【摘要】 研究了不同p H值、初始Cr3+浓度、温度、反应时间等条件下蒙脱石对Cr3+及螯合物[Cr(phen)3]3+的吸附行为,探讨了电动电位变化与吸附性能的关系。结果表明:蒙脱石吸附[Cr(phen)3]3+性能明显优于吸附Cr3+的性能,其主要原因在于蒙脱石对[Cr(phen)3]3+的吸附是静电引力及氢键、范德华力共同作用的结果,并且这种吸附能力基本不受介质酸碱性的影响。动力学研究表明两种吸附均符合准二级反应动力学模型。热力学研究表明蒙脱石对[Cr(phen)3]3+和Cr3+的吸附符合Langmuir的单层吸附模型。蒙脱石对[Cr(phen)3]3+和Cr3+的吸附的ΔG均小于零,而ΔH、ΔS都大于零,因此2种吸附均为自发、吸热和更无序的。更多还原

【Abstract】 Ability of metal cation adsorption on montmorillonite depends on electrokinetic properties of colloid suspension. Values of ζ-potential have a prominent effect on its adsorptive behaviour. This study are focuses on the relationship between montmorillonite ζ-potential and adsorption capacity for Cr3+, and the adsorption behaviour of Cr3+ and its chelate cations [Cr(phen)3]3+, forming with 1,10-phenanthroline, from aqueous solutions on montmorillonite. Batch adsorption studies were carried out with various Cr3+concentrations, p H, agitation time and temperature. The results show that the adsorption capacity of Cr3+ on montmorillonite displayed obvious increases in the presence of 1,10-phenanthroline. The adsorption effect for [Cr(phen)3]3+ on montmorillonite includes electrostatic attraction and intermolecular hydrogen bonds; the former interaction is the result of permanent-charge and [Cr(phen)3]3+cations, and the latter interaction is the result of Si-OH hydroxyl and 1,10-phenanthroline. The equilibrium conversion ratio of adsorption reaction increases when [Cr(phen)3]3+ is adsorbed instead of Cr3+, and the adsorption of [Cr(phen)3]3+ is p H independent. It was also found that the kinetics of Cr3+ and [Cr(phen)3]3+ uptake by montmorillonite followed the pseudo-second-order adsorption mechanism. The suitability of Langmuir and Freundlich adsorption models to the equilibrium data was investigated. The adsorption of Cr3+ and [Cr(phen)3]3+ are all well described by the Langmuir isotherm model. Moreover, the results suggest that the adsorptions of Cr3+ and [Cr(phen)3]3+on montmorillonite are both spontaneous, endothermic and more disorderly.更多还原