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Removal (2)

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Removal (2)Remova

    Removal

ChineseChemicalLettersVo1.16,No.5,PP701704,2005

    ;http://www.imm.ac.cn/joumal/cc1.html

    ;7()l

    ;RemovalofSafraninefromAqueousSolutionbyUsingAdsorptive

    ;BubbleSeparationTechniques

    ;ChungShinLU.ChiingChangCHEN,YaPingSU,KungTungCHEN

    ;Del:Iartmentofgeneraleducation,NationalTaichungNursingCollege,Taichung,Taiwan403 ;2Departmentofgeneraleducation,

    ;MingHsinUniversityofScienceandTechnology.

    ;HsinChu,Taiwan304

    ;Abstract:Safranine,acationicdye,wasremovedfromsyntheticwastewaterbyionflotation. ;Over98%ofsafraninewasremovedfromthesolutionin10min.Astoichiometricamountof ;surfactantr1molofsurfactanttolmolofdye)wasfoundtobemosteriectivetorsatranine ;remova1.Theseparationefnciencyofsafraninedecreasedwithincreasingconcentrationof ;NaN01.SafraninewasalsoremovedbyadsorbingcolloidflotationtechniqueusingFe(OH)3as ;thecoagulantSodiumlaurylsulfatewasusedasthecollector,andover97%ofsail’aninewas

    ;removedin5min.Theseparationefficiencydecreasedwithincreasingionicstrengthofthe ;solution.ThedeleteriouseffectofneutralsaltwascompensatedsomewhatwiththeaidofAlas

    ;theactivator.Bothionflotationandadsorbingcolloidflotationmaybeapplicableintheremoval ;ofsafraninefromwastewater.

    ;Keywords:Safranine,ionflotation,adsorbingcolloidflotation

    ;Ionflotationtechniqueisaprocessinwhichanionicsolute,calledthecolligend,is ;removedfromaqueoussolutionbyaddingsurfaceactivecollectorionofacharge

    ;oppositetothatonthecolligend,andthenbubblingtheairthroughthesolution.When ;thebubblesreachthesuffaceoftheaqueoussolution.afoamisformedinwhichasolid ;phaseisdeposited.Theapplicabilityofionflotationasatechniquetotreatdyesin ;wastewaterhasbeeninvestigatedfordyesofonlytwokindsdirectblue,andauramine.

    ;Theremovalofsafraninefromanaqueoussolutionbyionflotationwasstudied. ;Becausesafraninecancausesomeenvironmentalproblem,thesearchofasimpleand ;effectiveremovalmethodisnecessary.

    ;TheadsorbingcolloidflotationtechniquehasbeenappliedinremovingVariOUS ;inorganicspeciesfromaqueoussolutions.Thistechniqueinvolvestheadditionofa ;coagulantfferricoralumnitrate)toproduceafloc.Thedissolvedinorganicspeciesare ;adsorbedontotheflocparticleand/orcoprecipitatedwithit.Asurfactantisthenadded, ;adsorbsontotheflocparticle,andrendersithydrophobic.Onbubblingairthroughthe ;solution.theflocisadsorbedontherisingbubbleandcarriedoutfromthesolutionbythe ;foam.InthisPaDerwealsoattemptedtoremovesafraninebyadsorbingcolloid ;flotation.

    ;E—mail’ccchen@ntcnc.edu.tw

;

    ;702

    ;Experimental

    ;ChungShinLUetal

    ;Theapparatusforionflotationandadsorbingcolloidflotationwassimilartothat ;describedearlier..

    ;Fortheionflotationruns,sodiumlaurylsulfate(NLS)wasaddedto ;thesamplesolutiontoformthedyesurfactantcomplex,thepHofthesolutionwas

    ;adjusted,thesolutionwaspouredintotheseparationcolumn,andthetimerwasstarted. ;Therateofairflowwasadjustedbeforethesamplesolutionwaspouredintothecolumn. ;Fortheadsorbingcolloidflotationruns,Fe(OH)wasaddedtothesamplesolution,and ;thepHwasadjustedtoproducethefloc.Safraninewasadsorbedonorcoprecipitated ;withthefloc.NLSwasaddedtorendertheflochydrophobic,andthesolutionwasthen ;pouredintothecolumnforseparation.A11runsweremadewith250mLoftestsolution ;thatcontained7.1×10mo1/Lsafranine.Theconcentrationsofdyeinthesample ;solutionsweredeterminedusingaUV/Visspectrometer(PerkinElmerLambda25). ;ResultsandDiscussion

    ;TheeflfectofsurfactantconcentrationontheionflotationofsafranineisshowninFigure ;1.Itwasfoundthatal:lmoleratioofsuffactanttodyeisenoughforaneffective ;separationwithapproximately98.3%removalinl0min.A1argeexcessofsurfactant ;dosageresultedjnalowerremovaleciency:thisjspresumablyduetothecompetition ;forthebubblesurfacebytheexcesssurfactantionwiththedyesurfactantcomplex.A

    ;similareffectwasobservedonthesolventsublationofmagentaNLS.directredHTA.

    ;acidredHTA.methylviolet—DBS”andionflotationofdirectblue.Thisfindingwas

    ;quitedifierentfromthesolventsublationresultsformethyleneblueandmethylorange ;studiedbyWilsoneta1.”,whofoundthattherateofremovalofmethyleneblueand

    ;methylorangeincreasedwithincreasing

    ;excessofthestoichiometricamount.

    ;concentrationofsurfactant,whenitwasinmuch

    ;Thiscontradictionisprobablyduetothe

    ;differenceintheformationconstantofthedifferentsurfactantdyecomplexesandalso

    ;duetothedifferenceinthemoleratioofthedyeandsurfactantofthecomplexes. ;Figure1EffectofNLSdoseonionflotationFigure2EffectofNaNO3onionflotation ;ofsafranineofsafranine

    ;00515225335

    ;NLS/Dve

    ;00050104

    ;NaNO(moI/L)

    ;pH=6,rateofairflowwas180mL/min,MolarratioofNLStodyewas1,pH=6,rate ;durationofairflowwas15,10,5and3minofairflowwas180mL/min,durationofair ;fromtopdown.flowwas15,10,5and3minfromtopdown.

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    ;RemovalofSafraninefromAqueousSolution703

    ;Figure3EffectofpHonadsorbingcolloidFigure4EffectofNLSonadsorbingcolloid

    ;flotationofSafl’anineflotationofsaIranine

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    ;pH

    ;[Fe1=1.8~10mol/L.[NLS]=3.5xl0mol/L, ;rateofairflowwas12OmL/min.durationofair

    ;flowwas20,15,10,5and3rainfromtopdown

    ;Figure5EffectofNaNO3onadsorbing

    ;colloidflotationofsaffanine ;110

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    ;NaNO(mol/L)

    ;Fe”1:1.8x10.mol/L,pH=5,rateofarflow--= ;50mUmin,fNLS]=2.1x10mo,durationof ;airflowwas20,15,10,5and3minfromtop

    ;down.

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;7()

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    ;1.11.42.123.5

    ;NLSf10moI/L)

    ;[Fe1=1.8xl0mol/L,pH=5,rateofairflow

    ;was12OrTmin.durationofairflowwas20.

    ;15,10,5and3rainfromtopdown.

    ;Figure6EffectofA1onadsorbingcolloid

    ;flotationofsafranine

    ;l1O

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    ;=70

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    ;O3.87.615.230.4

    ;A1f10mol/L,

    ;Fe:1.8X10mol/L,pH=5,rateofair

    ;flow=50mL/min,{NLS1=2.1×10mol/L,

    ;NaNO3]=0.4mol/L,durationofairflowwas

    ;20,15,10,5and3minfromtopdown.

    ;TheeflfectofneutralsaltfNaN01)ontherateofremovalofsafranine.NLScomplex ;byionflotationisshowninFigure2.Theseparationefficiencydecreasedsomewhat ;withtheadditionofneutralsalt,presumablyduetothecompetitionforcollectorbetween ;thecolligendandtheionsofsalt.Wilsoneta1.”.alsoobservedtheinhibitingeffect

    ;ofneutralsaltsonthesolventsublationofbothmethylenebluetetradecylsulfateand

    ;methylorangeHTAdyesurfactantcomplexes.

    ;Anotherseriesofexperimentswereperlormedusingtheadsorbingcolloidflotation ;techniquetoremovesaffanineffomaqueoussolution.TheeflfectofpHonthe ;adsorbingcolloidflotationofsaffaninewithFe(OH)flocisshowninFigure3. ;Sodiumlaurylsulfatewasusedasthecollectorandfrother.Itwasfoundthattherateof ;removalwasrapidatapHrangeof57:over91%ofsaffaninewasremovedinl5min.

    ;Therateofseparationandseparationemciencydecreasedsignificantly.ifthepHofthe ;solutionwastoolow,probablyduetoincompleteformationofFerOH)1npcatlowerpH. ;Theeflfectofsurfactantdosageontheseparationefficiencyofadsorbingcolloid ;flotationofsaffanineisshowninFigure4.NLSconcentrationat2.1×l0moI/Lwas ;

    ;704ChungShinLUetal

    ;sufficientforaneffectiveseparation.Atagreaterconcentrationofsurfactant(3.5x10 ;tool/L),therateofseparationofsaffanineissmaller,presumablyduetothecompetition ;0fthebubblesurfacebytheexcesssurfactantionwiththeFe(OH)3floc.

    ;TheeffectofNaN01ontheseparationefficiencyofadsorbingcolloidfotationof ;safranineisshowninFigure5.Theseparationefficiencydecreasedwithincreasing ;ionicstrengthofthesolution,presumablyduetoadecreaseofthesurfacepotentialofthe ;flocbytheadsorptionoftheanion(nitrateion)inthesolution.suchthatthesufface ;potentialoftheflocwasnolongerpositiveenoughforasufficientamountofanionic ;surfactanttobeadsorbedItwasfoundthatonly68.5%ofsafraninewasremovedinl() ;rainfromasolutioncontaining0.4mol/L0fNaNO3.

    ;WeattemptedtouseA1+astheactivatorsfortheremovalofsaffanineffomsolution ;containing0.4mol0fNaNObyadsorbingcolloidflotation.Theresultsareshownin ;Figure6Efiectiveseparationwith94.7%removalofsaffaninewasachievedinl0rain ;when3.8×10.mol/LofA1wasadded.

    ;TheeffectofAl”astheactivatoris

    ;presumablyduetotheincreaseofthesurfacepotentialoftheflocbytheadsorptionof ;A1?speciesontheFe(OH)3floc(orbyformingamixedprecipitate),suchthata ;sufficientnegativelychargedsurfactant(NLS)canbeadsorbedontothesurfaceofthe ;floc.thusrenderthesurfaceoftheflochydrophobic.Thisresultsinaneffective ;separation.

    ;Conclusion

    ;Safraninewasremovedeffectivelyfromsyntheticwastewaterbyionflotation;over98% ;ofsafraninewasremovedfromthesolutioninl0min.Theseparationefficiency ;increasedwithincreasingrateofairflowanddecreasedwithincreasingconcentrationof ;NaNO.AdsorbingcolloidflotationofsaffaninewithFe(OH)flocandNLSis ;eriectivewith97%removalofsafraninein5min.Thedeleteriouseffectofneutralsalt ;ontheadsorbingcolloidflotationofsaffanineiscompensatedbyuseofAl”asactivator.

    ;whichincreasesthesurfacepotentialoftheflocasaresultoftheadsorptionofAl ;species.

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    ;A.N.Clarke,D.J.Wilson,Sep.Pur{fiMethods,1978,7,55.

    ;R.Lemlich.AdsorptiveBubbleSeparationTechniques,Academic,NewYork,1972. ;C.S.Lu,S.D.Huang,Sep.Sci.Techno1.,1992.27(131,l733.

    ;GL.Sheu,S.DHuang,Sep.Sci.Techno1.,1987.22,2253.

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    ;J.Lw0mack,J.C.Lichter,D.JWilson,Sep.Sci.Technof.,1982.7(71,897 ;Received18February,2004,Revised22June,2004

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