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西安科技大学硕士学位论文Pickering乳液的制备及应用研究姓名：刘登卫申请学位级别：硕士专业：化学工艺指导教师：贺拥军2011论文题目：Pickering乳液的制备及应用研究专业：化学工艺硕士生：刘登卫(签名)指导教师：贺拥军(签名)摘要Pickering乳液是以固体粒子替代传统化学乳化剂制得的热力学和动力学均稳定的分散体系。Pickering乳液由于其成本低、无毒和环保等特性，在食品、医药和化妆品等领域具有重要的应用价值。本文以固体粒子为乳化剂制备了稳定的Pickering乳液，考察了影响Pickering乳液形成和稳定性的因素，并研究了Pickering乳液作为分离介质的应用性能。采用Stöber法制备了SiO2粒子，用直接沉淀法制备了ZnO粒子和MgO粒子，利用晶相生长逐层包覆的方法制备了SiO2/ZnO复合粒子，讨论了反应物浓度、滴加方式和滴加速度等因素对固体粒子形貌和分散性的影响。SEM测试表明，SiO2粒子分散性良好，平均粒径约为300nm；ZnO粒子呈针状结构，平均直径为20nm；ZnO在SiO2表面分布不均，改变锌盐溶液的浓度和滴加速度，可以得到ZnO组分含量不同的SiO2/ZnO复合粒子；MgO粒子有球形和立方晶形结构，平均粒径约为100nm。FTIR检测表明，SiO2、ZnO、SiO2/ZnO和MgO粒子表面均有大量的羟基。XRD分析证明，MgO结晶度较高。以SiO2、ZnO、SiO2/ZnO和MgO粒子为乳化剂，制备了O/W型Pickering乳液，考察了固体粒子种类、复合粒子组分含量、油水体积比、连续相中电解质和表面活性剂等因素对乳液稳定性的影响。以三氯甲烷为油相时，基于SiO2和ZnO制备的乳液很不稳定，而SiO2/ZnO和MgO均能得到稳定的乳液，且SiO2/ZnO中ZnO组分含量越高，乳液滴越小。在MgO稳定的三氯甲烷/水乳液中，增加油水体积比，乳液稳定性下降，但没有发生相转变。当连续相中电解质浓度增加时，乳液稳定性下降，且Na2CO3比NaCl的作用强。给MgO稳定的三氯甲烷/水乳液中加入表面活性剂，乳液滴变小且更稳定；给表面活性剂稳定的三氯甲烷/水乳液中加入固体粒子，乳液滴平均直径增大而稳定性也增加。以SiO2/ZnO稳定的三氯甲烷-苯乙烯/水乳液为介质，进行了静态和动态分离甲基紫的研究。在静态分离下，Pickering乳液在30min内就趋于分离饱和，温度对分离效果的影响不大，而增加乳液量和增大甲基紫水溶液浓度可以提高乳液分离能力，分离前后乳液滴的形貌变化不大。在动态分离下，增加Pickering乳液量、降低甲基紫溶液进水浓度和流速，可以延长穿透时间和提高乳液分离能力，分离后乳液滴发生了凹陷、扁平等变形。以MgO稳定的三氯甲烷/水乳液为介质，进行了苯胺的静态和动态分离。在静态分离下，Pickering乳液在10min以就达到了昀大分离量，增加乳液量和分离级数，分离效率提高；增大MgO用量，分离效率先增大后减小。单级分离效率低于70%，三级分离效率超过98%，分离前后乳液滴的形貌变化不大。在动态分离下，增加乳液用量、减小进水流速和进水浓度，穿透时间延长。关键词：固体粒子；Pickering乳液；稳定性；甲基紫；苯胺；分离研究类型：基础研究Subject:StudyonthePreparationandApplicationofPickeringEmulsionsSpecialty：ChemicalTechnologyName：LiuDengwei(Signature)Instructor：HeYongjun(Signature)ABSTRACTAsathermodynamicanddynamicstabilitysystem,solid-stabilizedemulsionsarestabilizedbysolidparticlesasemulsifiersinsteadoftraditionalchemicalsurfactants,whichareoftencalledPickeringemulsions.Becauseoflowcost,non-toxicandenvironmental,Pickeringemulsionsplayanimportantroleinfood,pharmaceuticalandcosmeticsetal.Inthispaper,Pickeringemulsionsstabilizedbysingleandcompositeparticleswereprepared,thefactorsinfluencedthestabilityofPickeringemulsionswerediscussed,andtheapplicationinseparationprocessofPickeringemulsionswasinvestigated.UsingStöbermethod,SiO2particleswerepreparedbyhydrolysisreactionoftetraethoxysilane(TEOS).ZnOandMgOparticleswerepreparedbydirectprecipitationmethod.SiO2/ZnOcompositeparticleswerepreparedwithalayerbylayermethodbycoatingZnOonthesurfaceofSiO2particles.SEMshowedthatSiO2particlesweredispersedwellandsphericalwithanaveragediameterof300nm,ZnOparticleswereneedle-likemorphologywithanaveragesizeof20nm,MgOparticleshadbothsphericalanddubiccrystalstructurewithanaveragediameterof100nm,ZnOwereunevendistributedonthesurfaceofSiO2anddifferentcomponentscompositeparticlescouldbepreparedbychangingtheconcentrationofzincsaltsolutionandthedropsofliquidspeed.FTIRshowedthatalargenumberofhydroxylgroupsonthesurfaceofSiO2,ZnO,SiO2/ZnOandMgO.XRDconfirmedMgOhadahighdegreeofcrystallization.Theoil-in-waterPickeringemulsionsstabilizedbySiO2,ZnO,SiO2/ZnOandMgOparticlesasemulsifierswereprepared,andthefactorsofsolidparticlestype,componentcontentofcompositeparticles,oil-waterratio,electrolyteincontinuousphaseandsurfactantsontheformationandstabilityoftheemulsionswereinvestigated.TheresultsshowedthattheemulsionsstabilizedbySiO2/ZnOandMgOwereverystable,butbySiO2andZnOwerenotwhilechloroformasoilphase.ThestabilityofPickeringemulsionsstabilizedbyMgOdecreasedwhenoil-waterratioincreased,butnophaseinversionoccurred.Thestabilitydecreasedwhenelectrolyteconcentrationwashigh,andNa2CO3wasstrongerthanNaCl.ThedropletsbecamesmallerandmuchmorestablewhensurfactantswereaddedintheemulsionsstabilizedbyMgOparticlesasemulsifierandchloroformasoil,andjoinedsolidparticlestothechloroforminwateremulsionsstabilizedbysurfactants,thesizeandthestabilityofthedropletswereincreased.Thestaticanddynamicseparationofmethylvioletbasedonthechloroform-styreneinwateremulsionsstabilizedbySiO2/ZnOparticles.TheresultsshowedthatPickeringemulsionstendedtoseparationsaturationwithin30min,buttemperaturehadlittleinfluence,theseparationefficiencycouldbeimprovedbyincreasingtheamountofemulsionsandtheconcentrationofmethylvioletonthestaticseparation,andthedropletschangedlittlebeforeandafterseparation.Thepenetrationtimeextendedandtheseparationabilityofmethylvioletincreasedwhenincreasingtheamountoftheemulsions,decreasingtheconcentrationofmethylvioletandflowrate,andthedropletschangeddepression,flatandsoon.ThestaticanddynamicseparationofanilinewascarriedoutwithPickeringemulsionsasseparationmedia.TheresultsshowedthatPickeringemulsionsreachedtothemaximumcapacity,withincreasingtheamountofemulsionsandtheextractionstages,thestaticextractionefficiencyincreased,increasingMgOparticles,theextractionefficiencyraisedfirstandthendecreased,andthestaticextractionefficiencyofsingle-stagewas70%,whilethatofthree-stagesexceeded98%.Thedynamicextractionbehaviorofanilinefromaqueoussolutionwassimilartothatofadsorptionprocedureinfixedbed,withtheincreaseofthevolumeamountofPickeringemulsions,thedecreaseofinletrateandinitialanilineconcentration,thedynamicextractionefficiencyincreased,thepenetrationtimewasprolongedandthedropletsha