离子强度、温度、pH和腐殖酸浓度对Th(Ⅳ)在凹凸棒石上吸附的影响

许君政; 范桥辉; 白洪彬; 王冬林; 李湛; 张茂林; 王祥科; 吴王锁

离子强度、温度、pH和腐殖酸浓度对Th(Ⅳ)在凹凸棒石上吸附的影响

Effects of Ionic Strength, Temperature and Humic Substances  Concentration on the Sorption of Th(Ⅳ) to Attapulgite

摘要

摘要: 用静态批式的方法研究了pH值、离子强度、温度和腐殖酸浓度等因素对Th(Ⅳ) 在凹凸棒石上的吸附、解吸的影响。结果表明，pH值对Th(Ⅳ) 在凹凸棒石上的吸附有显著影响，而离子强度对吸附的影响却相对较弱；Th(Ⅳ)在凹凸棒石表面的吸附主要通过内层络合形式进行，而外层络合和离子交换只是微弱的作用；当pH=1.80时，富里酸(FA)和胡敏酸(HA)对吸附亦有促进作用；升高温度有利于Th(Ⅳ) 在凹凸棒石上的吸附，通过热力学数据ΔH， ΔS和ΔG分析发现，Th(Ⅳ) 在凹凸棒石上的吸附是一个吸热且自发的过程；同时，Th(Ⅳ)在凹凸棒石上的吸附过程是不可逆的。

Abstract: The sorption of Th(Ⅳ) on attapulgite was studied as a function of pH, ionic strength, temperature and FA/HA concentration under ambient conditions using batch technique. The results indicate that sorption of Th(Ⅳ) on attapulgite is strongly dependent on pH values, and weakly dependent on ionic strength. The sorption of Th(Ⅳ) is mainly dominated by inner-sphere complexation, whereas outer-sphere complexation and ion exchange have little effect. FA and HA can enhance the sorption of Th(Ⅳ) on attapulgite. Sorption of Th(Ⅳ) increases with increasing temperature. Enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) were calculated from experimental data. The results indicate that the sorption of Th(Ⅳ) on attapulgite is a spontaneous and endothermic process.

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