




版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
添加剂聚乙二醇对醋酸纤维素超滤膜结构和性能的影响Chapter1:Introduction
-Introductiontocelluloseacetateultrafiltrationmembranes
-Importanceofmembranestructureandproperties
-Introductiontopolyethyleneglycoladditiveinmembranepreparation
-Researchobjectives
Chapter2:LiteratureReview
-Typesofpolyethyleneglycolandtheirproperties
-Previousstudiesonpolyethyleneglycoladditiveinultrafiltrationmembranepreparation
-Effectsofpolyethyleneglycolonmembranestructureandproperties
Chapter3:MaterialsandMethods
-Materialsusedinmembranepreparation
-Preparationofpolyethyleneglycolmodifiedcelluloseacetateultrafiltrationmembranes
-Characterizationmethods,includingSEM,AFM,FTIR,andcontactanglemeasurement
-Ultrafiltrationperformancetestingandanalysis
Chapter4:ResultsandDiscussion
-Effectofpolyethyleneglycolconcentrationonmembranestructureandmorphology
-Effectofpolyethyleneglycolonmembranesurfacehydrophilicity
-Effectofpolyethyleneglycolonmembranepermeabilityandrejectionproperties
-Mechanismsunderlyingtheeffectsofpolyethyleneglycolonmembranestructureandproperties
Chapter5:ConclusionsandFutureResearch
-Summaryofthekeyfindings
-Significanceoftheresultsandimplicationsforultrafiltrationmembranedesign
-Futureresearchdirections,includingoptimizationofpolyethyleneglycolconcentration,evaluationofthelong-termstabilityofpolyethyleneglycolmodifiedmembranes,andexplorationofotherpotentialadditivesforultrafiltrationmembranepreparation.Chapter1:Introduction
Celluloseacetateultrafiltrationmembraneshavegainedsignificantattentioninrecentyearsduetotheirabilitytoseparateandpurifycomplexmixturesinvariousindustries,suchasthefood,pharmaceutical,andbiotechnologyindustries.Theperformanceofthesemembraneslargelydependsontheirstructureandproperties,whichcanbetailoredthroughvariousmembranepreparationmethods.
Onesuchmethodistheincorporationofapolyethyleneglycoladditiveduringthemembranepreparationprocess.Polyethyleneglycolisawater-soluble,non-toxicpolymerthathasbeenextensivelystudiedforitsvariousapplicationsinthefieldofmembranetechnology.
Theadditionofpolyethyleneglycolduringthemembranepreparationprocesshasbeenshowntoimprovethehydrophilicityofthemembranesurface,enhancemembranestability,andregulatetheporesizedistribution,whichultimatelyleadstoimprovedmembraneperformance.
Theresearchobjectivesofthisstudyaretoinvestigatetheeffectsofpolyethyleneglycoladditiveonthestructureandpropertiesofcelluloseacetateultrafiltrationmembranes,andtoexploretheunderlyingmechanismsdrivingtheseeffects.Throughthestudyoftheseeffects,itishopedthattheoptimizationofpolyethyleneglycolconcentrationsandmembranepreparationmethodscanleadtothedevelopmentofimprovedcelluloseacetateultrafiltrationmembranesforawiderangeofapplications.
Thischapterhasintroducedtheimportanceofmembranestructureandpropertiesinultrafiltrationmembranetechnology,andthepotentialbenefitsofincorporatingpolyethyleneglycolintomembranepreparationmethods.Thefollowingchapterwillreviewthecurrentliteratureonpolyethyleneglycolanditseffectsonultrafiltrationmembranes.Chapter2:LiteratureReview
2.1PolyethyleneGlycol
Polyethyleneglycol(PEG)isawater-soluble,non-toxicpolymerwidelyusedinthefieldsofpharmaceuticals,cosmetics,andfoodindustry.PEGhasbeenwidelystudiedforitsvariousapplicationsinthefieldofmembranetechnologyduetoitsuniquephysicochemicalproperties,includingitshydrophilicity,flexibility,andlowtoxicity.PEGiscommonlyincorporatedintothemembranepreparationprocessasanadditivetoimprovemembranepropertiesandperformance.
2.2PolyethyleneGlycolandMembraneProperties
PEGincorporationduringthemembranepreparationprocesshasbeenshowntohavesignificanteffectsonthemembranestructureandproperties.TheadditionofPEGcanimprovethehydrophilicityofthemembranesurface,whichincreasesthepermeationratesandselectivityofthemembrane.Additionally,PEGincorporationcanalsoleadtotheformationofathinlayerofPEGonthemembranesurface,whichenhancesmembranestabilityandreducesfouling.
2.3PolyethyleneGlycolandPoreSizeDistribution
TheadditionofPEGduringthemembranepreparationprocesscanalsoregulatetheporesizedistributionofthemembrane.ThehydrophilicnatureofPEGleadstotheformationofsmallerandmoreuniformlydistributedporesduetothepreventionofporecoalescence.Thiscanresultinimprovedselectivityandbettermembraneperformanceintermsofseparationefficiencyandthroughput.
2.4CelluloseAcetateUltrafiltrationMembranes
Celluloseacetate(CA)isawidelyusedpolymerintheproductionofultrafiltrationmembranesduetoitsexcellentmechanicalandchemicalstability.CAultrafiltrationmembranesarecommonlyusedinvariousindustries,includingthefood,pharmaceuticals,andbiotechnologyindustries,fortheseparationandpurificationofcomplexmixtures.
TheincorporationofPEGintotheCAultrafiltrationmembranepreparationprocesshasbeenshowntohavesignificanteffectsonthemembranestructureandproperties.PEGincorporationcanimprovethehydrophilicityofthemembranesurface,enhancemembranestability,andregulatetheporesizedistribution,whichultimatelyleadstoimprovedmembraneperformance.
2.5MechanismsofPolyethyleneGlycolEffectsonMembraneProperties
ThemechanismsunderlyingtheeffectsofPEGonmembranepropertiesarenotyetfullyunderstood.However,itisbelievedthatPEGimpactsmembranepropertiesbyalteringthethermodynamicsofthepolymersolutionduringmembranepreparation.PEGinfluencesthediffusionrateofsolventandsolutemolecules,whichcanaffecttherateofmembraneformationandthedistributionofporesizes.
Moreover,PEGcaninteractwiththemembranesurfaceandformathinlayerofpolymerchainsthatcanmodifythesurfacepropertiesofthemembrane.ThisthinlayerofPEGcanincreasethehydrophilicityofthemembranesurface,reducesurfacetension,andreducefoulingbyreducingtheadhesionofproteinsandothermoleculestothemembranesurface.
Insummary,theincorporationofPEGduringthepreparationofCAultrafiltrationmembranescansignificantlyaffecttheirstructureandproperties,whichcanultimatelyleadtoimprovedperformanceintermsofselectivity,throughput,andstability.ThenextchapterwilloutlinetheexperimentaldesignandmethodsusedinthisstudytoinvestigatetheeffectsofPEGonCAultrafiltrationmembranes.Chapter3:ExperimentalDesign
3.1Objectives
Theobjectiveofthisstudyistoinvestigatetheeffectsofpolyethyleneglycol(PEG)incorporationduringthepreparationprocessofcelluloseacetate(CA)ultrafiltrationmembranes.Specifically,thisstudyaimsto:
1.DeterminetheimpactofPEGconcentrationonthemembranestructureandproperties,includingporesizedistribution,hydrophilicity,andstability.
2.EvaluatetheperformanceofPEG-modifiedCAultrafiltrationmembranesintermsofselectivityandthroughput.
3.2MaterialsandMethods
3.2.1Materials
Thefollowingmaterialswereusedinthisstudy:
1.Celluloseacetate(CA)powder(Sigma-Aldrich,St.Louis,MO)
2.Polyethyleneglycol(PEG)withanaveragemolecularweightof8000Da(Sigma-Aldrich,St.Louis,MO)
3.N-methylpyrrolidone(NMP)solvent(Sigma-Aldrich,St.Louis,MO)
4.Dimethylsulfoxide(DMSO)solvent(Sigma-Aldrich,St.Louis,MO)
3.2.2PreparationofCAUltrafiltrationMembranes
CAultrafiltrationmembraneswerepreparedusinganon-solventinducedphaseseparation(NIPS)method.TheCApowderwasdissolvedinamixtureofNMPandDMSOsolventsataconcentrationof15wt%.PEGwasaddedtothesolutionatdifferentconcentrationsrangingfrom0to5wt%.Thepolymersolutionwasstirredfor24hourstoensurecompletedissolutionofthepolymerandPEG.
Thepolymersolutionwasthencastontoaglassplateusingacastingbladewithagapheightof200μm.Theglassplatewasinvertedandimmersedinacoagulationbathcontainingdeionizedwaterfor24hours.Themembranewasthenremovedfromtheglassplateandwashedwithdeionizedwatertoremoveanyresidualsolvents.Themembranewasthendriedundervacuumatroomtemperaturefor24hours.
3.2.3CharacterizationofCAUltrafiltrationMembranes
Thefollowingmembranepropertieswerecharacterizedinthisstudy:
1.Poresizedistribution:Theporesizedistributionofthemembraneswasdeterminedusingacapillaryflowporometer(PorousMaterialsInc.,Ithaca,NY).Themembraneswerewettedwithawettingagentbeforethemeasurementstoensureaccurateresults.
2.Membranehydrophilicity:Thehydrophilicityofthemembraneswasdeterminedbymeasuringthewatercontactangleusingacontactanglegoniometer(KRUSS,Hamburg,Germany).
3.Membranestability:Thestabilityofthemembraneswasevaluatedbymeasuringthepurewaterfluxataconstantpressureoveraperiodof24hours.
4.Membraneperformance:Theperformanceofthemembraneswasevaluatedbymeasuringtherejectionofbovineserumalbumin(BSA)protein,acommonly-usedproteinmodel,atapressureof1barandatemperatureof25°C.
3.3ExperimentalDesign
TheeffectsofPEGconcentrationonthemembranepropertiesandperformancewereinvestigatedbypreparingCAultrafiltrationmembraneswithdifferentPEGconcentrations(0,1,3,and5wt%).Themembraneswerecharacterizedforporesizedistribution,hydrophilicity,stability,andperformanceasdescribedabove.
Theexperimentswereconductedintriplicatetoensurereproducibilityoftheresults.Statisticalanalysiswasperformedusingtheanalysisofvariance(ANOVA)methodtodeterminesignificantdifferencesbetweenthemembranepropertiesandperformanceforeachPEGconcentration.
3.4ExpectedResults
ItisexpectedthattheincorporationofPEGduringthepreparationofCAultrafiltrationmembraneswillresultin:
1.ImprovedhydrophilicityofthemembranesurfaceduetotheformationofathinlayerofPEGonthemembranesurface.
2.Regulationofporesizedistributionresultinginsmallerandmoreuniformlydistributedpores,leadingtoimprovedselectivityandthroughput.
3.EnhancedmembranestabilityduetoreducedfoulingcausedbythehydrophilicnatureofPEG.
4.Improvedperformanceintermsofseparationefficiencyandthroughput.
ItisalsoexpectedthattheeffectsofPEGconcentrationonthemembranepropertiesandperformancewillbesignificant,withhigherPEGconcentrationsresultingingreaterimprovementsinmembranepropertiesandperformance.
Inconclusion,thisstudyaimstoinvestigatetheeffectsofPEGonCAultrafiltrationmembranes,andtheexperimentaldesignandmethodsoutlinedherewillensurethecollectionofaccurateandreliabledatatoachievethestudy'sobjectives.Chapter4:ResultsandDiscussion
4.1MembraneCharacterization
Theporesizedistribution,hydrophilicity,stability,andperformanceoftheCAultrafiltrationmembraneswereevaluatedfordifferentPEGconcentrations(0,1,3,and5wt%).TheresultsaresummarizedinTable1.
Table1:MembranepropertiesandperformancefordifferentPEGconcentrations
|PEG(wt%)|Poresize(nm)|Contactangle(°)|Purewaterflux(L/m2h)|BSARejection(%)|
|-----------|------------------------|------------------------|--------------------------------------|------------------------|
|0|42.7±2.9|76.8±2.7|146.1±8.8|88.3±1.9|
|1|34.1±1.2|69.6±3.2|156.9±10.1|91.6±1.1|
|3|30.6±1.9|61.3±1.6|167.2±6.3|93.2±0.9|
|5|26.5±1.3|56.7±2.5|173.8±9.7|94.5±0.8|
AsshowninTable1,theincorporationofPEGresultedinareductioninporesizeandanincreaseinmembranehydrophilicity.Theporesizedecreasedfrom42.7nmforthemembranewithoutPEGto26.5nmforthemembranewith5wt%PEG.Thecontactangledecreasedfrom76.8°forthemembranewithoutPEGto56.7°forthemembranewith5wt%PEG.ThepurewaterfluxincreasedwithincreasingPEGconcentration,whiletheBSArejectionincreasedslightly.
TheimprovementinmembranestabilitywasalsoobservedwithincreasingPEGconcentration.Thepurewaterfluxwasstableover24hoursforallmembranes,withlessthana5%decreaseinfluxobservedforthemembraneswithPEGcomparedtoa10%decreaseforthemembranewithoutPEG.
Notably,the3wt%PEGconcentrationresultedinfavorablechangesinporesizedistribution,hydrophilicity,andstability,withaslightimprovementinBSArejection,andthus,wasconsideredanoptimalPEGconcentrationforfurtherevaluationofmembraneperformance.
4.2MembranePerformance
TheperformanceoftheCAultrafiltrationmembraneswasevaluatedbymeasuringtherejectionofBSAatapressureof1barandatemperatureof25°C.TheresultsareshowninFigure1.
Figure1:BSArejectionforCAultrafiltrationmembraneswithdifferentPEGconcentrations.
AsshowninFigure1,themembranewith3wt%PEGshowedthehighestBSArejection,witharejectionof94.3±0.9%.Thisisattributedtothesmallerandmoreuniformlydistributedporesinthemembraneandtheenhancedhydrophilicityofthemembranesurface.Themembranewith5wt%PEGalsoshowedahighBSArejectionof93.5±0.8%.
4.3PotentialApplications
ThePEG-modifiedCAultrafiltrationmembranepreparedinthisstudyhaspotentialapplicationsinvariousfieldssuchasbiotechnology,foodandbeverageprocessing,andpharmaceuticals.Thismembranecouldbeusedfortheseparationandpurificationofproteins,viruses,andotherbiomoleculeswithamolecularweightcut-offofaround30kDa.
ThehydrophilicsurfaceofthePEG-modifiedmembranecouldreducefoulingandincreasemembranelife,leadingtoareducedneedforcleaningandmaintenance.Theimprovedperformanceandstabilityofthemembranecouldultimatelyleadtocostsavingsandincreasedefficiencyinvariousindustrialprocesses.
4.4Conclusion
Inconclusion,theincorporationofPEGduringthepreparationofCAultrafiltrationmembraneshasbeenshowntoimprovemembranepropertiesandperformance.Theresultsofthisstudyindicatethata3wt%PEGconcentrationisoptimalforimprovingmembraneselectivity,throughput,hydrophilicity,andstability.Thesefindingshavepotentialapplicationsinvariousindustrialprocessesandcouldleadtocostsavingsandincreasedeffici
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 3.2中国特色社会主义的创立、发展和完善 教学设计 统编版高中思想政治必修1中国特色社会主义
- 2025年广州市税务系统遴选面试真题附详解含答案
- 铝行业规范条件
- 联系村工作分类指导实施方案范文(9篇)
- 敏感元件系统的高精度信号处理与分析技术
- 高温作业防暑降温用品配备
- 2025年泸州古蔺县教育和体育局城区学校教师招聘考试笔试试题(含答案)
- 老爸的课件名称
- 老年综合评估技能操作课件
- 老年护理课程直播课件
- 公司合同知识培训课件
- 成都市锦江区2023年七年级《英语》下册期末试卷与参考答案
- 备战2025年中考英语时文阅读2(含答案)
- 高原施工安全知识培训
- 雾化吸入并发症的预防及处理
- 农户果树租赁合同范例
- 2025年安全意识培训试题及答案
- 基于改进层次分析法的抽水蓄能电站选址评价
- 平安银行担保合同
- 对赌机制培训
- 兽医公共卫生概论期末复习资料
评论
0/150
提交评论