CEJ2832016412419Degradationofchlortoluron

See discussions, stats, and author profiles for this publication at: of chlortoluron during UVirradiation and UV/chlorine processes andformation of disinfection by-products insequential...Article · July 2015DOI: 10.1016/j.cej.2015.07.074CITATIONS3READS427 authors, including:Yi-Li LinNational Kaohsiung First University of Scienc…38 PUBLICATIONS 392 CITATIONS SEE PROFILEBin XuTongji University73 PUBLICATIONS 974 CITATIONS SEE PROFILENai-Yun GaoTongji University315 PUBLICATIONS 3,674 CITATIONS SEE PROFILEAll content following this page was uploaded by Yi-Li Lin on 08 March 2016.The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original documentand are linked to publications on ResearchGate, letting you access and read them immediately.DegradationofchlortoluronduringUVirradiationandUV/chlorineprocessesandformationofdisinfectionby-productsinsequentialchlorinationZi-BoGuoa,Yi-LiLinb,BinXua,⇑,HeHuanga,Tian-YangZhanga,Fu-XiangTiana,Nai-YunGaoaaStateKeyLaboratoryofPollutionControlandResourcesReuse,KeyLaboratoryofYangtzeWaterEnvironment,MinistryofEducation,CollegeofEnvironmentalScienceandEngineering,TongjiUniversity,Shanghai200092,PRChinabDepartmentofSafety,HealthandEnvironmentalEngineering,NationalKaohsiungFirstUniversityofScienceandTechnology,Kaohsiung824,Taiwan,ROChighlightsDegradationpathwaysofchlortoluronduringUVirradiationandUV/chlorinationwereproposed.KineticmodelswereestablishedforchlortolurondegradationduringUV/chlorineprocess.ChlortoluronmineralizationdecreasedwithincreasingpHduringUV/chlorineprocess.EnhancedformationofDBPsweredetectedduringUV/chlorineprocess.graphicalabstractarticleinfoArticlehistory:Received14May2015Receivedinrevisedform9July2015Accepted21July2015Availableonline29July2015Keywords:UV/chlorineprocessUVirradiationChlortolurondegradationDisinfectionby-products(DBPs)WatertreatmentKineticsabstractThedegradationkineticsandpathwaysofchlortoluronduringUVirradiationandUV/chlorineprocessaswellastheformationofdisinfectionby-products(DBPs)afterpost-chlorinationwereinvestigatedinthisstudy.Thequantumyieldofchlortoluronwascalculatedas0.0258moleinstein1andtheeffectofsolu-tionpHwasnegligibleduringUVirradiation.Ontheotherhand,thedegradationrateofchlortolurondur-ingUV/chlorineprocesswassignificantlypromotedatacidicconditionsaswellashighchlorinedosesandUVintensity.UVirradiationandUV/chlorinationofchlortoluronbothfollowedthepseudo-firstorderreactionkinetics,butUV/chlorineprocessismoreefficientthanUVirradiationwiththereactionratecon-stantbetweenchlortoluronandOHradicalsdeterminedas(2.18±0.83)109M1s1.Themineraliza-tionofchlortoluronwasconsiderablyincreasedwithincreasingchlorinedoseanddecreasingpHduringUV/chlorineprocess.ThedegradationpathwaysofchlortoluronduringUVirradiationandUV/chlorineprocesseswereproposedaccordingtotheidentifiedintermediates.TheformationofcarbonaceousDBPs(C-DBPs)andnitrogenousDBPs(N-DBPs)duringdirectchlorinationandpostchlorinationofUVirradiationandUV/chlorineprocesseswereinvestigatedaswell.MoreDBPprecursorswereformeddur-ingUV/chlorineprocesscomparedtodirectchlorinationandUVirradiation,whichdeservesextensiveconcernsindrinkingwatertreatmentprocesses.2015ElsevierB.V.Allrightsreserved.2015ElsevierB.V.Allrightsreserved.⇑Correspondingauthor.Tel.:[phone].E-mailaddress:[e-mail](B.Xu).ChemicalEngineeringJournal283(2016)412–419ContentslistsavailableatScienceDirectChemicalEngineeringJournaljournalhomepage:[1].Chlortoluronisakindofphenylureaherbicidesthatiswidelyusedinpre-andpost-emergencecontrolofmeadowgrass,annualgrass,wildoatsandbroadleafweedsincerealcrops[2].However,thetoxicityandpossiblecarcinogenicityofphenylureaherbicideshavebeenshownonhumansandwildlifeevenatlowconcentrations[3],whichconstitutesanimportantenvironmentproblemnowadays.Thedegradationrateofchlortoluronisfairlyslowwiththehalf-lifeover200dinwaterand30–40dinsoil[4]duetoitschemicalstabilityandresistancetoheat.Thedegradationofchlortoluronisprimarilythroughmicrobialtransformationandphotochemicalprocesses,whichcouldleadtoonlypartialdegradationandtheaccumulationofsomehazardousproductsintheenvironment[5].Therefore,WorldHealthOrganization(WHO)establishedamaximumconcentrationofchlortoluronas30lg/Lintheguideli-nesfordrinkingwaterquality[6].Chlorineisthemostwidelyuseddisinfectantthroughouttheworldtocontroltaste,color,odorandthesubsequentgrowthofmicrobialbacteriainwater[7].Comparedwithchlorination,ultraviolet(UV)irradiationisaphysicaltreatmentthatleavesnoresidualdisinfectingability[8].Therefore,UVdisinfectionisalwaysfollowedbyotheroxidizingprocessessuchaschlori-nation,chloraminationandH2O2additiontoprovideappropri-atedisinfectingpowerindrinkingwaterinthedistributionsystems[9].Thecomb