厦大英文报告

Reporter:ChenYuehaoMajor:EnvironmentalEngineeringResearchsupervisor:OuyangTong1ContentsIntroductionMaterialsandMethodsResultsandDiscussionConclusions2FirstPartIntroduction3MethylBlue（1/4）DyeWastewater4MethylBlueChitosan（2/5）5ChitosanChitosanisalinearpolysaccharide,whichismadebydeacetylationofchitin.Andithasanumberofcommercialandpossiblebiomedicalapplicationsduetoitsbiodegradability,biocompatibilityandrenewability.AdvantagesAccessibilityHigheffectivityNoharmfulby-productHighadsorptioncapacityMagneticChitosan（3/5）6Itisdifficulttobeseparatedandrecoveredexceptbyhighspeedcentrifugationandfilter.powderychitosanMagneticChitosan(MC):attacheschitosantothesurfaceofmagneticparticles.Grapheneoxide（4/5）Grapheneoxidehastheadvantagesoflargetheoreticalsurfacearea,highmechanicalstrength,richfunctionalgroups,non-toxicandinexpensive.7grapheneoxideExperimentalobjectives（5/5）8（1）Exploreandpreparemagneticchitosan-grapheneoxide(MCGO)compositebio-adsorbentwithhigheradsorptioncapacityandexcellentseparationproperties.（2）Methylblue(MB)withlargeandcomplicatedstructureswasselectedasmodelpollutanttoevaluatedtheadsorptioncharacteristicsofMCGOunderlaboratoryconditions.SecondPartMaterialsandMethodsPreparationofMCandMCGO9AdsorptionexperimentsPreparationofMCandMCGO（1/3）FeCl2·4H2OandFeCl3·6H2Oareusedtomakemagneticparticles.10Addmagneticparticlesandglutaraldehydetochitosanaceticacidsolution.WashtheprecipitateuntilpHwasabout7,anddryit.UsethemodifiedHummersmethodtoprepareGO,andactivatethecarboxylgroupsofGOMCAdd0.1gMCtotheactivatedGOsolution.Afterultrasonicdispersionfor10min,themixedsolutionwasstirredfor2h.MCGOWashtheprecipitateuntilpHwasabout7,anddryitAdsorptionexperiments（2/3）（1）AllbatchadsorptionexperimentswereperformedonaSHA-Cshakerwithashakerspeedof150rpmuntilthesystemreachedequilibrium.11（2）Typically,a25mLsolutionofknownMBconcentrationand0.015gofMCGOwereaddedinto100mLglassflasksandthenshookunder30±0.2℃.（3）Atthecompletionofpresettimeintervals,thebio-adsorbentswerecollectedbytheaidofamagnet.Adsorptionexperiments（3/3）ResidualMBconcentrationinsupernatantwasmeasuredbyusingaspectrophotometer.TheAbsorbanceismaxMB=610nm.12Q:adsorptionquantity;E:adsorptionrate;C0:theinitialconcentration;Ce:theequilibriumconcentration;V:thevolumeofMBsolution,inliters;W:theweightoftheMCGOused,ingrams.ThirdPartResultsandDiscussion13SEM（1/10）Fig.1.SEMimagesofGO(A)andMCGO(B).GO：thesheet-likestructurewithlargethickness,smoothsurface,andwrinklededge.14TheMCGOhasamuchroughersurface,revealingthatmanysmallmagneticchitosanhadbeenassembledonthesurfaceofGOlayerswithahighdensity.TheBETsurfacearea:392.5m2/g;Theporevolume:0.3852cm3/g;Theaverageoftheporesizedistributionis2.587nm.Theaverageparticlesizeis200nm.mesoporousmaterialFTIR（2/10）Fig.2.IRspectraofGO(A)andMCGO(B).15C-O-CC-OHC-CC-O(COOH)O-HFe3O4C-O(NHCO)XRD（3/10）Fig.3.XRDpatternofpureFe3O4(A),magneticchitosan(B)andMCGO(C).TheXRDanalysisresultsofpureFe3O4,magneticchitosanandMCGOweremostlycoincident.Itindicatestheexistenceofironoxideparticles(Fe3O4),whichhasmagneticpropertiesandcanbeusedforthemagneticseparation.16pH（4/10）Fig.4.EffectofpHontheadsorptioncapacity(initialconcentration,200mg/L;temperature,303K;contacttime,60min).Blackpoints:QeversusinitialpHvalues;redpoints:equilibriumpHvaluesversusinitialpHvalues.TheoptimumpHrangeforMBadsorptionontoMCGObio-adsorbentsis4.5–6.5.17Adsorptionkinetics（5/10）18Thepseudo-first-orderkineticmodelQe:adsorptionquantityatequilibrium,inmg/g;Qt:adsorptionquantityattimet`,inmg/g;K1:therateconstantofadsorption(min−1);t:time,inmin.Thepseudo-second-orderkineticmodelAdsorptionkinetics（6/10）Fig.5.Pseudo-first-orderkineticplotsfortheadsorptionofMB(A),andpseudo-second-orderkineticsforadsorptionofMB(B)(pH5.3,temperature:303K).19Table1AdsorptionkineticparametersofMBontoMCGO.Adsorptionisotherm（7/10）Fig.6.ThelineardependenceofCe/QeonCe(pH,5.3;temperature,303K;contacttime,60min).Theadsorptionprocessismainlymonolayeradsorptiononthesurface.20TheLangmuiradsorptionisothermmodelTemperature（8/10）Fig.7.Van’tHoffplotsfortheadsorptionofMBontoMCGOThenegativevalueofΔHshowsexothermicnatureofadsorptionprocess.TheadsorptionwasfavoredatlowertemperatureandMBmoleculeswereorderlyadsorbedonthesurfaceofMCGO.ThenegativevalueofΔGindicatesthattheadsorptionreactionwasspontaneousat303,313and323K.21Table2Thermodynamicparametersatdifferenttemperatures.Van’tHoffequationDesorptionexperiments（9/10）Fig.8.EffectofrecyclingadsorbentsonMBadsorption(pH,5.3;initialconcentration,200mg/L;temperature,303K;contacttime,60min).The0.5mol/LNaOHistheoptimumeluent.22Desorptionpercentages/%HCl5.1NaOH95.1H2O1.4Table3ThedesorptionpercentagesofHCl,NaOHandH2O(Concentration,0.5mol/L).最大吸附量（10/10）Table4MaximumadsorptioncapacitiesfortheadsorptionofMBontovariousadsorbents.23FourthpartConclusions24Conclusions（1/1）（1）PreparetheMCGOcompositebio-adsorbentwithhigheradsorptioncapacityandexcellentseparationpropertiessuccessfully.（2）TheadsorptionofMBonMCGOwasstronglydependonpHandionicstrength,indicatinganionexchangemechanism.（3）Theadsorptionfollowedpseudo-second-orderkinetics,and