Mechanisms of heavy-metal removal by activated sludge .pdf

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1、Chemosphere75(2009)1028–1034ContentslistsavailableatScienceDirectChemospherejournalhomepage:www.elsevier.com/locate/chemosphereMechanismsofheavy-metalremovalbyactivatedsludgeF.Pagnanelli*,S.Mainelli,L.Bornoroni,D.Dionisi,L.ToroDepartmentofChemistry,SapienzaUniversityofRome,P.leA.Moro

2、5,00185Rome,ItalyarticleinfoabstractArticlehistory:ThispaperinvestigatesthechemicalmechanismsoperatingincadmiumandleadremovalbyactivatedReceived10November2008sludgeinsequencingbatchreactors.SelectiveextractionandaciddigestionofsludgesamplesdenotedReceivedinrevisedform11January2009tha

3、tbothCdandPbaremainlypresentassurface-boundmetals.CharacterisationofsludgesamplesAccepted13January2009bypotentiometrictitrationsandIRspectrasuggestedthatcarboxylicandaminogroupsarethemainAvailableonline10February2009activesitesresponsibleforthebindingpropertiesofthebiomass.Simulation

4、ofmetalspeciationimple-mentedwithcomplexationconstantsdeterminedinbiosorptiontests,showedthatcadmiumpredomi-Keywords:natesasbiosorbedspecies,whileleadwasmainlyremovedbyprecipitation.BiosorptionÓ2009ElsevierLtd.Allrightsreserved.HeavymetalsActivatedsludgePotentiometrictitrationMetalsp

5、eciation1.Introductionisthenprimarilyaphysico-chemicalratherthanabiologicalpro-cessbasedonionexchange,complexationandsurfacemicropre-Since1970sheavymetalshavebeencausingagrowingconcerncipitationreactionsinvolvingalargevarietyofbindingsitesofovertheirtoxiceffectsonhumansandaquaticecos

6、ystems.Asig-extracellularpolymericsubstances(EPS)andbacterialcellsurfacesnificantpartofanthropogenicemissionscontainingheavymetals(Pletteetal.,1995;VegliòandBeolchini,1997;Coxetal.,1999;endsupinwastewaterstreatedbyactivatedsludgeprocesses,Guibaudetal.,2005).affectingmicrobialbiomassgr

7、owthandthusthedepurativeeffi-Intheliteraturethebiosorbingpropertiesofactivatedsludgeciencyofthetreatment.Infactbiologicalwastewatersystemswerewidelyinvestigatedshowinghowthesewastescanbeusedaremainlydesignedfororganicmatterremovalandonlyside-ben-toremoveheavymetalsbyaqueoussolutions(G

8、ulnazetal.,e