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Membranefiltrationtechnologyisoftenemployedtoseparate,purifyandconcentratespecificcomponentsinorganicsolutionorgasflow,inviewofitscharacteristicsofhighefficiency,energysavingandenvironmentalprotectioncl-3].Inthelast3decades,organicmembraneswerewidelyusedinfiltrationandseparationdevices.However,theservicelifeoforganicmembraneswouldbesubstantiallyshortenedduetoeasilybeinghydrolyzedandcorrodedingeneralacidoralkalisolutions.Furthermore,theirmechanicalandthermalpropertiesarenotstableiftheworkingtemperatureisover1000C.Comparingtoorganicmembranes,ceramicmembraneshavemorestablechemical,mechanicalandthermalpropertiesrespondedtosurroundingenwronments[4-5].Ceramicmembranesaretherebymoreandmorepopularundersomeharshorhightemperaturecircumstances,andnowadays,arewidelyusedinchemicalindustry,petrochemicalindustry,metallurgicalindustry,foodindustry,etc.Mostimportantly,ceramicmembranescouldserveforalongertimeandbereusedformanytimeswhichleadstolessenwronmentalpollutions.However,ceramicmembranesalsohavetheirdrawbacks,suchascomplicatedmanufacturingprocessing,relativelylowseparationefficiencyandlimitedfunctionalapplicationsc6].Recently,anovelceramicmembranewithdesignedmicro-structureswassuccessfullypreparedinourlab.Theprocessingmethodisrelativelysimplecomparedwithtraditionalones.Firstly,aspecialelectrospinningequipmentwasemployedtofabricatenano-fiberswithwellalignedPolyvinylPyrrolidone(PVP)/HalloysiteNanotubes(HNTs)composites.Afterthealignednano-fibersweretailoredtodesiredmicro-structures,thecompositesheetwascalcinedinatubefurnaceat12000C一14000Cfor3hrswithaspecificheatingrate.Themicro-structuresofresultedceramicmembranewerecontrolledbyalteringtheparametersforfabricationofPVP/HNTscompositenano-fibersduringelectrospinningprocess.Experimentalresultsshowthattheporesizeoftheseceramicmembranescanbecontrolledfromabout200nmt04ym;andtheporositycanbecontrolledfrom35%t085%.Afterbeingimmersedindilutesulphuricacidfor7days,theweightlosswaslessthanl%.Thismembranewillbefurtherfunctionalizedbymountingselectedfunctionalorganicgroupsandpropercatalystsonitssurfacetoenhanceitsselectivefiltrationandseparationproperties.Forinstance,Palladium(Pd)modifiedceramicmembranecouldbeusedtoselectivelyseparatehydrogenandnitrogencr],andnano-silverdepositedonehasthefunctionofbactericidalcapabilityc8],etc.Inaword,thisnovelceramicmembraneafterfunctionalizationhasthegreatpotentialtobewidelyappliedinwater-treatmentequipments,airpurificationdevicesandeveninthefieldofrenaldialysis. |
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