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1、聚丙烯中空纤维膜二（2-乙基已基）膦酸体系萃取水溶液中铜离子的研究150助财抖2006年第1期(37)卷ExtractingcopperinpolypionsfromaqueoussolutionusingD2EHPAropylenehollowfibremembrane.ZUODan-ying,ZHUBao-ku,WANGShao-hong,XUYou-yl(DepartmentofPolymerScienceandEngineering,ZhejiangUniversity,Hangzhou310027.China)Abstract:Inthispaper,themembraneextra
2、ctionofcopperionswascarriedoutusinghydrophobiepolypropylenehollowfibermembranemodulesandkerosenesolutionscontainingDi-(2-ethylhexy1)phosphoricacidasextractant.Theinfluencesofoperationconditionsontheextractionefficiencywerestudied.Experimentalresuhsshowedtheextractionefficiencywereindependentoftheflo
3、wvelocitiesoftwophasesandtheareasofmembrane.However,thechangesofpHofaqueousphaseandinitialCuz+coD_-centrationintheorganicphasemadetheextractionefficiencyvaryfrom4099%.Thiswasbecausethattheoverallmasstransferresistancewascontrolledbyinterfaeialreactionsratherthantheaqueousandorganicboundarylayer.TheI
4、IlasstransferresistancewasindependentofCuz+athighcopperionsconcentration;however,whenthecopperconcentrationwaslow.theIIlasstransferresistanceincreasedasCu+concentrationgotsmaller.andthemasstransfercoefficientdecreasedasCuz+coneen.trationgotsmaller.Keywords:polypropylenehollowfibermembrane;membraneex
5、tractioncopperionsDb(2一ethylhexy1)phosphoricacidCLCnllmber:TQ028.8X758DocumentcodelAIIntroductionArticleIDt1001-9731(2006)01-0155Theseparationandrecoveryofmetalsfromaqueoussolutionareveryimportantinhydrometallurgyandwastetreatmentprocesses.Toavoidtheshortcomingsassociatedwiththeclassicliquid-liquide
6、xtractionu.theimmobileinterfacialmembrane-basedextractionhasbeenpaidmoreandmoreattention.Am0ngmembraneextractions,thehollowfibre-typemodulespresentthebestperformanceduetothehigherpackingdensity0fmembraneandthelowoperationcost.?.Mosteffortsonmembraneextractionwerefocusedonimprovingtheperformanceofthe
7、masstransferandinterpretingtheextractionmechanism.Inconventionalliquid-liquidmembraneextraction,theresistanceofextractionprocessoriginatedfromthediffusion,thentheoverallresistanceofextraction(1/K.)isthesummati0noftheaqueousboundarylayerresistance(1/k),membraneresistance(1/mk)andtheorganicboundary1ay
8、erresistance(1/mk.).0.k霄,km,k.aretheindividualaqueous,membraneandorganicmasstransferc0efficientsrespectively,misthecontributioncoefficientasformembraneextractionofmetalions,complexationreacti0nOCCUrontheinterfacebetweentheaqueousandmembrane.Sotheresistanceofcomplextionreactionshouldbeaddedtotheequat
9、ionoftheoverallresistance卜引.BesidesthemechanismofmembraneeXtracti0n,thestudy0ftheprocessingincludingextractionefficiencyisbecomingessentialforapplication.Inthiswork,themembraneextractionofCu.+inaqueoussolutionusingD2EHPAandPPhollowfibremembranewillbeinvestigated.TheeffectsoffeedsolutionpH,initialCC+
10、concentrationinorganicphase,flowvelocities0ftw0phasesandmembraneareasonextractionefficiencyofcopperionswerediscussed.Themechanismofextracti0nwasals0Pobedsimply?ItisexpectedthatapropermembraneextractionmethodshouldbeexploredfortheCC+seParationinaque0uss0luti0n.2Experimental2.1Reagentandsolutionprepar
11、ationTheextractantinthisworkwasD2EHPA.Commercia1ker0senewasusedasorganicsolvent.The0rganicsolutionisker0senesolutioncontaining1OD2EHPA(v/v).Theaqueousfeedwaspreparedbydiss0l,ringtheweightedamountofCuSOlinbuffersolutionsofHAcandNaAc.Alltheusedmateria1swere0fchemica1rea-gentgradeexceptthecommercialker
12、osene.Foundationitem:SupportedbyNationalBasicResearchProgramofChina(2003CB615705)Re睫Iveddater2005-03-05Modifieddater2005-06-14Corre啊dauthorlXUYou-yiBiographylU0D.an-y(1976一)?female?Hubeiprovince.doctor.majorin8;udyon.them锄b删ne眦t耐&Iandm咖bn鼬Iormatlon.ZUODan-ying,eta1.Extractingcopperionsfromaqueou
13、ssolutionusingD2EHPAinpolypropylenehollowfibremembrane1512.2Distributioncoefficientmeasurement50ml10D2EHPAsolutioninkerosenewasmixedwiththeaqueoussolutionwithvariouspHandknownCu2+concentration(CI).Aftervigorousshakingfor30min,themixturesweresettledfor24handseparatedin-totwophasesusingtheseperatoryfu
14、nne1.Thecopperionconcentrationsinaqueoussolution(c2)weremeasuredbyultravioletspectrometer(UV一1601).Thendistributioncoefficientcouldbecalculatedas:一下-L.1(1)2.3ExperimentapparatusandprocessesFig1showsaschematicoftheexperimentalsetup.TheextractionwasexecutedusingthePPhollowfibermembrane(HyfluxHualvMemb
15、raneTechnolo-gyCo.,Ltd.inHangzhouofChina)modulewhosecharacteristicsaredescribedinTable1.TheaqueoussolutioncontainingCu.+waspumpedthroughthelumenofthefiberandtheorganicsolutionthroughtheshellinasamedirection.Boththevolumesoftheaqueousandorganicsolutionweremaintained1000mlrespectivelydudngallexperimen
16、ts.Thevalveandpressuregaugeswereusedtocontroltheflowvelocity.Thepressureinaqueoussidewasmaintained0.1MPahigherthanthatinorganicsidetopreventtheorganicphasefrompenetratingintotheaqueousfeed.Fig1ExperimentalsetupforhollowfibermembraneTable1SpecificationsofmembranemoduleextractingCu.+usingacontactor(1)
17、Modulesize(2)FibereharaeteristicsLength(cm)20Innerdiameter(m)251Innerdiameter(cm)2Outerdiameter(m)303Averageporesize(m)0.1X0.O2Membraneporosity45Duringexperiments,thecopperconcentrationsweremeasuredatintervalsatvariousoperationconditions.ThecopperconcentrationsintheaqueoussolutionweretestedbyUV一1601
18、spectrometer.TheCu抖concentrationinorganicphasewasmeasuredbyatomicabsorptionspectrophotometerHITACHI180-50.3Resultsanddiscussion3.1DistributioncoefficientofD2EHPA-Cu-kerosenesystemTable2presenteddistributioncoefficientofCu抖inwithdifferentpH.ItisclearthatthedistributioncoefficientofCu抖dependedonpHofso
19、lutiongreatly.ThemaximumdistributioncoefficientwasobtainedatthepHof4.44,whichsuggestedthatextractingCu抖mustbemanipulatedoperatedataproperrangeofpH.Table2ThedistributioncoefficientofD2EHPA-Cu-kerosenesystempH2.893.184.O94.354.445.0O50755.79cJ0.8500.8940.8630.8920.8230.8000.8751.050c20.2370.1360.059O.
20、O190.0070.4450.7030.890,l2.595.5713.6345.95116.570.76O.24O.18ThecomplexationreactionofCu.+andD2EHPAintheextractionisexpressedasfollowsrt?.8:cuz+H2R2cuR2H+H+(2)二.2CuR2H+Cu(R2H)2+Cu.+(3)Infact,thecomplexationreactionofCat+andD2EHPAisaprocessofionsexchange,H+intheD2EHPAisreplacedbyCu抖.WhenpHis4.44.H+co
21、ncentrationatthatconditionfacilitatesthecomplexationreactionofCu抖andD2EHPA,andthedistributionreachesthemaximumvalue.152助能材斟2006年第1期(37)卷3.2Effectofoperationalconditionsonextractionefficiency3.2.1pHintheaqueoussolutionFig2showedtheextractionefficiencyvaryingwiththepHintheaqueousfeed.Theextractioneffi
22、ciencyreachedthemaximumwhenthePHwas4.44.TherelationshipbetweenthePHofaqueousfeedandextractionefficiencywasinagreementwiththerelationshipbetweenpHofaqueousfeedanddistributioncoefficient.Itwasdeducedthatthehigherdistributioncoefficientledtothehigherextractionefficiency.ThustheinitialaqueousfeedwithPHo
23、f4.44wasadoptedastheoperationconditionforalltheexperiments.3.2.2InitialCu2concentrationintheorganicphaseFig3showedthevariationofextractionefficiencywithCu抖concentrationintheorganicphase.WhenCu.concentrationswerelowerthan7.5g/L,extractionefficiencymaintainedover96.However,ifCu2concentrationswerehighe
24、rthan10g/L,theextractionefficiencydecreasedhastily.WhentheCu2concentra-tionsincreasedto1lg/L,theextractionefficiencyapproachedzero.TheaboveresultssuggestedthatwhenCu抖concentrationintheorganicphasewasveryhigh,theextractionefficiencystillmaintainedabove95.Thatistosay,theextractionsysteminthisworkwaspr
25、operforCu抖extractionfromaqueoussolution.Ontheotherhand,themolarratioof1lgcopperand100mlD2EHPAwascalculatedas1:2.whichwasthesametothatinthereactionofEq2and3.WhenCu2concentrationoftheorganicsolutioncontainingD2EHPAwas1lg/l,allextractantofD2EHPAhadreactedwithCu抖.Inotherwords,theorganicphasehadbeensatur
26、atedandcouldnotcombinemorecopperionsintheaqueoussolution.IfmoreCu.isextractedbythesamevolumeoforganicphase,theD2EHPAconcentrationmustbeincreased,orD2EHPAshouldberecoveredfromCu-D2EHPAcomplexes.Fig2EffectofpHinaqueousphaseonFigextractionefficiencytheorganicphaseonextractionefficiency3.2.3Flowvelociti
27、esofthetwophasesEffectofflowvelocitiesoftheaqueousandorganicphasesonextractionefficiencywasshowninFig4.Whentheflowvelocityoftheorganicphasewas20L/min,theextractionefficiencyatfourflowvelocities0ftheaqueouswashigherthan970A.Whentheflowvelocityoftheaqueousphasewas5L/min,theextractionefficiencyatfourfl
28、owvelocitiesofaqueousphasewashigherthan,980A.Then,neitherflowvelocityoftheaqueousphasenortheorganicphasehadanobviousinfluenceontheextractionefficiency.3.3MasstransferperformanceSupposingextractionwasmanipulatedatasequenceflowmodel,theoverallmasstransfercoefficientbasedontheaqueousphasewascalculateda
29、s1:一一去-n1+?n?n./AC,J(4)(5)wheredlistheinnerdiameteroffiber(m),wistheaqueousflowvelocity(m/s),Listhelengthofthefiber(cm),misdistributioncoefficient,dimensionless;Qandaretheaqueousandtheorganicfl0wvelociZUODan-ying,etal:ExtractingcopperionsfromaqueoussolutionusingD2EHPAinpolypropylenehollowfibre!塑ty,r
30、espectively(L/min),andaretheoverallvolumeoftheaqueousandtheorganicsolution,respectively(L),Cistheaqueousfeedconcentrationattimez(glm1),Cistheinitialaqueousfeedconcentration(g/m1),Gistheinitialorganicconcentration(g/m1).AccordingtotheEq4,Kvariedwithtime,asshowninFig5.TheresultssuggestedthatKwasremain
31、edunchangedininitialstage(25min).However,KdecreasedwithfurtherCu.concentrationloweringandtimeprolonging.TheseresultsdidnotfittheconventionalextractioninwhichKdidnotalterwithvaryingofCu2十concentration.Kwasaffectedbymanyfactor,thereforeitsnecessarytodiscusstherelationbetweenKandflowvelocitiesoftwophas
32、es.TherelationshipofKandflowvelocitieswasshowninFig6.AsitwasshowninFig6,flowvelocitiesoftwophaseshadweakeffectsonK.However,Kisproportionaltothe1/3poweroftheaqueousvelocityinconventionalliquid-liquidmembraneextractionthatwascontrolledbyresist-ancesofmembraneandaqueousboundarylayerc.2o.ThusCu.transfer
33、massmechanismofthisexperimentmightbeinconsistentwiththatofconventionalliquid-liquidmembraneextraction.Fo1w阳teI?min-Fig4EffectofflowvelocitiesoftwophasesonextractionefficiencyInpreviousstudiesonconventionalliquid-liquidmembraneextraction,mostauthorsconcludedthatthemasstransferperformanceandtheoverall
34、masstransfercoefficient(K)mainlyreliedonthediffusionsoftwophases.Thatistosay,themasstransferresistancesmainlyoriginatedfromtheaqueousboundarylayer.theorganieboundarylayerandmembraneitself.Ifthedistributioncoefficientisveryhighandmembraneishydrophobictheoverallresistanceofextraction(1/K)willbeequalto
35、theresistanceoftheaqueousboundarylayer(1/)approximatelyt.们.SoKisproportionaltothe1/3poweroftheaqueousvelocity.K62(鲁)(畿).whereistheinnerdiameteroffiber;tlistheaqueousflowvelocity;Listhelengthofthefiber,Disdiffusioncoefficientofsoluteintheaqueousphase.Infact,thecomplexationreactionattheinterfaceofthea
36、queousandmembranephasemaybeslow,sotheinterfacialreactionresistance(1/k)shouldbeintroducedinto1/K.Ontheotherhand,KhadnodirectrelationwithflowvelocitiesoftwophasesinviewofFig6inthiswork.Thentheresistanceofinterfacialcomplexationreactionwassupposedtocontroltheoverallmasstransfer,whichmeans:一KThereactio
37、nofCCandD2EHPAareexpressedasEq(2)and(3).toexplorethismechanism,thefluxJis:一4k(一+2一0(7)Usingthesteadystateapproximation(8)First,whenthecopperconcentrationishigh,J=忌-HzRzCu外(9)Thefluxisproportionaltothecopperconcentration.Theresistanceofinterfacialcomplexationreaction(1/)showninEq7wouldbeperfectedas:丢
38、=瓦1Second,whenthecopperconcentrationislowl(10)154助财斟2006年第1期(37)卷.,一.Thefluxisproportionaloft.hesquareofthecopperconcentration?edas(11)Nowtheinterfacia!resistanceiscalculat-1胜1H.一1f12一一FromEq10,itcanbefoundathighcopperconcentration,themasstransferresistanceandthemasstransfercoefficientwasindependent
39、ofCu抖,whileatlowcopperconcentration,themasstransferresistanceIncreasedwithCu2+reducing,themasstransfercoefficientdecreasedasCu2十reduced,ascalculatedbyEq12.Thisconclusionagreedwe11withtheresultinFig5.TherelationshipbetweenCu2十concentrationandKwouldbefurtherprovedbyKvariationwithinitialCu抖concentratio
40、nasshowninFig7.Kdidnotdependoninitialfeedconcentrationswhentheinitialfeedconcentrationswerehigh,whereasiftheinitialfeedconcentrationreduced,Kdecreased.Owingtothedominatingresistancewasindependentofthetwophasesvelocities,masstransfercoefficientandextractionefficiencyarenotproportionaltothe1/3poweroff
41、eedvelocityastheconventionalliquidliquidextraction.Theresultsabovesuggestedthatoursuppositionwasproper,namely,theoverallmasstransferresistancewascontrolledbytheinterfacialcomplexationreactionforcopperextractionwithD2EHPAinourtask.tlmlnFig6Masstransfercoefficientversusflowvelocities4ConclusionFigpper
42、concentrationonmasstransfercoefficientTheextractionofcopperwithkerosenesolutionsofD2EHPAwasperformedinPPhollowfibermembranemodulesinthiswork.Extractionefficiencydependedonnotflowvelocities,butthepHofthefeedsolutionandinitialcopperconcentrationsoftheorganicphase.Theresultssuggestedthattheoverallmasst
43、ransferresistancewasgovernedbytheinterfacialreaction.ThemasstransferresistanceandthemasstransfercoefficientwasindependentofCu抖onhighcoppercationsconcentrations,whereasatlowcoppercationsconcentration,themasstransferresistanceincreasedasCu.concentrationreducedandthemasstransfercoefficientdecreasedasCu
44、gconcentrationreduced.Referenees:E13233343536373839310113123PrasadR,SirkarKK.J.SepSciTech,1987,22(2&3)l619640.KiamA,BhaveRR,SirkarKK.J.JMembrSci,1984,2O:125-145.KimBM.J.JMemhrSci,1984,21:519.DellaNancyA,DahuronL,CusslerEL.J.JMembrSci,1986,20:309-319.PrasadR,SirkraKK.J.AIChEJ,1988,34(2):177-188.M
45、iyakeY,MastsuyamaH,NishidaM,eta1.KineticsandMechanismofMetaIExtractionwithAcidicOrganophosphorusEx-tractants,PartI.M3.H.ydrometallurgylExtractionRateLimitedbyDiffusionProcess,1990.19-35.GeistA,PlucinskiP,NitschW.口.SoIExtrIonExchange,2000,18:493-515.AlexanderPR,CallahanRW.J.JMembrSci,1987,35:57-71.Ju
46、angRS,HuangHL.J.JMembrSci,2003,213:125-135.JuangRS,HuangHL.J.JMembrSci,2002,208l3138.YangZF,GuhaAK,SirkarKK.J.IndEngChemRes,1996,35l13831394.JuangRS,ChenJD,HuanHC.口.JMembrSci,2000,165l5973.(下转第159页).Eo-o1.,.二J3-o1.,wuaI卜血I1g,etal:Influemeoftheprocessingconditionson些14ConclusionsLiMnzOthinfilmswerepr
47、eparedbysolutiondepositionthroughspin-coatingtechnique.Alotoffactorsthatmightaffectthemorphologyofthethinfilmwereexamined.Theresultsshowthatthesolvent,solutionconcentration,spinrate,spintime,heatingrate,decomposingtemperatureandtimeannealingtemperatureandannealingtimehavegreatinfluenceonthemicrostructureofLiMnzO4thinfilms.TheoptimalprocessingconditionsarethattheconcentrationofLiMnzoprecursorsolutionis0.2mol/L,spinrateandtimeare300Or/minand30s,Deco?