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:025322468(2000)20220139206:X791:AFentonPVA(,310027):FentonPVA,0.75L.,Fenton,Fenton.,0.5h,90%.,Fe(),,Fenton.::Fenton;;;Advancedoxidationofpolyvinyl2alcoholbythephoto2fentonreactionLEILecheng(DepartmentofEnvironmentalScienceandEngineering,ZhejiangUniversity,Hangzhou310027)Abstract:Theeffectivedegradationofpolyvinyl2alcoholwasachievedbytheapplicationofphoto2Fentonreaction.Thisadvancedoxidationprocesswasstudiedinabatchreactor(V=0.75L)usingamercurymediumpressurelampasthelightsource.Effectiveoxidationwasobservedwhenemployinglowiron()concentrationsandastoichiometricamountofH2O2.ExperimentalresultsshowedthattheremovalrateofDOCcanberemarkablyenhancedbyemployingPhoto2FentoncomparedtoclassicalFentonreaction.TheremovalrateofDOCwasaffectedbytemperature,suitablecarriergas,dosageofhydrogenperoxideandironadded.Theexperimentaldatasupportedanadvancedoxidationmech2anismoccurringwithintheperformediron()/iron()2PVAsupermolecule.IndistinctcontrasttotheclassicparadigmoftheFentonreaction,thehydroxylperoxideradicalasreactiveintermediatewasnotfoundfortheforma2tion.CO2wasreleaseddirectlyfromthesupermacromolecule;lowmolecularweightintermediateswerenotfounddur2ingthePVAdegradation.Keywords:advancedoxidation;photo2fentonreaction;wastewatertreatment:1998207209;:1999202222:(1963),,(),.,,.PVA(),.PVA,,PVA[1].,PVA,,[2].,(AOPs)[3,4].,TiO2,OH,[3,5].,Fenton,Fenton[611],[12].20220003ACTASCIENTIAECIRCUMSTANTIAEVol.20,No.2Mar.,2000FentonPVA,Fenton,.2,1.(016L)HPK2125(0115L).015LPVA200mg(C)/L,pH410.(Masterflex752118200).40,,,.,011mol/L1Fig.1Photochemicalbatchreactor,012m.(DOC)DC2190;UV/HP25800().H2O2[13].[14].PVA,HP21090,HPTSK2AC/4000SWGPC,011mol/LNa2SO4Na2HPO4(pH=7).LiChrosphor2100RP/18,0105mol/L/H3PO4(pH=710,95%)(5%).2211UV2PVAUV11PVA21PVA+Fe2+31PVA+Fe3+41Fe2+51Fe3+Fig.2UV2spectraoforiginalPVA,ironandthemixturewithPVAPVAUV2.Fe2+PVAPVAFe2+UV,PVAFe3+UV,200-400nmUVFe3+,PVAFe3+UV.3FentonFentonPVA.,PVA49000,1.6710-2mol/L(DOC),(DOC)3.3310-2mol/L,Fe2+1/20(1.6710-3mol/L),pH4,40,.,PVA200400nm,Fenton,H2O2,041203PVAFentonFentonUV0111Fenton(10min)21Fenton(20min)31Fenton(30min)41Fenton(10min)51Fenton(20min)61Fenton(30min)Fig.3UV2spectraduringtheFentonandphoto2fentondegradationofPVA,understandardconditions.,260400nm,,200260nm,.21221211PVA3PVAFentonFenton,,4.15000,49000,100000PVA,FentonFentonDOC.20min,1.1PVATable1FirstorderreactionrateconstantsofPVAdegradationPVAK(Fenton),s-1K(Fenton),s-1150002.7210-41.4010-3490002.4110-41.4210-34PVAFentonFenton11FentonMW15000021FentonMW4900031FentonMW10000041FentonMW15000051Fenton4900061Fenton100000Fig.4PVAdegradationbyFentonandphotoFentonreactionwithdiffer2entPVApolymers1000002.5210-41.4610-3,PVA.4,FentonFenton.2.2.2DOC5.Fe2+,.,DOC,Fenton,DOC,Fenton,DOC.,,PVA.UVPVA.2.2.3DOC6.H2O2.H2O2,DOC.,DOC.,PVA.H2O2;Fe()1412:FentonPVA5PVAFen2tonFig.5Theeffectofiron()concentrationsonPVAdegradationbyphotoFentonreactionunderstandardconditionsFe().2.2.4FentonPVA,7.1/20,H2O2,.Fenton.Fenton10min,DOC20%.50%,2hDOC61%,72%.PVA,FentonR,R[13].6PVAFentonFig.6TheeffectofH2O2concentrationonPVAdegradationbyphotoFentonre2action,understandardconditions7PVAFentonFig.7EffectofcarriergasonPVAdegrada2tionbyphotoFentonreaction2.3FentonFe()Fe()[1518],OH.Fe3+3aq+H2OhFe3+aq+OH+H+(1)Fe()Fe(),Fe(),,510nm8.(Fe()),2.(Fe())=dn/dtpa(2),dn/dt:(mol/Ls-1);Pa:(enstein/(Ls-1)).241208()510nmFig.8LightabsorbanceofthevariousFe3+mixturesunder510nmirradiation2Fe()Fe()Table2Quantumyieldsonvariousreactionsystems(photon/s)1.14Fe3+/PVA/UV,t=0min0.94Fe3+/PVA/UV,t=30min0.12Fe3+/H2O/UV0.33,PVA,Fe()PVAFe()0.94,Fe()0.33,PVAFe(),Fe()Fe()PVA.HPLCPVA,,3PVAFentonFentonHPLCGPC,GPCPVA,.PVAPVA,CO2,.OH,(3),Fenton(1).Fe3+aq+PVA=0194Fe2+aq+PVA3(3)8,FentonPVA0.5h,PVA0.1mol/LNa2SO3H2O2,0.12;1hPVA.10%DOC,Fe()Fe().9Fig.9H2O2exhaustionintermsofvariousex2perimentalconditions,H2O2FentonHO2,Fe().Fe()H2O2,Fenton.Fe2+H2O2,H2O2Fe2+,H2O2,9.,,FentonH2O2Fenton.Fe()H2O2Fe().Fe3+3aq+H2O2hFe2+aq+HO32(4),FentonFenton,Fe3+aqH2O23412:FentonPVAFe().3Fenton,FentonFenton.,0.5h,90%.Fenton.DOCPVA.,FentonFe3+aqH2O2Fe().PVAPVA,CO2,PVA.:[1]SchluterK,TextileAuxiliaries2SizingAgents[J].UllmannsEncyclopediaofIndustrialChemistry,1995,A26:244253[2]ZiemannA[J].ForumStaedte2Hygiene,1994,4:214217[3]LegriniO,OliverosE,BraunAM.Photochemicalprocessesforwatertrantment[J].ChemRev,1993,93:671698[4]OllisDF,HAE(Ed).ProceedingsonPhotocatalyticPurificationandTreatmentofWaterandAir[C].Elsevier,Amster2dam.1993[5]BuxtonGVC,GreenstockLW,HelmanP,etal.[J].JPhysChemRefData,1988,17:513886[6]Lipczynska2KochanyE.Degradationofaqueousnitrophenolsandnitrobenzenebymeansofthefentanreaction[J].Chemo2sphere,1991,22:529536[7]RuppertG,BauerR,HeislerG.Thephoto2fentonreactionaneffectivephotochemicalwaste2waterteatmentprocess[J].JPhotochemPhotobiol,A:Chem,1993,73:7578[8]AndrianirinahariveloS,MailhotG,BolteM.Photodegradationoforganicpollutansinducedbycomplexationwithtransitionmetals(Fe3+andCu2+)presentinnaturalwater[J].SolarEnergyMaterialsandSolarCells,1995,38:459474[9]Safarzadeh2AmiriJ,BoltonRA,CaterSR[J].JAdvOxidTechnol,1996,1:1826[10]PignatelloJJ,ChapaG.Degradati