作　　者： ; ; ;

机构地区： 广东省农业科学院

出　　处： 《土壤学报》 2018年第3期664-672,共9页

摘　　要： 为了解连续性解吸对可变电荷表面吸附性铜离子解吸的影响,研究了高岭石在去离子水和0.1 mol L^(-1) NaNO_3溶液中吸附铜离子后,依次在去离子水以及浓度由低到高的NaNO_3溶液中连续解吸时,离子强度变化对不同pH段铜离子解吸的影响。结果表明:在去离子水中和不同浓度NaNO_3中解吸吸附性铜离子时,pH-解吸分值曲线的变化趋势完全不同。在去离子水中解吸时可出现重吸附现象,而在NaNO_3中解吸时出现解吸峰现象。高岭石pH-铜离子解吸分值曲线的拐点pH与pH吸附有着对应关系,且pH特征与高岭石pH0关系密切。离子强度变化导致的吸附表面电位变化、高岭石边面的诱导水解作用和土壤表面电荷性质随pH升高的变化被认为是导致这些现象的原因。 【Objective】To investigate effect of ionic strength on desorption of Cu（Ⅱ） pre-adsorbed on the surface of a variable charge, kaolinite was put into in de-ionized water or 0.1 mol L-1 NaNO3 solution to adsorbed copper ions first and then into NaNO3 solution varying in concentration from low to high for sequential desorption. 【Method】In this study, kaolinite was pretreated with electrodialysis and then underwent a series of adsorption and desorption tests with varying pH to explore characteristics of copper ions（Cu（Ⅱ）） desorption from the clay mineral.【Result】Similar to the findings of previous studies, the fraction of Cu（Ⅱ） adsorbed by kaolinite increased rapidly from 0.05 to nearly 1 in solutions with pH varying within the set range（pH 3.0～6.3）. Regardless of concentrations of the electrolyte used, all the adsorption fraction curves could be fitted with Fischer equation with the degree of fitting being over 0.999. Also noteworthy, when Cu（Ⅱ） adsorption was carried out separately in de-ionized water and in 0.1 mol L-1 NaNO3 solution, the same in pH, the fraction of Cu（Ⅱ） adsorbed was always higher in de-ionized water than in 0.1 mol L-1 NaNO3 solution, which was attributed to the effect of the electrolyte of high concentration in the solution inhibiting Cu（Ⅱ） adsorption. Results of this experiment demonstrate that firstly, the adsorbed copper ions can be desorbed in de-ionized water, and the fraction of desorbed Cu ion declines with the desorption going on round by round in de-ionized waters the same in pH; secondly, in most cases, when the fraction of desorbed Cu ions approaches near zero, the equilibrium solutions are basically the same in pH（about pH 5.0）; this phenomenon is underatandable when the fraction of readsorbed Cu ions is taken into account; and the last, after the first round of desorption in de-ionized water, the phenomenon of readsorption will begin to appear only when the pH in the solution gets higher than a certain pH value, which mean

关 键 词： 可变电荷表面 铜离子 表面电位 重吸附 特征 解吸峰

领　　域： []