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1、毕业设计（论文）外文文献翻译院系：厦门理工学院环境工程年级专业：姓名：学号：附件：BacterialSorptionofHeavyMetals指导老师评语：指导教师签名：年月日22BacterialSorptionofHeavyMetalsFourbacteria,Bacilluscereus,B.subtilis,Escherichiacoli,andPseudomonasaeruginosa,wereexaminedfortheabilitytoremoveAg+,Cd2+,Cu2+,andLa3+fromsolutionbybatchequilibrationmethods
2、.CdandCusorptionovertheconcentrationrange0.001to1mMwasdescribedbyFreundlichisotherms.At1mMconcentrationsofbothCd2+andCu2+,P.aeruginosaandB.cereuswerethemostandleastefficientatmetalremoval,respectively.FreundlichKconstantsindicatedthatE.coliwasmostefficientatCd2+removalandB.subtilisremovedthem
3、ostCu2+.RemovalofAg+fromsolutionbybacteriawasveryefficient;anaverageof89%ofthetotalAg+wasremovedfromthe1mMsolution,whileonly12,29,and27%ofthetotalCd2+,Cu2+,andLa3+,respectively,weresorbedfrom1mMsolutions.ElectronmicroscopyindicatedthatLa3+accumulatedatthecellsurfaceasneedlelike,crystallinepre
4、cipitates.Silverprecipitatedasdiscretecolloidalaggregatesatthecellsurfaceandoccasionallyinthecytoplasm.NeitherCd2+norCu2+providedenoughelectronscatteringtoidentifythelocationofsorption.TheaffinityseriesforbacterialremovalofthesemetalsdecreasedintheorderAg>La>Cu>Cd.Theresultsindicatethatbacter
5、ialcellsarecapableofbindinglargequantitiesofdifferentmetals.Adsorptionequationsmaybeusefulfordescribingbacterium-metalinteractionswithmetalssuchasCdandCu;however,thisapproachmaynotbeadequatewhenprecipitationofmetalsoccurs.Thefateoftoxicmetalliccationsinthesoilenvironmentdependslargelyontheint
6、eractionsofthesemetalswithinorganicandorganicsurfaces.Theextenttowhichametalliccationinteractswiththesesurfacesdeterminestheconcentrationofmetalinsolutionand,consequently,thepotentialformovementintogroundwateroruptakebyplants.Aconsiderableamountofworkhasbeendonetoevaluatetheadsorptionorcomple
7、xationofvariousheavymetalsbysoils(11)andsoilconstituents,suchasclays(22)andorganicmatterfractions(28).Onepotentiallyimportantorganicsurfacewhichhasreceivedlittleattentionisthatofthesoilmicrobialpopulation.Soilmicroorganismsaretypicallyassocia
