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1,1,2(1., 310029;2.,):,Pd-Cu/γ-Al2O3,.:,N2,80%.、pH、H2、,H2;,,,.,.:;;;;;:TU991.2 :A :0250-3301(2003)04-04-0109:(1971～),,,,,.:2002-06-27;:2002-09-02ChemicalDenitrificationofNitratefromGroundwaterZhangYan1,ChenYingxu1,ChenGuanghao2(1.DepartmentofEnvironmentalEngineering,ZhejiangUniver-sity,Hangzhou 310029,China;2.DepartmentofCivilEngineering,HongkongUniversityofScience&Technology,Hongkong,China)Abstract:BatchexperimentsforcatalyticreductionofnitratefromgroundwaterwithPdand/Cucatalystswereconduct-ed.ItwasfoundthatPd-Cucombinedcatalystsataratioof4canmaximizethenitratereductionintonitrogen;above80%totalnitrogenremovalefficiencywasrealizedinthisstudy.Itwasalsofoundthatthecatalyticactivitywasaffectedbytheamountsofcatalysts,hydrogenflowrateandpressure,theinitialconcentrationofnitrate.Withanincreasingintheamountofthecatalysts,bothnitriteandammoniaintermediatescanbekeptatalowlevel.Ahighflowrateandpressureofhydrogenwasinfavorofthecatalyticreductionofnitrate,butnotbenefitfortheselectivity.Thecatalyticreductionfollowedafirstorderkineticsintermoftheinitialnitrateconcentration.Keywords:nitrate;ammonia;groundwater;catalyticreduction;chemicaldenitrification ,,.,、,[1～3].,[4],“”[5].WHOUSEPANO3-N10mg/L[6],20mg/L.[7](、、)[8,9].,,,,;,,,.,,.,,,.1 24420037 ENVIRONMENTALSCIENCEVol.24,No.4July,2003DOI:10.13227/j.hjkx.2003.04.0211 Fig.1 Experimentalsetup1.1 ,PdCl2Cu(NO3)2Pd、Cu,,,:,,,100℃;350℃2h;NaBH4,,XPS,γ-Al2O3Pd-Cu;,.2PdCl2+NaBH4+3H2O=2Pd+NaCl+3HCl+B(OH)3+2H22Cu(NO3)2+NaBH4+3H2O=2Cu+NaNO3+B(OH)3+2H2+3HNO31.2 1.5L(1).900mL2g,300r/min,H20.5h,1000mg/LNaNO3100mL,1000mL,NaNO3100mg/L.25℃,H2.,HClpHpH.,NO-3、NO-2、NH+4.pHS-3CpH;Dionex-120NO-3、NO-2,NH+4722λ=420nm.2 :,NO-3NH3-N.,gminNO-3NH3-N,.NH3-N,N2.2.1 2Pd.,Pd,,240min,40%.,,46.5%.,Pd-Cu,,Pd20,80%(3).,2、3:,PdNO-2,Pd-Cu,NO-2.NO-3,,PdNO-3,NO-2,.2 NO-3(Pd/γ-Al2O3)Fig.2 TemporalprofilesofnitrateconsumptionandammoniumionyieldforPd/γ-Al2O32.2 4,,,110 243 NO-3(Pd-Cu/γ-Al2O3)Fig.3 TemporalprofilesofnitrateconsumptionandammoniumionyieldforPd-Cu/γ-Al2O3.4,,,,1h,.:,,,Pd,Pd,,.4 NO-3Fig.4 EffectofvariousamountofPd-Cu/Al2O3onnitratereduction,,.(1),,NOx.NOxNOx,N—N,N2;NOxH2,N—H,H2NH+4.NOxH2N2.,,H2,NO-2PdN2,,N2.:NO-3※NO-2※(NO)※N2O※N2NO-2※(NO)※NH+4(1)2.3 (5),,NO-2,,,,R20.998.:,,.5 Fig.5 Thecurveofinitialratevs.initialconcentration2.4 H2,H2、,H2100～300mL/min,H20.1～0.2MPa.6、7:H21114 ,NH3-N.H2,,,,;,,,.,,,.,H2,NO-3H2,NH3-N,.6 H2NO-3Fig.6 EffectofthefluxofH2onnitrateremovalactivityandammoniayieldforPd-Cu/γ-Al2O37 H2NO-3Fig.7 EffectofthepressureofH2onnitrateremovalactivityandammoniayieldforPd-Cu/γ-Al2O33 (1)Pd(5%)-Cu(1.25%)/γ-Al2O3,80%.(2),.(3).,H2,,.H2,,,.(4),,,.:1 CardSchubert,MartySKanarek.PublicResponsetoEle-vatedNitrateinDrinkingWaterWellsinWisconsin.ArchivesofEnvironmentalHealth,1999,54(4):242～247.2 BelgiornoV,NapollRM.Groundwaterqualitymonitoring.WaterScienceTechnology,2000,42(1-2):37～41.3 ,..,1999,7(4):41～43.4 SpaldingRF,ExnerME.Occurrenceofnitrateinground-water———areview.J.Environmentquality,1993,22:392～402.5 WardMH,MarkSD,CantorKP.Drinkingwaternitrateandtheriskofnon-Hodgkin'slymphoma.Epidemiology,1996,7:465～471.6 U.S.EnvironmentalProtectionAgency(1995).Drinkingwaterregulationsandhealthadvisories.OfficeofWater,Washington,DC.7 WesleyTDorshelmer,CharleesBDrewry,DavidPFritsch,DainEWilliants.Removingnitratefromgroundwater.Wa-ter/Engineering&Management,1997,12:20～24.8 OelMFlere,TianCZhang.NitrateRemovalwithSulfur-LimestoneAutotrophicDenitrificationProcesses.J.ofEnvi-ronmentalEngineering,1999,125(8):721～729.9 KurtM,DunnIJ,BourneJR.BiologicaldenitrificationofdrinkingwaterusingautotrophicorganismswithH2inaflu-idized-bedbiofilmreactor.BiotechnologyandBioengineering,1987,29:493～501.112 24