【摘要】 本文系统地研究了Fe2 O3·nH2 O(am) -Cd(Ⅱ )固 -液界面吸附过程的各种性质 ,并从吸附等温线 ,动力学和热力学的角度探讨了其吸附机理 ,着重讨论了Cd(Ⅱ )的吸附对Fe2 O3·nH2 O(am)表面电性质的影响。更多还原

【Abstract】 This paper deals with the specific adsorption of Cd(Ⅱ) on Fe 2O 3·nH 2O(am) systematically.The mechanism of the reaction is studied in various respects including adsorption isotherm,kinetic,thermodynamics and electrophoresis.The effect of Cd(Ⅱ) adsorption on the electric properties of the oxide surface has been essentially investigated.From the experimental results,we come to the following conclusions:(1)The percentage adsorption -pH curves for Fe 2O 3·nH 2O(am)-Cd(Ⅱ) suspension are “S shaped”,which show that the dominant adsorbing species are [Cd 2+ ] and [CdOH +](2) The typical stepwise adsorption isotherms are presented at various pH’s,which result from the different types of hydroxy1 groups of hydrous iron oxide surface.(3)The adsorption of Cd(Ⅱ) on Fe 2O 3·nH 2O(am)is specific.(4)The rate of reaction is controlled by the diffusion Cd(Ⅱ) through the reacted layer.(5)According to the experimental results,the mechanism of Cd(Ⅱ) adsorption at Fe 2O 3·nH 2O(am)-water interface in whole pH region is:exchange_adsorption /complexation_precipitation/diffusion.更多还原