锆基MOFs材料Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)的吸附性能研究

Adsorption of Th(Ⅳ) and Ce(Ⅳ) on Zirconium Based Metal-organic Framework Zr-CAU-24

  • 摘要: 本文采用溶剂热法合成了微孔结构的锆基金属-有机框架(MOFs)材料Zr-CAU-24,该材料比表面积为1 610 m2/g。对所合成的Zr-CAU-24进行了热重分析(TGA)和辐照稳定性测试,考察了接触时间、初始pH值等对Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)吸附性能的影响,并探讨了Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)吸附过程的动力学和热力学。结果表明:Zr-CAU-24具有良好的热稳定性和辐照稳定性;准二级动力学模型为Th(Ⅳ)和Ce(Ⅳ)在Zr-CAU-24上的吸附过程提供了很好的解释,即该过程为化学吸附过程;Zr-CAU-24活性位点分布均匀,为单层吸附;混合金属离子溶液吸附研究发现,Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)具有吸附选择性。

     

    Abstract: In this paper, zirconium based metal-organic frameworks (MOFs) Zr-CAU-24 was successfully prepared by using solvothermal method, which was one kind of zirconium based MOFs. Zr-CAU-24 has nanoporous structure with BET specific surface area of 1 610 m2/g. Thermogravimetric analysis (TGA) and irradiation stability test were conducted. Taking Zr-CAU-24 as adsorbent, the adsorption characteristics of Th(Ⅳ) and Ce(Ⅳ) on Zr-CAU-24 were investigated through static adsorption experiments. The effects of contact time, initial pH on Th(Ⅳ) and Ce(Ⅳ) adsorption by Zr-CAU-24 were investigated respectively, and the kinetics and thermodynamics were investigated. The results indicate that Zr-CAU-24 has good thermal stability and irradiation stability. The quasi-second-order model provides a good explanation for the adsorption process of Th(Ⅳ) and Ce(Ⅳ) on Zr-CAU-24, which is a chemical adsorption process. The active site of Zr-CAU-24 is evenly distributed, and the adsorption is a single layer adsorption. Through the study of selective adsorption of mixed metal ions on Zr-CAU-24, it is found that Zr-CAU-24 has the adsorption selectivity for Th(Ⅳ) and Ce(Ⅳ).

     

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