多孔莫来石陶瓷英文文献

JournalofHazardousMaterials273(2014)136–145ContentslistsavailableatScienceDirectJournalofHazardousMaterialsjournalhomepage:üa,b,c,XinfaDongc,ZhiwenZhua,b,YingchaoDonga,b,∗aInstituteofUrbanEnvironment,ChineseAcademyofSciences,Xiamen,PRChinabNingboUrbanEnvironmentObservationandResearchStation-NUEORS,ChineseAcademyofSciences,Ningbo,PRChinacSchoolofChemistryandChemicalEngineering,SouthChinaUniversityofTechnology,Guangzhou,PRChinahighlights•Coalganguewasrecycledtofabricatelow-costporousmullitemembranesupports.•Auniquevolume-expansionoccurredduetoamullitization-crystal-growthprocess.•Aporousstructureconsistsofglassyparticlesandembeddedmullitecrystals.articleinfoArticlehistory:Received23December2013Receivedinrevisedform20February2014Accepted19March2014Availableonline27March2014Keywords:CoalgangueWasterecyclingCeramicmembranePorousmulliteMechanicalstrengthabstractPorousmulliteceramicsupportsforfiltrationmembraneweresuccessfullyfabricatedviarecyclingofcoalgangueandbauxiteatsinteringtemperaturesfrom1100to1500◦Cwithcornstarchaspore-formingagent.Thedynamicsinteringbehaviors,phaseevolution,shrinkage,porosityandporesize,gaspermeationflux,microstructureandmechanicalpropertyweresystematicallystudied.Auniquevolume-expansionstagewasobservedatincreasedtemperaturesfrom1276to1481◦Ccausedbyamullitization-crystal-growthprocess.Duringthisstage,openporosityincreasesandporesizedistribu-tionsbroaden,whichresultinamaximumofnitrogengasfluxat1400◦C.TheX-raydiffractionresultsrevealthatsecondarymullitizationtookplacefrom1100◦Candthemajorphaseismullitewithacon-tentof∼84.7wt.%at1400◦C.SEMimagesshowthattheas-fabricatedmullitesupportshaveaporousmicrostructurecomposedofsinteredglassyparticlesembeddedwithinter-lockedmullitecrystals,whichgrewgraduallywithincreasingtemperaturefromrod-likeintoblocky-likemorphologies.Toobtainmul-litemembranesupportswithsufficientporosityandacceptablemechanicalstrength,therelationshipbetweenporosityandmechanicalstrengthwasinvestigated,whichwasfittedusingaparabolicequation.©2014ElsevierB.V.Allrightsreserved.1.IntroductionCoalgangue,anindustrialsolidwaste,isoneoftheby-productsduringcoalmining.Theproductionratioofcoalganguevariesfrom∼10%to15%ofrawcoal,whichmainlydependsonminingandgeo-logicalconditions[1,2].Currentlymostofwastecoalgangueispiledonland,whichcancauseseriousenvironmentalimpacts,especiallytheatmosphericpollutioncausedfromspontaneouscombustionandwaterpollutionfromleachingandreleaseofheavymetalions∗Correspondingauthorat:InstituteofUrbanEnvironment(IUE)ChineseAcademyofSciences(CAS),InorganicMembrane&EnvironmentalMaterials,1799,JimeiRoad,Xiamen,FujianProvince361021,PRChina.Tel.:[phone];fax:[phone].E-mailaddress:[e-mail](Y.Dong).[3–5].Therefore,thecomprehensiveutilizationofcoalgangueisquitenecessary.Manyapproachesonreusingofcoalganguehavebeenreportedsofar.Mostofcoalgangueafterprocessingisusedfortraditionalconstructionmaterials,suchascement[6]andbrick[7].Thecoalganguewithhighcontentofcarbonismixedwithothertypesofcoalformine-mouthpowergeneration,whichhasindi-cateditstechno-economicfeasibilityofmine-mouthpowerplants[8].Ingeneral,themajormineralogicalphasecompositionofcoalgangueisquartzandfeldspar[9,10],withmainchemicalcompo-sitionofSiO2,Al2O3,Fe2O3andsomeotherminoroxidesuchasK2OandTiO2.Comparedwithotherindustrialwastesandmineralssuchascoalflyash,kaolin,andalusiteandsillimanite,particularly,thecontentofSiO2incoalgangueisgenerallyashighas∼70%,soitcanbeconsideredasapotentiallow-costsiliconsourceinindustry.Therearesomestudiesonthefabricationofglassesandceramicsbyreusingofcoalgangue.Yangetal.preparedaCaO–Al2O3–SiO2©2014ElsevierB.V.Allrightsreserved.Q.Lüetal./JournalofHazardousMaterials273(2014)136–145137glassceramicfromcoalgangue[11],and-SiC/Al2O3ceramicshavebeenfabricatedfromkaolinitegangueandanthracitebyHanetal.[12].Porousceramicseparationmembraneshavebeenwidelystudiedforenergyandenvironmentalapplicationsduetoitsuniqueadvantagesespeciallysuchashighthermal,chemicalandmechanicalstability,environmentfriendlinessandlowenergy-consumption[13].However,becauseporousceramicseparationmembranesrequireamuchhighercostthanpolymericcounter-parts,theirapplicationshavebeenlimitedinsometraditionalindustrysuchasfood,beverageandpharmaceutical.Also,limitedtypesofmembranematerials(suchasAl2O3,ZrO2,TiO2andtheircompositeoxides)hindertheirfurtherapplications[14–16].Withincreasedneedsofsomeenvironmentalseparationapplicationssuchasstrongacidic/alkalinemediaseparation,massivewasteliq-uidpre-treatmentandlow-costcatalysis-separationsupports,itisofgreatimportancetodeveloplow-costfabricationandapplicationtechniquesforceramicmembranes.Amongceramicmembranematerials,porousmullite(from3Al2O3·2SiO2to2Al2O3·SiO2)hasbeenattractingmoreandmoreattentionsasmembranesupportsbecauseofitsuniqueadvan-tagessuchasgoodchemicaldurability,lowthermalexpansioncoefficient