好氧条件下铬污染土壤中Cr(Ⅵ)的土著微生物还原

Trans.NonferrousMet.Soc.China29(2019)1304−1311Cr(VI)reductioninchromium-contaminatedsoilbyindigenousmicroorganismsunderaerobicconditionChang-qingSU1,Li-qingLI1,3,Zhi-huiYANG2,3,Li-yuanCHAI2,3,QiLIAO2,3,YanSHI2,3,Jia-weiLI21.SchoolofEnergyScienceandEngineering,CentralSouthUniversity,Changsha410083,China;2.SchoolofMetallurgyandEnvironment,CentralSouthUniversity,Changsha410083,China;3.ChineseNationalEngineeringResearchCenterforControlandTreatmentofHeavyMetalPollution,CentralSouthUniversity,Changsha410083,ChinaReceived17July2018;accepted14January2019Abstract:Bioremediationplaysanincreasinglyimportantroleintheremediationofchromium-contaminatedsoilbecauseitisanenvironmentallyfriendlytechnology.ToinvestigatetheCr(VI)reductionprocessbyindigenousmicroorganismsinsoil,abatchofincubationexperimentswerecarriedoutinabioreactorunderaerobicconditions.Theresultsshowedthatinthepresenceofindigenousmicroorganisms,theCr(VI)concentrationinthechromium-contaminatedsoildecreasedfrom1521.9to199.2mg/kgwithin66hwithculturemediumaddition,whileaslightdecreaseintheCr(VI)concentrationwasfoundinthesterilizedsoil,implyingthattheindigenousmicroorganismscontributedtotheCr(VI)reduction.Inthemicrobialremediationprocess,Cr(VI)microbialreductionoccurredafterthereductionof3NO,Mn4+andFe3+and,before24SOreduction.ThereductionprocessofCr(VI)canbedividedintotwophases,characterizedbytheexponentialequationmodelofmicrobialreductionandthelinearequationmodelofthecombinedeffectofthemajorions.ItcanbeconcludedthatindigenousCr(VI)-reducingbacteriahaveapotentialapplicationforin-situremediationofCr(VI)-contaminatedsoil.Keywords:Cr(VI)-contaminatedsoil;indigenousmicroorganisms;microremediation;kinetics1IntroductionChromiumanditscompoundsarewidelyusedinvariousindustriesandbecomepollutantsinsoil,industrialwastewaterandgroundwater[1].Bothvalencestates,trivalentandhexavalent,ofchromiumareubiquitousinnature.Trivalentchromium(Cr(III))haslowtoxicityandactivity.However,hexavalentchromium(Cr(VI))hashightoxicityandmobility,causing