A-comparative-study-of-two-methods-for-the-synthesis-of-fly-ash-based-sodium

Acomparativestudyoftwomethodsforthesynthesisofflyash-basedsodiumandpotassiumtypezeolitesCarlosA.RíosR.a,b,*,CraigD.Williamsb,CliveL.RobertsbaEscueladeGeología,UniversidadIndustrialdeSantander,A.A678,Bucaramanga,ColombiabSchoolofAppliedSciences,TheUniversityofWolverhampton,WulfrunaStreet,CityCampus–South,WolverhamptonWV11LY,UKarticleinfoArticlehistory:Received17April2008Receivedinrevisedform4November2008Accepted10February2009Availableonline4March2009Keywords:FlyashSynthesisZeoliticmaterialsHydrothermalFusionabstractFlyash(FA)fromtheRugeleyPowerStation,WestMidlands(England)wasusedinastudyonsynthesisatlaboratoryscaleofzeoliticmaterialsundervariousconditionsbytwodifferentroutes.ZeoliticmaterialsweresynthesizedfromFAbyhydrothermaltreatmentinNaOH(Na-phillipsite,hydroxysodalite,hydroxycancrinite,tobermorite,analcimeandherschelite)andKOH(hydroxysodalite,zeoliteBarrer-KF,K-chabaziteandzeoliteLindeTypeF)solutions.ByfusionwithNaOHfollowedbyhydrothermalreac-tion,FAwasconvertedintofaujasiteandhydroxysodalite.NozeoliticmaterialswereobtainedbythismethodusingKOHasalkaliactivator.Theprocessofsynthesiswasoptimisedbyapplyingawiderangeofexperimentalconditionswithawiderangeofreactiontemperature,time,alkalihydroxideconcentra-tionandsolid/solutionratio.TheefficiencyFA-basedzeolites(FAZs)forheavymetalandammoniumuptakefromsyntheticsolutionsatlaboratoryscalehavebeeninvestigatedbytheauthors,revealingthattheseFAZsmayreachappropriatecationexchangecapacitiesfortheirapplicationinindustrialwastewa-tertreatment.�2009ElsevierLtd.Allrightsreserved.1.IntroductionGlobally,over500milliontonnesofFAaregeneratedeveryyearfromcoalcombustionbythermalpower-plantsanditsdisposalaslandfillposesmajorchallengesandseriouseconomicandenviron-mentalproblems.Theburningofcoalfortheproductionofelec-tricitysuppliesaround40%oftheUKelectricity,andthereforeFAisanabundantmaterial.Furthermore,theamountofdischargedmaterialisexpectedtoincreasedramaticallyinthefuture.Duetoincreasinglandfillcosts,stricterenvironmentalregulationandc