Adsorption-of-roxarsone-from-aqueous-solution-by-multi-walled-carbon-nanotubes-in-press

Adsorptionofroxarsonefromaqueoussolutionbymulti-walledcarbonnanotubesJianglinHua,ZilinTonga,ZhenhuHua,b,⇑,GuoweiChena,b,⇑,TianhuChencaSchoolofCivilEngineering,HefeiUniversityofTechnology,Hefei230009,ChinabInstituteofWaterTreatmentandWastesReutilization,SchoolofCivilandHydraulicEngineering,HefeiUniversityofTechnology,Hefei230009,ChinacSchoolofResourcesandEnvironmentalEngineering,HefeiUniversityofTechnology,Hefei230009,ChinaarticleinfoArticlehistory:Received1January2012Accepted23March2012AvailableonlinexxxxKeywords:AdsorptionisothermsKineticsMWCNTsRoxarsoneabstractRoxarsone,anorganoarseniccompoundservingasacommonfeedingadditiveinpoultryindustry,bringsaboutpotentialriskofthetoxicinorganicarsenatecontaminationinambientenvironment.Currentunderstandinginthedynamicsofroxarsoneremovalandthedeterminingenvironmentalprocessesremainsunclear,thusrestrictstheprogressinroxarsone-contaminatedwastewatertreatment.Inthisstudy,theadsorptionofroxarsoneonmulti-walledcarbonnanotubes(MWCNTs)wasinvestigated.TheadsorptionofroxarsoneonMWCNTsdecreaseddramaticallywithincreasingpHfrom2.0to11.7anddecreasedsignificantlywithincreasingionicstrengthfrom0to1.0mol/LKCl.ItwasfoundthatthesorptionisothermsofroxarsoneonMWCNTswerenonlinear,whichcanbewelldescribedaccordingtotheFreundlichandPolanyi–Manesmodels.ThermodynamicanalysisindicatesthattheadsorptionofroxarsoneonMWCNTsisanexothermicandspontaneousprocess.SorptionsiteenergyanalysisrevealsadistributionofsorptionenergyandtheheterogeneousadsorptionsitesofroxarsoneonMWCNTs.Thedynamicadsorptionwithcolumnshowsthepotentialofthepracticalapplicationfortheroxarsone-con-taminatedwastewatertreatmentbyMWCNTs.TheFTIRanalysisindicatesthatEDAinteractionandelec-trostaticrepulsionmightbethedominantmechanismsfortheadsorptionofroxarsoneonMWCNTs.�2012ElsevierInc.Allrightsreserved.1.IntroductionRoxarsone(3-nitro-4-hydroxyphenylarsonicacid)hasbeenusedwidelyinpoultryindustryfordecadestocontrolcoccidialintestinalparasitesandtoenhancefeedefficiency[1,2].Mostoftheaddedroxarsoneina