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1、Articlepubs.acs.org/estElectrochemicalMineralizationofPerfluorocarboxylicAcids(PFCAs)byCe-DopedModifiedPorousNanocrystallinePbO2FilmElectrodeJunfengNiu,*HuiLin,JialeXu,HaoWu,andYangyangLiStateKeyLaboratoryofWaterEnvironmentSimulation,SchoolofEnvironment,BeijingNormalUniversity,Beijin
2、g100875,P.R.China*SSupportingInformationABSTRACT:TheCe-dopedmodifiedporousnanocrystallinePbO2filmelectrodepreparedbyelectrodepositiontechnologywasusedforelectrochemicalmineralizationofenvironmentallypersistentperfluorinatedcarboxylicacids(PFCAs)(∼C4−C8),i.e.,perfluorobutanoicacid(PFBA)
3、,perfluopentanoicacid(PFPeA),perfluorohexanoicacid(PFHxA),perfluoheptanoicacid(PFHpA),andperfluorooctanoicacid(PFOA)inaqueoussolution(100mLof100mgL−1).ThedegradationofPFCAsfollowspseudo-first-orderkinetics,andthevaluesoftherelativerateconstant(k)dependuponchainlengthk(4.1×10−2min−1;corr
4、espondingPFHpAhalf-life16.8min)≈1.1kPFOA≈2.5kPFHxA≈6.9kPFPeA≈9.7kPFBA.Thecarbonmineralizationindices[i.e.,1−(TOCinsolution/TOCinPFCA,degraded)]were0.49,0.70,0.84,0.91,and0.95forPFBA,PFPeA,PFHxA,PFHpA,andPFOA,respectively,after90minelectrolysis.Themajormineralizationproduct,F−,aswel
5、laslowamountofintermediatePFCAswithshortenedchainlengthsweredetectedinaqueoussolution.Byobservingtheintermediatesandtrackingtheconcentrationchange,apossiblepathwayofelectrochemicalmineralizationisproposedasfollows:Kolbedecarboxylationreactionoccursfirstattheanodetoformtheperfluoroalk
6、ylradical,followedbyreactionwithhydroxylradicalstoformtheperfluoroalkylalcoholwhichthenundergoesintramolecularrearrangementtoformtheperfluoroalkylfluoride.Afterthis,theperfluoroalkylfluoridereformsperfluorinatedcarboxylicwithshorterchainlengththanitsoriginbyhydrolysis.Thiselectrochemical
7、techniquecouldbeemployedtotreatPFCAs(∼C4−C8)incontaminatedwastewater.1516,1712,18■INTRODUCTIONexchange,membraneseparation,photolyticmethods,1920photoelectrocatalysis,plasmaoxidation,ultrasonicirradi-Perfluorocarboxylicacids(PFCAs)suchasperfluorobutanoic21−232425ation,zerovalentironre
8、duction,thermolysis,andaci