邻菲罗啉对蒙脱石吸附镍离子性能影响

利用镍离子能与邻菲罗啉反应生成螯合物的性质,研究了加与未加邻菲罗啉条件下,蒙脱石对金属镍离子的吸附行为,考察了镍离子浓度、吸附时间、温度和溶液pH值等因素对吸附性能的影响.结果表明:加入邻菲罗啉后,蒙脱石对镍的螯合离子的吸附量明显增大;吸附平衡时间约为120min;蒙脱石对Ni(phen)n]2+的吸附性基本不受pH值的影响.动力学研究表明该吸附过程符合准二级反应动力学模型,吸附量随温度升高而增大.二级动力学参数证明加入邻菲罗啉可显著提高蒙脱石对Ni2+的吸附性.蒙脱石对简单Ni2+的吸附符合Langmuir的单层吸附等温式;而蒙脱石对镍的螯合离子的吸附则符合Freundlich等温式.蒙脱石对Ni2+和Ni(phen)n]2+的吸附均为自发、吸热和更无序的;XRD及FTIR研究表明,蒙脱石对Ni(phen)n]2+的吸附以层间的物理吸附为主.

Influence of 1,10-phenanthroline on adsorption behaviour of Ni(II) onto montmorillonite

This study explored the adsorption behaviour of Ni(II) from aqueous solutions onto Na-montmorillonite in the presence of 1,10-phenanthroline, forming complex cations with Ni(II). Batch adsorption studies were carried out with various Ni(II) concentrations, pH, agitation time and temperature. The results showed that the adsorption capacity of Ni(II) complex cations onto montmorillonite obviously increased in the presence of 1,10-phenanthroline. Montmorillonite has larger adsorptive capability of ²⁺ than that of Ni(II). The kinetics of Ni(II) and ²⁺ uptake by montmorillonite followed the pseudo-second-order chemisorption mechanism. Equilibrium was achieved within 120 min and the adsorption of ²⁺ was pH independent. The suitability of Langmuir and Freundlich adsorption models to the equilibrium data was investigated. The adsorption of Ni(II) and ²⁺ was well described by the Langmuir isotherm model and Freumdlich isotherm model, respectively. Moreover, the results suggested that the adsorption of Ni(II) and ²⁺ onto montmorillonite was all spontaneous, endothermic and more random. The XRD and FTIR studies indicated that the physical adsorption process was the main interaction between montmorillonite and ²⁺.