NanotechnologyforEnvironmentalRemediation ModernInorganicChemistry SeriesEditor:JohnP.Fackler,Jr.,TexasA&MUniversity Currentvolumesinthisseries: ExtractionofMetalsfromSoilsandWaters D.M.Roundhill MetalDihydrogenandSigma-BondComplexes G.J.Kubas Carbon-FunctionalOrganosiliconCompounds EditedbyVaˇclavChvalovsky´andJonM.Bellama ComputationalMethodsfortheDeterminationofFormationConstants EditedbyD.J.Leggett CooperativePhenomenainJahn–TellerCrystals M.D.KaplanandB.G.Vekhter GasPhaseInorganicChemistry EditedbyD.H.Russell HomogeneousCatalysisWithMetalPhosphineComplexes EditedbyLouisH.Pignolet InorganometallicChemistry EditedbyT.P.Fehlner TheJahn-TellerEffectandVibronicInteractionsinModernChemistry I.B.Bersuker MetalComplexesinAqueousSolutions ArthurE.MartellandRobertD.Hancock Mo¨ssbauerSpectroscopyAppliedtoInorganicChemistry (cid:1) Volumes1and2 EditedbyGaryJ.Long (cid:1) Volume3 EditedbyGaryJ.LongandFernandeGrandjean Mo¨ssbauerSpectroscopyAppliedtoMagnetismandMaterialsScience (cid:1) Volumes1and2 EditedbyG.J.LongandF.Grandjean NanotechnologyforEnvironmentalRemediation SungHeeJooandI.FrancisCheng OptoelectronicPropertiesofInorganicCompounds EditedbyD.M.RoundhillandJohnP.Fackler,Jr. OrganometallicChemistryoftheTransitionElements F.P.Pruchnik TranslatedfromPolishbyStanA.Duraj PhotochemistryandPhotophysicsofMetalComplexes D.M.Roundhill Sung Hee Joo I. Francis Cheng Nanotechnology for Environmental Remediation With79Illustrations SungHeeJoo I.FrancisCheng EnvironmentalEngineeringProgram DepartmentofChemistry CivilEngineeringDepartment UniversityofIdaho AuburnUniversity Moscow,ID83844 Auburn,AL36849 USA USA [email protected] [email protected] LibraryofCongressControlNumber:2005932036 ISBN-10:0-387-28825-2 e-ISBN:0-387-28826-0 ISBN-13:978-0387-28825-3 Printedonacid-freepaper. (cid:1)C 2006SpringerScience+BusinessMedia,Inc. Allrightsreserved.Thisworkmaynotbetranslatedorcopiedinwholeorinpartwithoutthewritten permissionofthepublisher(SpringerScience+BusinessMedia,Inc.,233SpringStreet,NewYork, NY10013,USA),exceptforbriefexcerptsinconnectionwithreviewsorscholarlyanalysis.Use in connection with any form of information storage and retrieval, electronic adaptation, computer software,orbysimilarordissimilarmethodologynowknownorhereafterdevelopedisforbidden. 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(TB/MVY) 9 8 7 6 5 4 3 2 1 springer.com Preface Thebookcoverstherecentlydiscoveredoxidativeprocessdrivenbyzero-valent iron (ZVI) in the presence of oxygen and a further developed system which is namedZEA(Zero-valentiron,EDTA,Air).Futurepotentialapplicationsforenvi- ronmentalremediationusingthisprocessarealsodiscussed.Theoxidativeprocess wasdiscoveredduringthecourseofmolinate(athiocarbamateherbicide)degrada- tionexperiments.Bothferrousironandsuperoxide(or,atpH<4.8,hydroperoxy) radicalsappeartobegeneratedoncorrosionoftheZVIwithresultantproduction ofstronglyoxidizingentitiescapableofdegradingthetracecontaminant.Fenton oxidationandoxidativeby-productswereobservedduringnanosizedZVI(nZVI)- mediateddegradationofmolinateunderaerobicconditions.Toassessthepotential applicationofnZVIforoxidativetransformationoforganiccontaminants,thecon- version of benzoic acid (BA) to p-hydroxybenzoic acid (p-HBA) was used as a probereaction.WhennZVIwasaddedtoBA-containingwater,aninitialpulseof p-HBAwasdetectedduringthefirst30minutes,followedbytheslowgeneration ofadditionalp-HBAoverperiodsofatleast24hours.TheZEAsystemshowed thatchlorinatedphenols,organophosphorusandEDTAhavebeendegraded.The mechanism by which the ZEA reaction proceeds is hypothesized to be through reactiveoxygenintermediates.TheZVI-mediatedoxidationandZEAsystemmay beusefulforinsituapplicationsofnZVIparticlesandmayalsoprovideameans ofoxidizingorganiccontaminantsingranularZVI-containingpermeablereactive barriers. Thepurposeofthisbookistoprovideinformationontherecentlydiscovered chemicalprocess,whichcouldrevolutionizethetreatmentofpesticidesandcon- taminated water. It also aims to offer significant insights to the knowledge for potentialapplicationsofZVI-basedtechnology. Oxidative degradation of herbicides (e.g., molinate) with its pathway, mecha- nisticinterpretationofthedata,modelling/simulation,implicationforremediation applications,experimentalmethodologysuitableforpesticidesanalysis,andZEA (Zero-valent iron, EDTA, and Air) system with its degradation mechanism are included. v Acknowledgments WewouldliketodeeplyacknowledgeDr.ChristinaNoradounwhocontributedher expertiseinChapter5.Dr.Joowishestothankformermentors,ProfessorDavid WaiteandDr.AndrewFeitzfortheiradviceduringresearchonthistopic.Special thanksgotoDr.JosephPignatellowhoprovidedinsightfulcommentsinpreparing themanuscript. Finally we would like to appreciate reviewers’ comments, which improve the quality of this book and the senior editor, Kenneth Howell who supported us in thepreparationofthisbook. vii Contents Preface................................................................................... v Acknowledgments..................................................................... vii AbbreviationsandSymbols........................................................ xiii Chapter1. Introduction........................................................... 1 1.1. Objectives....................................................................... 2 1.2. Outlines......................................................................... 3 Chapter2. LiteratureReview.................................................... 5 2.1. Zero-ValentIron(ZVI)....................................................... 5 2.1.1. IronUseintheEnvironment....................................... 5 2.1.2. NanoparticulateBimetallicandIronTechnology.............. 7 2.1.3. PermeableReactiveBarrier(PRB)UsingGranularZVI..... 8 2.1.4. PRBandZVIColloids.............................................. 9 2.1.5. UseofZVI,H O ,andComplexants............................ 10 2 2 2.1.6. NanosizedZVI(nZVI).............................................. 11 2.2. PesticidesandContamination............................................... 12 2.2.1. Introduction........................................................... 12 2.2.2. CharacteristicsofPesticidesandTheir EnvironmentalEffects.............................................. 13 2.2.3. CommonlyUsedPesticides........................................ 16 2.2.4. PesticidesTreatmentandManagementPractices.............. 18 2.3. Summary........................................................................ 22 Chapter3. NanoscaleZVIParticlesManufacture andAnalyticalTechniques.......................................................... 25 3.1. SynthesisofNanoscaleZVIParticles..................................... 25 3.1.1. ZVIParticleCharacterization...................................... 26 3.2. AnalyticalTechniques........................................................ 28 3.2.1. Solid-PhaseMicroextractionGC/MSD.......................... 28 3.2.2. HPLCAnalysisofBenzoicAcidandp-HydroxybenzoicAcid 34 ix x Contents 3.2.3. MeasurementofFerrousIronConcentrations.................. 34 3.2.4. MeasurementofHydrogenPeroxide (H O )Concentrations.............................................. 34 2 2 3.3. ProceduresUsedinnZVI-MediatedDegradationStudies............. 35 3.3.1. MolinateDegradation............................................... 35 3.3.2. BenzoicAcidDegradation......................................... 36 3.4. ExperimentalSetupUsedinZEASystemStudies ..................... 37 3.5. DeterminationofZVISurfaceProductsbyXRD....................... 39 3.5.1. MeasurementsinthePresenceofMolinate..................... 40 3.5.2. MeasurementsintheAbsenceofMolinate..................... 40 Chapter4. OxidativeDegradationoftheThiocarbamate Herbicide,Molinate,UsingNanoscaleZVI..................................... 41 4.1. Introduction.................................................................... 41 4.2. Results........................................................................... 41 4.2.1. EffectofthePresenceofAir/Oxygen............................ 41 4.2.2. EffectofMolinateandZVIConcentration...................... 42 4.2.3. EffectofpH........................................................... 44 4.2.4. FerrousIronGeneration............................................ 45 4.2.5. EffectofDO.......................................................... 52 4.2.6. HydrogenPeroxideGeneration................................... 53 4.2.7. CatalaseandButanolCompetition................................ 55 4.2.8. DegradationBy-products .......................................... 56 4.3. MolinateDegradationbyCombinedZVIandH O .................... 58 2 2 4.3.1. EffectofZVIatFixedHydrogen PeroxideConcentration ............................................ 60 4.3.2. EffectofHydrogenPeroxideatConstantZVI................. 60 4.3.3. DegradationBy-productsbyCombinedZVIandH O ...... 61 2 2 4.3.4. Fe(II)GenerationfromCoupledZVI/H O inthe 2 2 PresenceofMolinate................................................ 64 4.4. MolinateDegradationUsingFenton’sReagent.......................... 64 4.4.1. DegradationBy-productsofMolinateUsing Fenton’sReagents................................................... 67 4.5. ComparisonofZVI,CoupledZVI/H O andFenton’s 2 2 ProcessatHighpH............................................................ 69 4.6. XRDandXPSAnalysis...................................................... 69 4.6.1. ResultsofXRDAnalysis........................................... 69 4.6.2. XPSResults........................................................... 73 4.7. Discussion...................................................................... 73 4.7.1. EvidenceofOxidationPathway................................... 73 4.7.2. ReactionMechanism................................................ 75 4.7.3. KineticsofFe(II)andH O Generation......................... 79 2 2 4.7.4. OverviewoftheZVI-MediatedOxidativeTechnology ...... 79 4.8. Conclusion...................................................................... 80 Contents xi Chapter5. MolecularOxygenActivationbyFeII/IIIEDTA asaFormofGreenOxidationChemistry∗..................................... 83 5.1. OxygenActivation............................................................ 83 5.2. XenobioticDegradationbyZEASystem................................. 85 5.3. MechanismofDegradation.................................................. 87 5.4. Rate-DeterminingStep....................................................... 88 5.5. IronChelationandChelateGeometryInfluenceReactivity........... 91 5.6. FormofReactiveOxygenIntermediateSpecies ........................ 94 5.7. Conclusion...................................................................... 95 Chapter6. QuantificationoftheOxidizingCapacityof NanoparticulateZero-ValentIronandAssessmentof PossibleEnvironmentalApplications............................................ 97 6.1. Introduction.................................................................... 97 6.2. Results........................................................................... 98 6.2.1. p-Hydroxybenzoicacid(p-HBA)Formation................... 98 6.2.2. CumulativeHydroxylRadicalFormationover LongTerm............................................................. 98 6.2.3. EffectofFe(II)asOxidantScavenger............................ 100 6.2.4. EffectofZVIConcentrationsonOxidantYield................ 101 6.2.5. EffectofpH........................................................... 103 6.2.6. SelectivityofOxidant............................................... 103 6.2.7. EffectofZVITypeonOxidantYields........................... 109 6.2.8. ComparisonStudyonStandardFentonOxidationof BenzoicAcid ......................................................... 109 6.2.9. EffectofPureO onOxidantYield.............................. 110 2 6.2.10.Discussion............................................................. 113 6.2.11.ConceptualKineticModeling..................................... 115 6.3. Conclusion...................................................................... 120 Chapter7. ConclusionsandFutureResearchNeeds...................... 123 7.1. ColumnStudies................................................................ 123 7.2. FurtherApplicationsoftheZVI-MediatedOxidativeProcess........ 124 7.3. SummaryofResults.......................................................... 125 7.4. OverviewofnZVIResearchandFurtherResearchNeeds............ 127 Chapter8. References............................................................. 129 AppendixA:XRDAnalysisofZVICollectedfrom FourDifferentSamples.............................................................. 147 AppendixB:XRDAnalysisofZVICollectedfrom FourDifferentSamples.............................................................. 149