Fe3或Fe2均相催化H2O2生成羟基自由基的规律高迎新副本

Fe3+Fe2+H2O21,2,2,2＊,1(1.,　100871;2.,　100085):-(ESR)FentonFenton.,FentonFentonH2O2Fe3+Fe2+,FentonFenton.FentonpH2.5～3.5,FentonpH2.8～3.0.,FentonFenton.,.:Fenton;Fenton;;;:X52　:A　:0250-3301(2006)02-0305-05:2005-01-27;:2005-03-27:(20207013);(863)(2002AA601310):(1968～),,,.＊,E-mail:[e-mail]dicalProductionRatesinH2O2SolutionunderHomogeneousCatalysisofFe3+orFe2+GAOYing-xin1,2,ZHANGYu2,YANGMin2,HUJian-yin1(1.CollegeofEnvironmentalSciencesofPekingUniversity,Beijing100871,China;2.StateKeyLaboratoryofEnvironmentalAquaticChemistry,ResearchCenterforEco-EnvironmentalScience,ChineseAcademyofSciences,Beijing100085,China)Abstract:Theproductionof·OHradicalswasinvestigatedbyusingtheelectronspinresonance(ESR)methodwith5,5-dimethyl-1-1pyrroline-1-oxide(DMPO)asspintrapreagent.ESRsignalscomposedof4lineswitha1∶2∶2∶1intensityratioindicatedtheformationof·OHradicalsintheFenton-likereaction.Forbothsystems,theproductionratesofhydroxylradicalsintheinitialstagewereconsiderablyhigh,andincreasedwithincreasingconcentrationsofH2O2andFe2+orFe3+.However,theradicalproductionrateinFentonreactionsystemwasmarkedlyhigherthanthatinFenton-likereactionundersimilardosingconditions.Thedifferencesofradicalproductionratesbetweenthereactionsystemsremainedevenintheslowreactionstage.TheoptimumpHrangesoftheproductionof·OHradicalsinFentonprocessandFenton-likeprocesswere2.5～3.5and2.8～3.0respectively.TheaboveresultsdemonstratethattheFentonsystemandFenton-likesystemarepossiblybasedondifferentreactionmechanisms.Keywords:Fentonreaction;Fenton-likereaction;electronspinresonance(ESR);spintrapping;hydroxylradical　　FentonFentonH2O2,[1～4].,Fenton,Fenton.,,FentonFe2+Fe3+,Fenton[2].,2[4～7].,.:(ElectronSpinResonance,ESR)-、/、.,、[8～10].、(·OH)、(HO2·)(·O-2).,(),,,ESR.,phenyl-tert-butylnitrone(PBN)5,5-dimethyl-1-pyrroline-1-oxide(DMPO)[8,11].DMPO1:N+O-DMPO+·OHNO·DMPO-OHOH(1)ESRFenton27220062　　　　　　ENVIRONMENTALSCIENCEVol.27,No.2Feb.,2006DOI:10.13227/j.hjkx.2006.02.021Fenton,,.1　1.1　(FeSO4·7H2O)、(Fe2(SO4)3·xH2O)、、(30%).DMPOFisher,;(MilliQwater;TOC≤0.2mg/L;18MΨ·cm).DMPO:DMPOKH2PO4-NaOH(PBS),、.KH2PO4-NaOH(PBS):pH.、[12].:VarianE-109;pH(TOA,).1.2　(1)pH　50μLpHDMPO,50μLH2O2,ESR.(2)DMPO　50μLDMPO,50μLH2O2,.(3)H2O2,Fe2+,Fe3+　pHDMPO50μLH2O2,Fe2+,Fe3+,.(4)Fenton、Fenton　Fenton、Fenton,pH,100μL50μLDMPO.1.3　ESR.:0.3250T;2×10-2T;:128s;4min;20mW;(γ)9.120036GHz;10-4T.g2.0028;(2)ESR:0.32535T.H=hνgβ(2)　　(2):h,6.6262×10-34J·s;β,9.2741×10-24J/T2　2.1　FentonESRFenton.,,Fenton[5,7].,Fenton.1Fenton(ESRg=2.0028,aN=14.9×10-4T,aH=2.74×10-4T).1,Fenton1∶2∶2∶14,DMPO-OH[11].,Fenton,DMPO-OH.[Fe3+]0=0.25mmol/L;H2O2=10mmol/L;DMPO=150mmol/L;PBSpH:7.41　FentonDMPO-OHFig.1　ChromatographofDMPO-OHinFenton-likeprocess2.2　2PBSpH.2,pH5.5～7.4,pHESR.pH,DMPO.,FentonDMPOpH7.4.3DMPO.3,DMPO0～150mmol/L,ESR.DMPO306　　　　　　27,DMPO.FentonDMPO150mmol/L.[Fe3+]0=0.25mmol/L;[H2O2]0=5mmol/L;DMPO=150mmol/L2　pH·OHFig.2　EffectofpHon·OHanalysis[Fe3+]0=0.25mmol/L;[H2O2]0=5mmol/L;pH=7.4PBS3　DMPO·OHFig.3　EffectofDMPOon·OHanalysis2.3　·OH4H2O2FentonFenton.4,H2O2,FentonFenton·OHH2O2.Fenton,H2O212.5mmol/L,H2O2.H2O2,.Fenton,Fenton.H2O2.H2O2,FentonFenton.,H2O2,.Fe2+(Fe3+):0.25mmol/L;DMPO:150mmol/L;pH:7.4PBS4　H2O2·OHFig.4　EffectofH2O2on·OHformation5Fe2+Fe3+2·OH.5,FentonFentonFe2+Fe3+.,FentonFenton.Fenton,Fe2+0.5mmol/L,Fe2+.Fe2+,.,Fe3+0.4mmol/L,FentonFe3+.H2O2:5mmol/L;DMPO:150mmol/L;pH:7.4PBS5　Fe2+Fe3+·OHFig.5　EffectofFe2+orFe3+on·OHformationFenton,DMPO:H2O2+Fe2+※Fe3++HO-+HO·k1=63.0L/(mol·s)(3)DMPO+·OH※DMPO-OH3072　　　　　　k2=3.4×109L/(mol·s)(4)HO·+Fe2+※Fe3++HO-k3=3.0×108L/(mol·s)(5)HO·+H2O2※HO2·+H2Ok4=3.3×107L/(mol·s)(6)　　:d[·OH]dt=k1[H2O2][Fe2+]-k2[·OH][B]-k3[H2O2][·OH]-k4[·OH][Fe2+](7)　　B:DMPO.,(7):d[·OH]dt=0(7):[·OH]=k1[H2O2][Fe2+]k2[B]+k3[H2O2]+k4[Fe2+](8)DMPO:-d[B]dt=k2[B][·OH](9)(8)(9),:-d[B]dt=k2[B]k1[H2O2][F2+]k2[B]+k3[H2O2]+k4[Fe2+](10)　　,(10)(11)(12):[B]0[H2O2]0(-d[B]/dt)0=k4k1k2+k2[B]0+k3[H2O2]0k1k2[Fe2+]0(11)[B]0[Fe2+]0(-d[B]/dt)0=k3k1k2+k2[B]0+k4[Fe2+]0k1k2[H2O2]0(12)　　,DMPO-OHH2O2Fe2+(11)(12).DMPO-OH[H2O2]0[Fe2+]0,45,(11)(12)Fenton.2.4　FentonFenton,pH.62minpH.,FentonpH.Fenton,pH2.5～3.5;Fenton,pH2.8～3.0.Fenton,pH2.5,,3.5Fe3+,[13].Fenton,Fe3+pH,pH[14].[H2O2]0:5.0mmol/L;[Fe2+Fe3+]0:=0.5mmol/L;pH=7.4PBS;DMPO:150mmol/L6　pH·OHFig.6　EffectofpHon·OHformation7pH=3.0FentonFenton.H2O2,FentonFenton,,.Fenton,FentonFenton.[H2O2]0:5.0mmol/L;[Fe2+Fe3+]0=0.5mmol/L;pH:3.0;DMPO:150mmol/L;pH:7.4PBS7　·OHFig.7　Changeof·OHinFentonandFenton-likeprocess81min,H2O2Fe2+.,Fenton,Fe2+,308　　　　　　27Fe2+H2O2.Fe2+FentonH2O2Fenton.[H2O2]0=5.0mmol/L;Fenton:[Fe2+Fe3+]0=0.5mmol/L;pH=3.0;t=25℃8　FentonFentonFe2+H2O2Fig.8　ChangeofFe2+andH2O2inFertonandFerton-likeprocess[12,15],pHFentonFe3+,.,pHFentonFe3+Fenton.FentonFenton[2,3,16,17],:Fenton,Fe3+Fenton,Fe2+Fenton[17]..,FentonFenton,FentonFenton.FentonH2O2Fenton,.3　(1)ESR,DMPOFenton/Fenton:PBSpH7.4;DMPO150mmol/L.(2)2,H2O2Fe2+Fe3+.,Fenton,Fenton,.(3)FentonFenton,pH:2.5～3.52.8～3.0.(4)FentonFenton.:[1]BarbWG,BaxendaleJH,GergeP,etal.Reactionofferrousandferricionswithhydrogenperoxide.PartI—Theferrousionr