microfiltration微濾Particle

filtration一般過濾THEFILTRATIONSPECTRUM過濾譜圖NF納濾1.Afeedsolutionwithasoluteconcentrationof3%byweightistreatedbyreverseosmosis.Thepermeatecontains150ppmofsolute.CalculatetheretentionRandtheselectivityfactora.explainwhichofthetwoparametersismoresuitableforthisapplication.2.Air(20%oxygenand80%nitrogen)isseparatedbyamembraneandapermeateconcentrationof75%ofoxygenisobtained.CalculatetheretentionRandtheselectivityfactora.explainwhichofthetwoparametersismoresuitableforthisapplication.3.Giveacompariso