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ElectrocoagulationfortheeffectiveremovalofpollutantsAdelaideDuraandCarmelB.BreslinDepartmentofChemistry,NationalUniversityofIrelandMaynooth,Maynooth,Co.Kildare,Ireland.Theexistingwastewatertreatmentsinvolvebiologicalandchemicalapproaches.Thebiologicaltreatmentsareeffective,butrequirelongtimes,largetreatmentfacilitiesandareexpensive.Thechemicalapproaches,whichinvolveaddingchemicalstoextractorprecipitatethepollutant,areveryeffectiveinremovingthetargetpollutant,buttheanionofthesaltaddedcancausesecondarypollutionandlargeamountsofsludge(1).Electrochemicaltechniquesare,inthiscase,promisingbecauseoftheirversatility,safety,selectivity,amenabilitytoautomationandenvironmentalcompatibility(2).Electrocoagulationappearstobeoneofthemosteffectiveapproachesandhasbeenproventoremoveawiderangeofpollutants,suchasdyes,heavymetals,COD,etc.,(1).Theprincipleisbasedontheelectrochemicaloxidationofametaltogenerateacontrolledamountofmetalcations;thesecationscanthenformacoagulantwiththepollutant,whichinturncanberemoved(Figure1).Thishastheaddedadvantagethatthemetalcationsareintroducedin-situratherthanbyexternaldosing.Moreover,electrocoagulationischaracterizedbysimpleandeasytooperateequipment,shortoperationtime,noneornegligibleamountsofchemicals,andlowsludgeproduction.Figure1–Principleofelectrocoagulation(RE=referenceelectrode,WE=workingelectrode,CE=counterelectrode).Inthisstudytheremovalofturbidity,phosphatesandadyewasinvestigatedusingdifferentelectrodematerials,mainlyironandaluminiumalloys.Thebestperformingmaterialswerealuminium/magnesiumalloyandstainlesssteel420aspassivationonlyslightlyoccurredorcouldbereducedinlowsaltcontentsolutions.1.M.Y.A.Mollah,P.Morkovsky,J.A.Gomes,eta.,.J.Hazard.Mater.,84(2001).2.K.Rajeshwar,J.G.IbanezandG.M.Swain,J.Appl.Electrochem.,24(1994).REPollutantsM(OH)nMMn+CoagulationandflocculationCEWEAbstract#1417,221stECSMeeting,©2012TheElectrochemicalSociety