河流沉积物对典型重金属污染物的吸附-解吸研究

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1、describedbybothLangmuirandFreudlichequations,especiallyLangmuirequation.TheorderofpartitioncoefficientsbetweensedimentsandwaterforheavymetalsareCu＞Pb＞Cd＞Zn＞Ni＞Cr.ThereforeCuandPbtransportintosedimentsmoreeasily.ThepHonadsorptionquantityofchangeshadamajorinfluence.WiththepHincreasing,adsorptionofmet

2、alionshadobviouslyincreased.TheorderofsensitivitytopHisNi、Cd＞Zn、Cu＞Pb、Cr.Withthedecreaseofsedimentparticlesize,theamountofadsorptionofheavymetalswasincreased.(5)Asthetimewenton,thedesorbingcapalityofheavymetalsinsedimentswasincreased,eventuallyreachequilibrium.Thedesorptionprocessofheavymetalsinsed

3、imentscanbedividedintofastandslowreactionstage,anditmoreaccordswiththeElvichequation,indicatingthattheheavymetalsdesorptionprocessisheterogeneousdiffusion.DesorptionrateofheavymetalsfromfasttoslowisCr＞Cu＞Ni＞Pb＞Zn＞Cd.Withthereactiontemperaturerised,thedesorbingcapalitywasnosignificantchange,butthede

4、sorptionrateincreasedslightly.InadditionCr,therestoffiveheavymetalsdesorbingcapacitydecreasedwithpHincreased,changesignificantly.Withthedecreaseofsedimentparticlesize,thedesorbingcapalityofheavymetalsisalsoreduced.MengqiHe(EnvironmentalEngineering)SupervisedbyGangXue,PinGaoKEYWORDS:sediment;heavyme

5、tal;existenceform;adsorption;desorptionV万方数据目录摘要.......................................................................................................................................................IABSTRACT...........................................................................................

6、.............................................IV第一章绪论...........................................................................................................................................11.1研究背景....................................................................................................

7、...............................11.2底泥沉积物中重金属概述.....................................................................................................21.2.1重金属定义................................................