零价铁电子传递对产甲烷和还原硫酸根影响

ZeroValentIronasanElectron-DonorforMethanogenesisandSulfateReductioninAnaerobicSludgeSrilakshmiKarri,ReyesSierra-Alvarez,JimA.FieldDepartmentofChemicalandEnvironmentalEngineering,UniversityofArizona,P.O.Box210011,Tucson,Arizona85721-0011;telephone520-626-5858;fax.520-621-6048;e-mail:jimfield@email.arizona.eduReceived15April2005;accepted16June2005Publishedonline31August2005inWileyInterScience(www.interscience.wiley.com).DOI:10.1002/bit.20623Abstract:Zerovalentiron(ZVI)isareactivemediacommonlyutilizedinpermeablereactivebarriers(PRBs).SulfatereducingbacteriaarebeingconsideredfortheimmobilizationofheavymetalsinPRBs.ThepurposeofthisstudywastoevaluatethepotentialofZVIasanelectrondonorforsulfatereductioninnaturalmixedanaerobiccultures.TheabilityofmethanogenstoutilizeZVIasanelectron-donorwasalsoexploredsincethesemicroorganismsoftencompetewithsulfatereducersforcommonsubstrates.FourgradesofZVIofdifferentparticlesizes(1.120,0.149,0.044,and0.010mmdiameter)werecomparedaselectrondonorinbatchbioassaysinoculatedwithanaerobicbioreactorsludge.Methano-genesiswasevaluatedinmineralmedialackingsulfate.Sulfatereductionwasevaluatedinmineralmediacon-tainingsulfateandthespecificmethanogenicinhibitor,2-bromoethanesulfonate.ZVIcontributedtosignificantincreasesinmethaneproductionandsulfatereduction-comparedtoendogenoussubstratecontrols.TheratesofmethaneformationorsulfatereductionwerepositivelycorrelatedwiththesurfaceareaofZVI.Thehighestratesof0.310mmolCH4formed/molFe0�dayand0.804mmolSO42�reduced/molFe0�daywereobtainedwiththefinestgradeofZVI(0.01mm).TheresultsdemonstratethatZVIisreadilyutilizedasaslow-releaseelectrondonorformethanogenesisandsulfatereductioninanaerobicsludge;andtherefore,hasapromisingpotentialinbioremediationapplications.�2005WileyPeriodicals,Inc.Keywords:anaerobic;metalliciron;Fe0;elementaliron;elementalmetal;bioremediation;permeablereactivebarriersINTRODUCTIONPermeablereactivebarriers(PRB)arearelativelysimpleremediationtechnologyinwhichazoneofsemipermeablereactivemediaisplacedi