1、membranes膜過程的驅動力壓力驅動- RO, NF，UF, MF其它過程-滲析（濃度差）電滲析（電位差）壓力驅動的膜過濾膜 MF UF NF RO孔尺寸減小泵壓力增加 高分子材料 (PAN, PES, CA, PVDF). 鑄膜液制備：聚合物+有機溶劑(NMP, DMF, acetone等易與水互溶). 添加其它助劑 (pore-formers or non-solvents). 凝固浴 （主要用水和其它聚合物不良溶劑構成，通過相分離產生the pores 和the membrane body)必需品 PES聚合物 NMP 溶劑 水 玻璃片 刮膜器 NMP甲基吡咯烷酮PES聚醚酚Poly

2、 Sulfon (PS)PS in NMP solutionCleaning glassplates importantglassplatesFilling the knife with PS solutionMembrane knife (0,2 mm)Creating a membrane filmPut slowly in the water for.Move very gently to leftMembrane is floating after coagulationAfter coagulationTake of a membraneOut of the waterThe pho

3、to of the produced membraneMake sheets of it in a moduleMake a module of itMore than one membraneSubmerge in a MBR tank Porous vs Non Porous Hydrophilic vs Hydrophobic Polymeric vs InorganicHydrophilic親水 Hydrophobic疏水Porous Non PorousSymmetric Asymmetric Dense (Non porous)Porous SymmetricPorous asym

4、metricRO, NFUF, MFMFSkinSupportPorous Symmetric MembranesNuclepore Membrane核徑跡成孔核徑跡成孔Cellulose MembraneSymmetric membraneAsymmetric MembranesDense LayerPorous supportFiber SupportPore sizeCeramic membrane pictures (CEM)Membrane structure structure: symmetric asymmetric shapes: flat sheet tubular: tu

5、be(d 3 mm) capillary (0.5 d 3.0 mm) hollow fibre(d 0.5 mm)Module shapes Flat Sheet Spiral Wound Tubular Hollow Fiber Contained vs SubmergedFlat sheet moduleMembraneFeedResiduePermeatePermeate014-DWG-MWPlate and Frame ModuleUFPolyacrylo nitrile(PAN)Polyvinylidene fluoride(PVF)Polysulfone(PS)Sulfonate

6、d Polysulfone(SPS)Tubular and capillary membranes Tubular membranewww.vito.beTubular membranes (contained)Hollow Fiber (capillar)Outside In VS Inside OutFrom Catalog of TorayCapillary 8 inch moduleMonolith (demo)Inorganic Membranes- CeramicMF, UFRecently NF- Porous glass- ZirconiumSpiral-Wound RO/NF

7、 ModuleFlow INSpacerMembranePermeateConcentrateCollection pipeFeed flowFeed flowPerm eate flowMem braneMem braneFeed spacerFeed spacerResidue flowPerm eate015-DW G-MWYou can make your own spiral wound module today! Two A4 papers Cotton sheet A4 (if available) Shears to cut Glue for paper Plastic tub

8、e with a slid (prefabricated)Reverse Osmose-installation+/- various configurationsFeedPermeatePermeateFeedRetentateDead endCross-flowDeadend and CrossflowOperation modesMembrane filtration dead-endMembraneWaste waterPermeatefeedMembrane filtration cross flowWaste waterPermeateconcentratefeedmembrane

9、Air injectionDead-end FiltrationtimeCross-flow filtrationtimeSemi dead-end filtrationCross-flow filtration Advantages:turbulent flowcontinuous concentrate dischargecontrol of cake-layer build-up Disadvantages:more complex process layouthigh(er) energy consumptionhigh(er) investment costCascade singl

10、e pass systemFeedRetentateConcentrateTwo-stage recirculation systemConcentrateFeedPermeatePermeateStage 1Stage 2Feed pumpRecirculation pumpFouling of membranes Fouling Reversible fouling Irreversible fouling Biofouling Pore blocking Scalingfoul a.1. 骯臟的,污濁的;2. 惡臭的;(食物)腐敗的;3. 邪惡的,可惡的;4. 下流的,惡語咒罵的;5.

11、(天氣等)惡劣的;(風)逆的;6. (比賽中)犯規的;7. (水管等)堵塞的;8. (繩索等)被纏住的ad.1. 違反規則地;不正當地n.1. (比賽中)犯規C(+against/on)vt.1. 弄臟;污染;玷污;2. 使堵塞;3. 纏住;4. 碰撞vi.1. 腐敗,腐爛;2. (管道等)堵塞(+up);3. (比賽中)犯規;4. (繩索等)纏結Resistance ModelI =ER1+R2+R3ER1R2R3IRmRcRgRpJvJv =DPm(Rc+Rg+Rp +Rm)Separation of resistance factors to Cake, Gel, Plugging, M

12、embrane.Rejection by UF/MF membranesGlobular ProteinLinear polymerSolutePepsinCytochrome CPolydextranMW (kDa)3513100Rejection (%)90700 Porous supportSelective membrane skinGlobularproteinLinearmacromoleculeCake layer formationMembraneParticleColloid/proteinCake/fouling layerFlow directionDriving for

13、cepFouling in MF/UFDecrease in flux due to: Pore-plugging, adsorption and cake-layer formation No concentration polarization of salts no scaling In general concentrated feed solutions containing large particles (size 10 nm 25 m).This results in low back-diffusion rates, fast cake layer build-up and

14、pore blocking low product-fluxes (1/10 of the CWF) Complex cake layer structureFouling in NF/ROFouling behavior differs from UF/MF due to: Lower fluxes and presence of smaller molecules higher back-diffusion and in general no thick cake layer formation Charged membrane surfaces (in general negative)

15、 adsorption of colloids and biological matter Scaling (CaSO4, CaCO3)Fouling reduction/cleaning Membrane properties and module design Optimum process conditions (low TMP) Cleaning regimehydraulic cleaning (backwash, forward flush and airflush)chemical cleaningrelaxation Pre-treatment of the feed (flo

16、cculation/coagulation, pH adjustment)Backwash (= Backflush)SuspensionMembranePermeateFiltration modeBackflushing modeto drainFluxTimewith backflushingwithout0negative flowSuspensionMembranePermeateFiltration modeBackflushing modeto drainFluxTimewith backflushingwithout0negative flowBackwash (= Backf

17、lush)Forward Flush productionforward flushBack Flush productionforward flush & back flushpermeateAirFlushbubble flowslug flowannular flowForward Flush with airflush productionforward flush with airflush & backflushMembrane filtration semi dead-endMembraneWaste waterPermeatefeedDead-end production-ru

18、n, startpermeatepermeatepermeatepermeatefeedMembrane moduleDead-end at end of production runBuilding up fouling layerProduction of permeate decreases at constant TMPpermeatepermeatepermeatepermeatefeedDead-end with backflushBackflush with permeate duringproductionconcentratefeedpermeatepermeateperme

19、atepermeateDead-end with backwash & airflushAir injectionfeedpermeatepermeatepermeatepermeateBackwash with airflush results in lower permeate useAir injectionMembrane filtration cross flowWaste waterPermeateconcentratefeedmembraneAir injectionCross flow High sheering forces in membrane module Low fouling layer build up Higher energy demand Higher recovery Applicated for higher MLSS contentsAt t = 156 hAt t = 372 hThe effect of backwash on permeate production:Relaxation Give the membrane time to relax Fouling will loosen Me