生物分离工程 课件-双语 chapter 5 membrane separation

生物反应器细胞收集细胞破碎沉淀结晶纯化产品制剂BioreactorExtractionCelldisruptionCellharvestingPurificationProductformulationPrecipitationandcrystallizationSupernatantPrecipitationandcrystallizationMembraneseparation

(MF)Membraneseparation

(UF/NF/RO)Membraneseparation

(UF/NF/RO)(ExtraCorporealMembraneOxygenation)人工肺，体外膜肺氧合技术ECMOmechanism不锈钢膜陶瓷膜中空纤维膜聚合物卷式膜Chapter5

Membraneseparation5.1Introduction

5.2Membraneclassification5.3Membraneseparationprocess5.4Membranefouling（膜污染）5.5Membranemodules（膜组件）5.6Application5.7

Newmembraneseparationmethods5.1IntroductionDefinitionAmembraneisathinpermeable（有渗透性的）orsemi-permeablebarrier,whichallowsselectivepassageofdifferentspeciesthroughit,betweentwofluidstreamphases.Thisselectivityisutilizedforseparation.AdvantagesofmembraneseparationDisadvantagesofmembraneseparation(seeP76)AdvantagesofmembraneseparationMildoperatingconditionsSincenophasechangeisinvolvedtheenergyrequirementismodest.Thechemicalandmechanicalstressesontheproductareminimal.Theselectivitytowardsthedesiredproductisgood.Themethodcaneasilybescaledup.5.2MembraneclassificationSyntheticmembranescanbeclassifiedbyfunction,media介质,structureandgeometry几何学.Functionpervaporation渗透蒸发(PV)hemodialysis血液透析(HD)electrodialysis电渗析(ED)ionexchange离子交换(IX)reverseosmosis反渗透(RO)nanofiltration纳滤(NF)ultrafiltration超滤(UF)microfiltration微滤(MF)gasseparations气体分离(GS)mediaormaterials

organicpolymer:e.g.celluloseacetate醋酸纤维素,polyamide聚酰胺,polyester聚酯

inorganicpolymer:e.g.ceramic陶瓷,metal.Geometry几何学sometimesreferredtoas“form,”

film,hollowfiber中空纤维,tube管式Structurereferstothemicrostructureofthemembraneincrosssection横截面Symmetric对称;Asymmetric不对称;Composite复合的各向同性微孔膜致密无孔膜带电膜各向异性膜5.3membraneseparationprocessReverseosmosis反渗透Nanofiltration纳滤Ultrafiltration超滤Microfiltration

微滤Dialysis透析Electrodialysis电渗析Pervaporation渗透蒸发Gasseparation气体分离Table1ThestatusofallofmembraneseparationprocessesFlowschematicofamembranebloodoxygenator表5-1各种膜分离法的原理和应用范围类型传质推动力分离原理

应用举例微滤（MF）压差筛分菌体、细胞和病毒的分离、固液分离超滤（UF）压差筛分蛋白质、肽、多糖的浓缩和纯化，病毒的分离纳滤（NF）压差筛分水软化、有机物和生物活性物质的除盐和浓缩透析（DS）浓差筛分脱盐、除变性剂反渗透（RO）压差筛分盐、氨基酸、糖的浓缩，淡水制造电渗析（ED）电位差离子迁移脱盐、氨基酸和有机酸分离渗透蒸发（PV）压差溶解扩散有机溶剂与水的分离，共沸物的分离（如乙醇浓缩）ReverseOsmosis(RO)Reverseosmosis

（反渗透）

apressuredrivenprocessaimedattheseparationofionicsolutes（离子溶质）andmacromolecules（大分子）fromaqueousstreams.ProcessDivingForce:Hydrostaticpressuredifference静水压力差atapprox.2-10MpaMembraneModules:spiral-wound,hollowfiber半透膜渗透压somegeneralguidelinesformembrane

selectivityMultivalentions（多价离子）

areretainedbetterthanmonovalentions（单价离子）.Dissolvedgasessuchasammonia,carbondioxide,sulfurdioxide,oxygen,chlorineandhydrogensulfide(硫化氢)alwayspermeatewell.RejectionofweakacidsandbasesishighlypHdependent.whentheacidisintheneutralform,therejectionfalls.somegeneralguidelinesformembrane

selectivityRejectionofneutralorganicsolutesgenerallyincreaseswiththemolecularweight(ordiameter)ofthesolute.Componentswithmolecularweightsabove100arewellrejectedbyallreverseosmosismembranes.Negativerejectioncoefficients（系数）,thatis,ahigherconcentrationofsoluteinthepermeatethaninthefeedareoccasionallyobserved,forexample,forphenol（苯酚）andbenzene（苯）withcelluloseacetatemembranesApplicationofReverseOsmosisMembraneProcessIndustrialUseUltrapurewater,boilerwater,processpurewater,dailyindustriesDrinkingWaterSeawaterdesalination,brackishwaterdesalinationWastewaterTreatmentandReuseIndustrialwater,agriculturalwater,indirectdrinkingwater电阻率硅硼Flowschematicofatypicalbrackishwaterreverseosmosisplant.Theplantcontainssevenpressurevesselseachcontainingsixmembranemodules.Thepressurevesselsareina‘Christmastree’arraytomaintainahighfeedvelocitythroughthemodules.卤水Biofouling（生物污染）themostseriousproblemintheoperationofSWRO（海水反渗透）plantstheusualmethodtopreventbiofoulingcontinuouschlorinedosingtointakeseawaterwithsodiumbisulfate(SBS,NaHSO4)dosingattheROportion.Membranesperformancedeteriorationoccurredbyoxidationincaseofbothpolyamide(聚酰胺)andcelluloseacetatemembranes,andbiofoulinghasnotbeensolvedyet.ViablecellcountassessmentinROplantForROmembranemodules,stableoperationisveryimportant.operationtroublesfouling(occupy80%)membranedeteriorationhardwareproblemsSolutions(1)properROmembraneelementswithlow-foulingproperty,(2)properpretreatmenttechnologybeforetheROmembrane,(3)suitablesterilizationmethodsandcleaningTrendsinROmembranetechnologylow-pressuremembranesforoperatingenergyreductioninthefieldofbrackishwaterdesalination.highwaterrecoverywithhigh-pressureresistanceinthelargeseawaterdesalinationmarket.TDS:总溶解固体(TotalDissolvedSolids)TrendsinROmembranetechnologyHighBoronRejectionSWROMembraneBoronexistsasboricacidinthenaturalwater.Potentialtoxicity：malereproductivetractdrinkingwater：below0.5mg/L(WHO,2004)ConventionalSWROmembrane：alittlemorethan90%ofboronrejection－－inadequateWhyisitdifficultforROmembranestoremoveboricacidinwater?SmallsizepKa:9.14–9.25;notionizedinnaturalseawater(pH7.0–8.0)thenexttarget:97or99%boronrejectionNanofiltration(NF)Nanofiltration(NF)apressure-drivenprocess.adifficultprocesstodefineandtodescribe.ProcessDivingForce:0.93-1.59MPaSpecificfeatureshavehighrejections(>90%)tomostdissolvedorganicsoluteswithmolecularweightsabove100–200veryhighrejectionsformultivalentions(>99%)Lowtomoderaterejectionsformonovalentions(0-70%)Nanofiltration(NF)Performancethreeparametersarecrucialfortheoperationofa(nano)filtrationunit:SolventpermeabilityorfluxthroughthemembraneRejectionofsolutesYieldorrecovery(40%~90%)ApplicationdrinkingwaterproductionConcentrationDesalting原生动物藻类胶体Ultrafiltration(UF)Ultrafiltration超滤

apressure-driven,permeability-basedmembraneseparationtechnique.mainlyusedforprocessingmacromoleculessuchasproteins,nucleicacids,andpolysaccharides.poresize:1-100nmProcessDivingForceHydrostaticpressuredifferenceatapprox.0.1-1.0MpaUltrafiltration(UF)mainseparationmechanism

size-basedsieving

butotherfactorssuchaselectrostatic（静电）solute–membraneandsolute–soluteinteractionscansignificantlyaffectseparationmolecularmasscut-off(MWCO)

typicallydefinedasthemolecularweightoftheglobularproteinmoleculethatis90%rejectedbythemembrane.质量好的膜，应有陡直的截断曲线，可使不同分子量的溶质分离完全；反之，斜坦的截断曲线会导致分离不完全。一般选用的膜的额定截留值应稍低于所分离或浓缩的溶质的相对分子量。0.9MWCOA膜B膜溶质相对分子质量截断曲线Ultrafiltration(UF)截留率R（rejection）表示膜对溶质的截留能力定义为R＝1－Cp／Cb式中Cp和Cb分别表示在某一瞬间，溶质在透过液（Permeate）和主料液（Bulk）的浓度。Thecut-offofultrafiltrationmembranesisusuallycharacterizedbysolutemolecularweight,butotherseveralfactorsaffecttheretentivity.theshapeofthemoleculethepHofthefeedsolution胃蛋白酶细胞色素c葡聚糖Ultrafiltration(UF)twomainissuesProductivity:Productivityisquantifiedintermsofthepermeateflux（渗透通量）,thisbeingdefinedasthepermeationrateperunitmembranesurfacearea.Selectivity

Howtomaintainahighpermeateflux?reducingsoluteaccumulationnearthemembranesurface(concentrationpolarization浓差极化)reducingadsorptionanddepositionofsolutesandotherfeedcomponentsonthemembrane(membranefouling)Methods:backflushing,creationofturbulence,introductionofgasbubblesMembranefouling-UFSurfacefoulingthedepositionofsolidmaterialonthemembranethatconsolidatesovertime.canbecontrolledbyhighturbulence（紊流）,regularcleaningandusinghydrophilicorchargedmembranestominimizeadhesiontothemembranesurface.generallyreversibleInternalfoulingcausedbypenetrationofsolidmaterialintothemembrane,whichresultsinpluggingofthepores.generallyirreversiblePurewaterflux:1cm3/cm2・minmacromolecularorcolloidalsolutionsflux:0.1cm3/cm2・minAtypicalcleaningcycle-UF1.Flushthesystemseveraltimeswithhotwateratthehighestpossiblecirculationrate.2.Treatthesystemwithanappropriateacidoralkaliwash,dependingonthenatureofthelayer.3.Treatthesystemwithahotdetergentsolution.4.Flushthesystemthoroughlywithwatertoremovealltracesofdetergent;measurethepurewaterfluxthroughthemembranemodulesunderstandardtestconditions.Evenaftercleaning,somedegreeofpermanentfluxlossovertimeisexpected.Iftherestorationoffluxislessthanexpected,repeatsteps1–3.Membranecleaningmethods-UFregularcleaningwithchemicalsolutionsmechanicalcleaningparticularlyifchemicalcleaningdoesnotrestorethemembranefluxSponge-ball:effectivebutrelativelytime-consumingprocess;infrequentlyBackflushing（反冲）anotherwayofcleaningheavilyfouledmembraneswidelyusedtocleancapillary（毛细管）andceramicmembranemodulesnotusuallyusedforspiral-woundmodulesBackflushingofmembranemodulesbyclosingthepermeateport.ThistechniqueisparticularlyapplicabletocapillaryfibermodulesmembranelifetimeUFalthoughregularcleaning,rarelymorethan2–3yearsmodulesmaybereplacedannuallyincheesewheyorelectrocoatpaintapplications.ROnormallycleanednotmorethanonceortwiceperyearandcanlast4–5years.ApplicationApplications:Concentration,purification,desaltingElectrocoatPaintFoodIndustry:Cheeseproduction,Clarificationoffruitjuice,Processwaterandproductrecyclingbiotechnologyindustry:enzymeproduction,cellharvesting,orvirusproduction铬酸盐/磷酸盐电镀池含镍电镀废水中加入NaOH，产生类似生物大分子胶状Ni(OH)2沉淀。乳清是工业生产干酪和干酪素的副产物，营养价值较高，含有丰富的蛋白质、乳糖以及多种矿物质和水溶性维生素等。毛细管式超滤膜原理内压式超滤膜过滤原理外压式超滤膜过滤原理FlowschemeofthemanufacturingprocessofEngerixBbulkFermentation→celldisruption→precipitation→clarification→ultrafiltration→columnchromatography→ultracentrifugation→columnchromatography→sterilefiltration→sterileHBsAg(purifiedbulkantigen)Microfiltration(MF)Microfiltration微滤

alowpressuremeansofseparatinglargemolecularweightsuspendedorcolloidal胶体的compoundsfromdissolvedsolids.ProcessDivingForce

Hydrostaticpressuredifferenceatapprox.10-500kPaApplications

Sterilefiltration无菌过滤cellharvestingfromfermentationbroths发酵液fractionationofmilkproteinscornsyrup玉米糖浆clarificationSterilefiltrationInatypicalenzymecellharvestandrecoveryprocess,microfiltration微滤replacesthecentrifugationandprecoat预涂filtrationstepsDialysisDialysisaconcentrationgradient

basedseparationprocesswhichusesasemipermeablemembranetoseparatespeciesbyvirtueoftheirdifferentrateofdiffusion

throughmembrane.ApplicationHemodialysis血液透析removalofwastemetabolites代谢物,excessbodywater,andrestorationofelectrolytebalance维持电解质平衡inblood)desaltingDialysisDialysisfordesaltingSelectadialysisbagtreatthedialysismembraneboilingindistilledwatercontainingEDTACheckforleaksaddtheproteinsolution,leavesomespaceattop(1/3volume).stirgentlybystirbaronamagneticstirrerchangethedialysisbufferintermittentlyCompletionStoragebeakerLowsaltbufferhighsaltsampleindialysisbagclipElectrodialysis(ED)Electrodialysis电渗析

anelectrochemicalseparation电化学分离processinwhichmineralsaltsandotherionicspeciesaretransportedthroughionselectivemembranesfromonesolutionintoanotherunderthedrivingforceofadirectcurrent(DC)electricalpotential直流电电势差.Applicationsproductionofpotablewater

饮用水fromseaorbrackish含盐的

water,electroplating电镀

rinse冲洗

recovery,desalting脱盐ofcheesewhey乳清,productionofultrapurewater超纯水etc.Electrodialysis图5-6电渗析原理（A-阴离子交换膜；C-阳离子交换膜）12435ACAC阳极阴极Electrodialysis

PervaporationPervaporationemploymembranesfortheselectiveseparationofdilutesolutesfromavapororliquidintoasolute-enrichedvaporphase.aphasechange相变occursduringtransportthroughthemembrane.Transportthroughthesemembranesiseffectedbymaintainingavapourpressuregradient蒸汽压差

acrossthemembrane.PervaporationApplicationsseparationofethanol乙醇-watermixture,solventrecovery溶剂回收separationofheatsensitiveproducts热敏感产物

orenrichmentoforganicpollutants有机污染物的富集etc.脱水渗透蒸发－分馏发酵精馏器MicrofiltrationMembraneDistillationPervaporationgasseparationDrivingforcethepressuredifferenceacrossthemembraneSeparationisachievedbecauseofdifferencesintherelativetransportratesofthefeedcomponents.Componentsthatdiffusemorerapidlybecomeenrichedinthelowpressurepermeatestreamwhiletheslowercomponentsareconcentratedintheretentateorresiduestream.SimplifiedflowschematicofthePRISMmembranesystemtorecoverhydrogenfromanammoniareactorpurgestream.Atwo-stepmembranesystemisusedtoreducepermeatecompressioncostsHELIUM氦气为无色无味，不可燃气体，空气中的含量约为百万分之5.2。化学性质完全不活泼，通常状态下不与其它元素或化合物结合。理论上可以从空气中分离抽取，但因其含量过于稀薄，工业上从含氦量约为0.5%的天然气中分离、精制得到氦气。利用其－268.9℃的低沸点，液氦可以用于超低温冷却。Application气球和飞艇人造空气保护气体：2000年美国消耗的所有氦气中，有18%用在了焊接上，还有16%用作其他工业的保护气。超低温冷冻剂：气冷式核反应堆的工作流体、卫星发射、导弹武器工业、低温超导研究、半导体生产等方面具有重要用途。Production氦气最主要的来源是天然气。天然气中最高则可含7.5%的氦，是空气的一万五千倍。可是这种高氦的天然气矿藏并不多，因为天然气中的氦气是铀之类的放射性元素衰变的产物。只有在天然气矿附近有铀矿时，氦气才能在天然气中汇集。美国氦气资源占50%以上，中国仅占0.2%。美国生产的氦气要占世界总产量的80%以上。2007年，美国将氦气核定为战略物资而限制粗氦产量，导致全球液氦价格由原来60～80元/每升，上涨到目前200元/每升以上。SummaryRONFUFMFDialysisEDPVGS分离原理筛分筛分筛分筛分筛分离子迁移溶解扩散筛分推动力压差压差压差压差浓差电位差压差压差工作压力2-10MPa0.9-1.5MPa0.1-1.0MPa0.05-0.5MPa13.5MPa应用盐、氨基酸、糖的浓缩，淡水制造水软化、有机物和生物活性物质的除盐和浓缩水软化、有机物和生物活性物质的除盐和浓缩菌体、细胞和病毒的分离、固液分离脱盐、除变性剂脱盐、氨基酸和有机酸分离有机溶剂与水的分离，共沸物的分离（如乙醇浓缩）多种气体的分离，提浓工艺5.4membranefoulingDefinitionTheprocessthatresultsinadecreaseinperformanceofamembrane,causedbythedepositionofsuspendedordissolvedsolids

ontheexternalmembrane

surface,onthemembranepores,orwithinthemembranepores.(TheInternationalUnionofPureandAppliedChemistry)Contamination

ofmembranescausesahigherenergyuse,ahighercleaningfrequencyandashorterlifespanofthemembrane.Membranecontaminationisusuallycalledfouling.TypesofMembranefouling膜污染PorePlugging孔堵塞Adsorption吸附Concentrationpolarisation浓差极化GelLayerformation凝胶层形成FactorsaffectingfoulingFeedMembranetypeFlowConfigurationTransmembranepressureControllingFoulingBackflushingFeedmodificationMembranechoiceForcrossflowuselowTMP(Transmembranepressure.)CleaningAnillustrationoftheefficiencyofback-pulsinginremovingfoulingmaterialsfromthesurfaceofmicrofiltrationmembranes.DirectmicroscopicobservationsofMoresandDavisofcelluloseacetatemembranesfouledwitha0.1wt%yeastsuspension.Themembranewasbackflushedwithpermeatesolutionat3psiforvarioustimes.5.5membranemoduleshollowfibermembranemodule（中空纤维膜组件）tubularmembranemodule（管式膜组件）plateandframemodule（平板式膜组件）SpiralWoundmodule（卷式膜组件）ModuleTypeCharacteristicsFlatplateSpiralWoundShellandTubeHollowFibrePackagingdensity(m2/m3)ModerateModerateLowHighFluidmanagementGoodGoodHighpumpingcosts