实验四 CODCr的监测 英语

CODCr,Cucu,COD的定义,COD（ChemicalOxygendemanding）：CODistheamountofoxdizerwhichcomsumedbyreducingsubstanceinthewaterrepresentasOxygenmg/L.Reducingpollutantinthewater：Organics，Inorganic：nitrite，ferroussaltsandsulfide.,COD,TheresultofCODcanbeeffectedbythetypeandconcentrationofoxidant,alsothepH,temperature,time,catalyst.Therefore,thechemicaloxygendemandisaconditionindex.Foraconditionindex：1.followtheproceduresstrictly.2.themethodshouldbeindicatedwiththeresult.,Nationalstandardforsurfacewaterquality.,InternationalCODmethod,BG11914ISO6060,Boilingunderreflux,oxidantreactionreactionreactionmethodcodemediumconditiontime,MicrowaveDigestionmethodforCODCr,Reactionequation：Cr2O72-+14H+6e2Cr3+7H2O（oxidizing）Cr2O72-+14H+6Fe2+2Cr3+6Fe3+7H2O（titrition）Fe2+（indicator）brown（end）ThereactionconditioninthemethodfromGB11914andISO6060isboilingunderflux146148fortwohour.Microwavedigestionfor15mincanachievesameoxidizingefficiencyofboilingunderfluxfor2h,whichwasscientificallyvalidated.,equipment,Microwavedigestionmethod-digestion,Microwavedigestionmethod-titration,微波消解法-数据处理,CODcr浓度（以O2计，mg/L）=式中：C-concentrationofferrousammoniasulfatesolution，mol/L；V0-Titrationvolumeofblank，mL；V1-titrationvolumeofsample，mL；V-Volumeofsample，mL；,Digestionreagent：（0.250N）PotassiumdichromateandMercurysulfateCatalyst:Silversulfateinsulfateacid.DeterminetheconcentrationofferrousammoniasolutionAdd5mlofpotassiumdichromatesolutiontoErlenmeyerflaskaddwaterto45ml,10mlsulfateacidand2dropofindicator.Titratethesolutionwithferrousammoniasolution.Thecolorwillchangefromy