苯或甲苯对粒状铁还原三氯乙烯及其中间产物顺式二氯乙烯的影响

31720107ENVIRONMENTALSCIENCEVol.31No.7Jul.2010123111.1000832.1000853.430010、、BTEXFe0-PRBFe0-PRBBTEX.TCE.1～2mg·L－1TCE2mg·L－1TCE15.1%18.5%cis-12-DCE4.5%42.8%.Fe0-PRBTCETCETCEcis-12-DCEcis-12-DCE2～75μg·L－1cis-12-DCEFe0-PRBFe0-PRBTCEcis-12-DCEBTEXFe0-PRB.X703.1A0250-3301201007-1526-072009-08-072009-09-2712120106346078632007AA06A4101971～[e-mail]eonReductiveDechlorinationofTrichloroethyleneandItsDaughterProductcis-12-DichloroethylenebyGranularIronLIUYu-long12XIAFan3LIUFei1CHENHong-han11.BeijingKeyLaboratoryofWaterResourcesandEnvironmentalEngineeringChinaUniversityofGeosciencesBeijingBeijing100083China2.ResearchInstituteofSafetyandEnvironmentalTechnologyChinaNationalPetroleumCorporationBeijing100085China3.YangtzeValleyWaterEnvironmentMonitoringCenterWuhan430010ChinaAbstractMixedplumescontainedchlorinatedsolventsandpetroleumhydrocarbonswhichmainlyreferstoBTEXbenzenetolueneethylbenzeneandxylenesingroundwatercanberemediatedbysequentialunitscombinedanironpermeablereactivebarrierFe0-PRBwithananoxicwall.IndesignoftheFe0-PRBitshouldbetakenintoaccountthenecessityofalteringthewidthoftheironcellinthepresenceofBTEX.Threecolumnexperimentswereconductedtoevaluatetheeffectsofbenzenetolueneonthelong-termperformanceofreductivedechlorinationoftrichloroethyleneTCEbygranulariron.TheresultsshowedthatthekineticsofTCEattheinitialconcentrationof2mg·L－1moreorlessreductionwasaccordedwithpseudofirst-ordereveninthepresenceofbenzeneortolueneatabout1-2mg·L－1respectively.TheexistenceofbenzeneandtolueneinhibitedtheremovalofTCEby15.1%and18.5%respectivelyhoweverthepresenceofbenzeneslightlyincreasedcis-12-DCEreductionrateby4.5%andthepresenceoftolueneincreasedcis-12-DCEreductionrateby42.8%.Theinhibitionofbenzeneandtolueneotherthanmineralprecipitateswasnotoneofthedecisivefactorsinthelong-termperformanceofanFe0-PRBinadditionthekindsofchlorinateddaughterproductsofTCEinthepresence/absenceofbenzeneortoluenewereidenticalandcis-12-dichloroethylenecis-12-DCEthemajorintermediatefirstlybrokethroughfromallthe3columnsatconcentrationsabout2-75μg·L－1indicatingthatdesigningthewidthofanFe0-PRBshouldbebasedonthehydraulicresidencetimeofcis-12-DCE.InconclusionifonlyconsideringtheTCEremedialgoalsanddisregardingtheeffectsofcis-12-DCEonBTEXbiodegradationdowngradienttheFe0-PRBtheresultssuggestedthatitshouldbenotnecessarytoincreasethewidthoftheironcellforconstructingsequentialpermeablereactivebarriersSPRBstorescueTCE-andBTEX-contaminatedaquifers.KeywordsgranularironbenzenetoluenetrichloroethyleneTCEcis-12-dichloroethylenecis-12-DCEsequentialpermeablereactivebarrierSPRB、、BTEX1～6ironpermeablereactivebarrierFe0-PRB7BTEX.BTEXFe0-PRB.Dries7、perchloroethylenePCEtrichloroethyleneTCEPCE50%TCE.89PCEPCEPCE.BTEXTCE.TCE、TCEcis-12-dichloroethylenecis-12-DCEFe0-PRBTCEBTEX.11.1Agilent6890/5973NDB-VRX60m×0.25mm×1.4μmHPTekmar3100.BT100-1L6.2000mg·L－1ChemService542000mg·L－1Supelco.TCE、、.1.20～402.03m2·g－1BET2.11/mg·L－1Table1Componentsofthegroundwater/mg·L－1K+Na+Ca2+Mg2+Fe3+Fe2+Cl－NO－3SO2－4HCO－3pH21.9218.0173.9633.300.21ND47.29ND69.78283.67.781221/%Table2Chemicalcompositionofthegranulariron/%FeCSiZnMnCuCrNi91.923.412.780.0131.180.0430.0320.02611.245.0cm4.2cm.71.0、3.5、8.5、13.5、18.5、28.538.5cm.∶=1∶1.porevolumePV..1.33.102～3d1mg·L－1.1.2.Fe0-PRB3.1Fig.1Schematicofthecolumnsetup、、TCE9.232d.7251313Table3Operationparametersofthecolumns/g/mL/%/m·d－11/μg·L－1TCETC119521234.20.511800——TB119820933.50.511860960—TT119520532.80.511910—9201“—”22.1TCETCE－dcTCEdt=kcTCE11lnc0TCEcTCE=kt2cTCETCEmg·L－1c0TCETCEmg·L－1kh－1th.lnc0TCEcTCEtkTCEkobsh－1.3TCE2mg·L－1TBTT1～2mg·L－1.、、、TCETCEkobsR24250PVkobsTCE.2.2TCE4TCETable4Observedfirst-orderTCEremovalrateconstantsinthepresentofbenzeneortoluene10PV20PV34PV45PV60PV80PV100PV120PV150PV200PV250PVTCkobs/h－10.83410.80830.76370.69580.62630.53490.65600.81160.87720.59230.4085R20.97980.97870.99330.99600.99280.99730.98590.97760.99270.99790.9869TBkobs/h－10.74080.70650.61080.58090.45510.49200.57570.79400.85790.59030.4418R20.98590.99530.99680.99120.99620.98590.97230.99050.99720.99210.9932TTkobs/h－10.72630.67790.60010.53150.37480.46620.47860.70890.65810.53630.4535R20.98960.98930.98570.97930.98220.98220.98830.98250.98370.99010.9676TCEkobs2.45PV20℃kobsTCTCEkobsTBTCE+TTTCE+kobsTC.60PVkobsTTkobs120PV150PVTCTBkobsTCkobs.150PV3kobs250PVTCEkobs.23kobsTCE32℃TCE.45PV4TCETCE15.1%18.5%.2TCEFig.2KineticeffectsofbenzeneortolueneonremovalofTCE825172.3cis-12-DCEGC/MSTCEcis-12-DCE、11-11-dichloroethylene11-DCE、vinylchlorideVCtrans-12-dichloroethylenetrans-12-DCE.60PV20℃TCETCE.334PVTCETC、TBTTTCE10.77、11.2210.85μmol·L－1.3cis-12-DCE13.5cm6.48hcis-12-DCEcis-12-DCE0.38～0.60μmol·L－137～58μg·L－111-DCEVC.TCETCETCE11cis-12-DCE11-DCEtrans-12-DCE.①3②TCEtrans-12-DCEcis-12-DCE11trans-12-DCE11-DCEcis-12-DCE22%12③trans-12-DCEcis-12-DCE13～15④TCE2mg·L－114TCE100mg·L－1trans-12-DCE.cis-12-DCETCETCE11cis-12-DCETCEVCβ-TCEk→1cis-12-DCEk→2VC+Ethyne33TCEFig.3ProfilesofTCEanditschlorinatedintermediates’concentrationsalongwiththecolumnsk1cis-12-DCEh－1k2cis-12-DCEh－1.cis-12-DCEth4.dcci