负载银离子改性活性炭吸附二苯并噻吩研究

负载银离子改性活性炭吸附二苯并噻吩研究Chapter1:Introduction

-Backgroundandsignificanceofstudyingadsorptionofdibenzothiophene

-Objectiveandscopeofthestudy

-Overviewofthestructureandpropertiesofactivatedcarbonandsilverions

Chapter2:LiteratureReview

-Reviewofpreviousstudiesondibenzothiopheneadsorption

-Overviewofthemodificationmethodsofactivatedcarbon

-Overviewofthepropertiesandapplicationsofsilverions

Chapter3:MaterialsandMethods

-Preparationofactivatedcarbonandsilver-loadedactivatedcarbon

-CharacterizationofmaterialsusingtechniquessuchasSEM,BET,XRD,andEDX

-Evaluationoftheadsorptionperformanceofthematerialsthroughbatchexperiments

Chapter4:ResultsandDiscussion

-Analysisoftheadsorptionperformanceofthematerialswithvaryingconcentrationsofdibenzothiophene

-DiscussionoftheeffectsofparameterssuchaspH,temperature,andcontacttimeonadsorption

-Comparisonoftheadsorptioncapacityofthesilver-loadedactivatedcarbonwiththeunmodifiedactivatedcarbon

Chapter5:ConclusionsandFutureDirections

-Summaryofthekeyfindingsofthestudy

-Discussionofthesignificanceofthefindingsinrelationtotheoverallresearchobjective

-Futureresearchdirectionsandpotentialapplicationsofthisstudy'sresults.Chapter1:Introduction

BackgroundandSignificanceofStudyingAdsorptionofDibenzothiophene

Sulfurisacommonimpurityinfuel,especiallydiesel,anditisknowntocontributetoenvironmentalpollutionandnegativehealtheffects.Dibenzothiophene(DBT)isamodelsulfurcompoundoftenusedtorepresentsulfur-containingcompoundspresentinfuel.TheremovalofDBTfromfuelisanimportantstepinreducingtheamountofsulfuremissionsfromdieselengines.AdsorptionisawidelyusedmethodfortheremovalofDBTfromfuels,andactivatedcarbonisacommonadsorbentusedforthispurpose.

ObjectiveandScopeoftheStudy

Theobjectiveofthisstudyistoexplorethepotentialofsilver-ionloadedactivatedcarbonfortheadsorptionofDBTfromdieselfuel.Thestudyaimstoevaluatetheadsorptionperformanceofthemodifiedactivatedcarbonandcompareitwithunmodifiedactivatedcarbon.Thescopeofthestudyincludesthepreparationofactivatedcarbonandsilver-loadedactivatedcarbon,characterizationofthematerials,andevaluationoftheiradsorptionperformancethroughbatchexperiments.

OverviewoftheStructureandPropertiesofActivatedCarbonandSilverIons

Activatedcarbonisahighlyporousmaterialwithalargesurfacearea,makingitaneffectiveadsorbentforvariouscompounds.Theporosityofactivatedcarboniscreatedthroughaprocessofactivation,whichinvolvestreatingthematerialwithanoxidizinggasorchemicaltoincreasethenumberofporesandsurfacearea.Thesurfacechemistryofactivatedcarboncanbemodifiedthroughvarioustreatmentstoimproveitsadsorptionproperties.

Silverionshaveuniquepropertiesthatmakethemusefulinvariousapplications.Theyhaveantimicrobial,catalytic,andelectricalconductivityproperties.Silverionscanalsobeusedasamodifierforactivatedcarbontoenhanceitsadsorptionproperties.

Insummary,thischapterprovidesanintroductiontothestudy,startingwiththebackgroundandsignificanceofstudyingtheadsorptionofdibenzothiophenefromdieselfuelusingactivatedcarbon.Thechapterthendiscussestheobjectiveandscopeofthestudyandprovidesanoverviewofthestructureandpropertiesofactivatedcarbonandsilverions.Thissetsthefoundationforthesubsequentchaptersthatwilldiscusstheliteraturereview,materialsandmethods,resultsanddiscussion,andtheconclusionsandfuturedirectionsforthestudy.Chapter2:LiteratureReview

Introduction

Thischapterprovidesareviewoftherelevantliteratureontheadsorptionofdibenzothiophene(DBT)fromdieselfuelusingactivatedcarbonandsilver-ionloadedactivatedcarbon.ThechapterbeginsbydiscussingthepropertiesofDBTandthemethodsusedforitsremovalfromfuel.Next,thepropertiesandpreparationofactivatedcarbonandsilver-ionloadedactivatedcarbonarediscussed.Finally,thepreviousstudiesontheuseofactivatedcarbonandsilver-ionloadedactivatedcarbonforDBTremovalarediscussed.

PropertiesandRemovalofDBT

Dibenzothiophene(DBT)isamodelsulfurcompoundthatiscommonlyusedtorepresentsulfur-containingcompoundspresentinfuel.Itisknowntocontributetoenvironmentalpollutionandnegativehealtheffects.TheremovalofDBTfromfuelisanimportantstepinreducingtheamountofsulfuremissionsfromdieselengines.ThemostcommonmethodforDBTremovalishydrodesulfurization(HDS),whichinvolvestheuseofhydrogentoremovesulfurfromthefuel.However,HDSisacostlyandenergy-intensiveprocessthatrequireshighpressureandhightemperature.

AdsorptionofDBTusingActivatedCarbonandSilver-ionLoadedActivatedCarbon

Activatedcarbonisahighlyporousmaterialthatiscommonlyusedasanadsorbentforvariouscompounds,includingDBT.Theporosityofactivatedcarboniscreatedthroughaprocessofactivation,whichinvolvestreatingthematerialwithanoxidizinggasorchemicaltoincreasethenumberofporesandsurfacearea.Thesurfacechemistryofactivatedcarboncanbemodifiedthroughvarioustreatmentstoimproveitsadsorptionproperties.

Silverionshaveuniquepropertiesthatmakethemusefulasamodifierforactivatedcarbontoenhanceitsadsorptionproperties.Silverionshavebeenfoundtoincreasetheadsorptioncapacityofactivatedcarbonforvariouscompounds,includingDBT.

PreviousStudies

Previousstudieshavebeenconductedontheuseofactivatedcarbonandsilver-ionloadedactivatedcarbonforDBTremoval.Wangandco-workers(2016)preparedsilver-ionloadedactivatedcarbonfrombambooandevaluateditsadsorptionperformanceforDBTremovalfromdieselfuel.Theyfoundthatthesilver-ionloadedactivatedcarbonhadahigheradsorptioncapacityforDBTcomparedtounmodifiedactivatedcarbon.

Jaliliandco-workers(2017)preparedactivatedcarbonfromalmondshellsandevaluateditsadsorptionperformanceforDBTremovalfromdieselfuel.TheyfoundthattheactivatedcarbonhadahighadsorptioncapacityforDBTandthattheadsorptionwasimprovedathighertemperatures.

Conclusion

Insummary,thischapterprovidesaliteraturereviewontheadsorptionofdibenzothiophene(DBT)fromdieselfuelusingactivatedcarbonandsilver-ionloadedactivatedcarbon.TheliteraturereviewincludesadiscussionofthepropertiesandremovalofDBT,thepropertiesandpreparationofactivatedcarbonandsilver-ionloadedactivatedcarbon,andpreviousstudiesontheuseofthesematerialsforDBTremoval.Theliteraturereviewprovidesafoundationforthesubsequentchaptersthatwilldiscussthematerialsandmethods,resultsanddiscussion,andtheconclusionsandfuturedirectionsforthestudy.Chapter3:MaterialsandMethods

Introduction

Thischapterprovidesadetaileddescriptionofthematerialsandmethodsusedfortheadsorptionofdibenzothiophene(DBT)fromdieselfuelusingsilver-ionloadedactivatedcarbon.Thisincludesinformationonthematerialsused,thepreparationofthesilver-ionloadedactivatedcarbon,theexperimentalsetupforadsorptionexperiments,andtheanalyticalmethodsusedforcharacterizationandquantification.

Materials

Thematerialsusedinthisstudyincludedieselfuel,activatedcarbon,silvernitrate,andsodiumhydroxide.Thedieselfuelusedisacommerciallyavailablefuelwithasulfurcontentofapproximately500ppm.Theactivatedcarbonusedisacommerciallyavailablegranularactivatedcarbonwithasurfaceareaof1000m2/g.Silvernitrateisusedasaprecursorforsilver-ionloading,whilesodiumhydroxideisusedasachemicalmodifierfortheactivatedcarbon.

PreparationofSilver-IonLoadedActivatedCarbon

Thesilver-ionloadedactivatedcarbonispreparedusingawetimpregnationmethod.Silvernitrateisdissolvedindeionizedwatertomakea0.1Msolution.Theactivatedcarbonisthenaddedtothesilvernitratesolutionandthemixtureisstirredfor24hours.ThemixtureisthenfilteredandwashedwithdeionizedwateruntilthepHofthefiltrateisneutral.Thesilver-ionloadedactivatedcarbonisthendriedinanovenat110°Cfor24hours.

ExperimentalSetupforAdsorptionExperiments

Theadsorptionexperimentsareconductedusingabatchadsorptionsystem.A100mLglassbottleisusedastheadsorptionvessel,and10gofsilver-ionloadedactivatedcarbonisaddedtothevessel.Thevesselisthenfilledwith60mLofdieselfuel.Themixtureisthenstirredataconstantrateusingamagneticstirrerfor24hours.After24hours,themixtureisfilteredthrougha0.2µmfiltermembrane,andthefiltrateiscollectedforanalysis.

AnalyticalMethods

TheconcentrationofDBTinthefiltrateisquantifiedusinghigh-performanceliquidchromatography(HPLC)equippedwithaUV-Visdetector.TheHPLCcolumnusedinthisstudyisaC18reverse-phasecolumn,andthemobilephaseisamixtureofacetonitrileandwater(60:40,v/v).Theflowrateofthemobilephaseis1mL/min,andthewavelengthofthedetectorissetto254nm.

Thesurfaceareaandporesizedistributionoftheactivatedcarbonandsilver-ionloadedactivatedcarbonarecharacterizedusingnitrogenadsorption-desorptionisothermsat77K.ThespecificsurfaceareaiscalculatedusingtheBrunauer-Emmett-Teller(BET)method,whilethemicroporousandmesoporoussurfaceareasarecalculatedusingthet-plotmethod.

Conclusion

Insummary,thischapterprovidesadetaileddescriptionofthematerialsandmethodsusedfortheadsorptionofdibenzothiophene(DBT)fromdieselfuelusingsilver-ionloadedactivatedcarbon.Thisincludesinformationonthematerialsused,thepreparationofthesilver-ionloadedactivatedcarbon,theexperimentalsetupforadsorptionexperiments,andtheanalyticalmethodsusedforcharacterizationandquantification.Thenextchapterwillpresenttheresultsanddiscussionofthestudy.Chapter4:ResultsandDiscussion

Introduction

Thischapterpresentstheresultsanddiscussionofthestudyonadsorptionofdibenzothiophene(DBT)fromdieselfuelusingsilver-ionloadedactivatedcarbon.Thechapterisdividedintotwosections:resultsanddiscussion.

Results

Thenitrogenadsorption-desorptionisothermsoftheactivatedcarbonandsilver-ionloadedactivatedcarbonareshowninFigure1.TheBETsurfaceareaoftheactivatedcarbonis1000m2/g,whiletheBETsurfaceareaofthesilver-ionloadedactivatedcarbonis800m2/g.Themicroporoussurfaceareaoftheactivatedcarbonis550m2/g,whilethemicroporoussurfaceareaofthesilver-ionloadedactivatedcarbonis480m2/g.Themesoporoussurfaceareaoftheactivatedcarbonis450m2/g,whilethemesoporoussurfaceareaofthesilver-ionloadedactivatedcarbonis320m2/g.

Theadsorptioncapacityofsilver-ionloadedactivatedcarbonforDBTindieselfuelisshowninFigure2.Theadsorptioncapacityofthesilver-ionloadedactivatedcarbonishigherthanthatoftheactivatedcarbon.Themaximumadsorptioncapacityofthesilver-ionloadedactivatedcarbonforDBTis10.63mg/g.TheLangmuirandFreundlichisothermswereusedtomodeltheadsorptionbehaviorofDBTontosilver-ionloadedactivatedcarbon.TheLangmuirisothermmodelfitstheexperimentaldatabetterthantheFreundlichisothermmodelwithacorrelationcoefficientof0.997.

Discussion

Thesilver-ionloadedactivatedcarbonshowedahigheradsorptioncapacityforDBTcomparedtoactivatedcarbon.Thiscanbeattributedtothepresenceofsilverionsontheactivatedcarbonsurface,whichcanactasLewisacidsitesandenhancetheinteractionbetweentheadsorbentandtheadsorbate.Thesilverionscanalsoactaselectronacceptorsandformcomplexeswiththesulfur-containingmoleculesinDBT.

TheBETsurfaceareaofthesilver-ionloadedactivatedcarbonislowerthanthatoftheactivatedcarbon.Thiscanbeattributedtothedepositionofsilverionsontheactivatedcarbonsurface,whichmayfillsomeoftheporesandreducethesurfacearea.However,themicroporoussurfacearea,whichisimportantforadsorptionofDBT,isnotsignificantlyaffected.

TheLangmuirisothermmodelwasfoundtobethebestfittotheexperimentaldata.ThisindicatesthattheadsorptionofDBTontosilver-ionloadedactivatedcarbonisamonolayer,homogeneousprocess.Themaximumadsorptioncapacityofthesilver-ionloadedactivatedcarbonforDBTishigherthanthatreportedforotheradsorbentssuchaszeoliteandactivatedcarbon.

Conclusion

Inconclusion,theresultsanddiscussionofthisstudydemonstratethatsilver-ionloadedactivatedcarbonisaneffectiveadsorbentfortheremovalofdibenzothiophenefromdieselfuel.ThesilverionsontheactivatedcarbonsurfaceenhancetheadsorptioncapacitythroughLewisacid-baseinteractionsandcomplexation.TheLangmuirisothermmodelfitstheexperimentaldatabetterthantheFreundlichisothermmodel.Themaximumadsorptioncapacityofthesilver-ionloadedactivatedcarbonforDBTishigherthanthatofotheradsorbents.Thisstudyprovidesvaluableinformationonthedevelopmentofeffectiveadsorbentsfortheremovalofsulfur-containingcompoundsfromdieselfuel.Chapter5:ConclusionandFutureRecommendations

Introduction

Thischapterpresentstheconclusionandfuturerecommendationsforthestudyonadsorptionofdibenzothiophene(DBT)fromdieselfuelusingsilver-ionloadedactivatedcarbon.

Conclusion

Thestudyevaluatedtheadsorptioncapacityofsilver-ionloadedactivatedcarbonfortheremovalofDBTfromdieselfuel.Theresultsshowedthatthesilver-ionloadedactivatedcarbonhadhigheradsorptioncapacitycomparedtoactivatedcarbon.TheBETsurfaceareaofthesilver-ionloadedactivatedcarbonwasfoundtobelowerthanthatofactivatedcarbon,butthemicroporoussurfacearea,whichisimportantforadsorptionofDBT,wasnotsignificantlyaffected.TheLangmuirisothermmodelwasfoundtobeabetterfittotheexperimentaldatathantheFreundlichisothermmodel.

Thestudydemonstratedthatsilver-ionloadedactivatedcarbonisaneffectiveadsorbentfortheremovalofDBTfromdieselfuel.ThepresenceofsilverionsontheactivatedcarbonsurfaceenhancestheadsorptioncapacitythroughLewisacid-baseinteractionsandcomplexation.Themaximumadsorptioncapacityofthesilver-ionloadedactivatedcarbonforDBTwashigherthanthatreportedforotheradsorbentssuchaszeoliteandactivatedcarbon.

FutureRecommendations

Thestudyprovidesvaluableinsightsintothedevelopmentofeffectiveadsorbentsfortheremovalofsulfur-containingcompoundsfromdieselfuel.Thefollowingaresomeofthefuturerecommendations:

1.OptimizationofConditions:Thestudywascarriedoutunderoptimizedconditions.Futureresearchcaninvestigatetheeff