简介：Inthisstudy,titaniumdioxidesupportedbymulti-walledcarbonnanotubes(MWCNTs/TiO2)andCr-dopedTiO2supportedbyMWCNTs(MWNTs/Cr-TiO2)weresynthesizedbythesol-gelmethod.Thepreparedsampleswerecharacterizedbytransmissionelectronmicroscopy,X-rayphotoelectronspectroscopy,X-raydiffraction,theBrunauerEmmett-Telleranalysis,andtheRamanspectroscopy.TheoxidationandefficiencyforremovalofSO2inasimulatedfluegaswereinvestigatedexperimentallyinafixed-bedreactor.The15%MWCNTs/Cr-Ti02sampledisplayedexcellentadsorptionproperties,andaSO2removalrateequatingto30.4151mg/gfromthesimulatedfluegascontaining2300μg/gofSO2,8%of02,and5%ofH20wasachievedunderoptimalconditionscoveringatemperatureof333.15K,andaspacevelocityof1275h^-1.TheadsorptionprocesswasenhancedbecauseCrdopingmodifiedtheporestructureandinhibitedthegraingrowthofTiO2.Inaddition,theFreundlichandLangmuirmodelsrevealedthatSO2wasmainlyadsorbedthroughchemicaladsorptiononthesamplesurfaces,andthethermodynamicmodelanalysisindicatedthattheadsorptionwasaspontaneous,exothermic,andentropy-reducingprocess.TheadsorptionkineticsofSO2canbedescribedbythepseudosecond-orderkineticandtheBanghamdynamicsmodels.Thepossiblereactionmechanisminvolvedindesulfurizationprocesswasalsoproposed.

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简介：Chromiumacetylacetonateandbis(diphenylphosphino)isopropylaminewerecoordinatedinsituandsupportedonmethylaluminoxane-modifiedsilica.Thecatalyststructureandeffectsofreactiontemperature,reactionpressureandAl/Crmolarratioonethylenetetramerizationwereinvestigatedindetail.Chromiumwasuniformlyandfirmlyimmobilizedonthesupportandcouldnotbeleachedoffbymethylaluminoxane.Thesupportedcatalyst,uponbeingactivatedwithmethylaluminoxane,exhibitedcatalyticactivityof1.70×107g/(molCr·h)forethylenetetramerizationtoform1-octeneatareactiontemperaturesof80℃,apressureof2.0MPaandanAl/Crmolarratioof300.Thesupportedcatalystpresentedagoodtolerancetohightemperature.

简介：SixNi-MocatalystswithdifferentmetalcontentswerepreparedandcharacterizedbyN2adsorptionandX-raydiffractometry.TheactivephasemicrostructureofthesecatalystswasexaminedbytheRamanspectroscopy,temperatureprogrammedreduction(TPR),X-rayphotoelectronspectroscopy,andhigh-resolutiontransmissionelectronmicroscopy.Hydrodesulfurization(HDS)activityofcatalystsampleswereanalyzedinaflowfixed-bedmicroreactor.ThesulfidationdegreeofMoandthelengthoftheMoS2slabslightlyincreasedwiththeamountofmetalloadedfollowingsulfidation.Thissmallchangeisattributedtopolymolybdatespeciesobservedinalltheoxidizedcatalysts.Weakmetal-supportinteractions,asdeterminedbytheTPRtechnique,increasedtheNiSxsulfidationphaseandMoS2slabstacking.TheHDSactivityofthecatalystsamplesincreasedwiththenumberofactivesites.Forhighmetalloadingcatalysts,theirHDSactivitywasnearlyidenticalbecausethesulfuratomscannoteasilyapproachactivesites.ThischangeiscausedbythelargenumberofstackedlayersintheMoS2slabsaswellasthedecreaseinthespecificsurfaceareaandporevolumeofthecatalystsampleswithanincreasingmetalloading.

简介：二季度,合成橡胶供需继续增长,但供应增速远高于需求增长,净进口量继续大幅减少。预计三季度丁二烯橡胶及丁苯橡胶平均价格与二季度基本持平或略高。

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