Immobilization of uranium(VI) onto Mg2Al layered double hydroxide: role of key geochemical parameters
Immobilization of uranium(VI) onto Mg2Al layered double hydroxide: role of key geochemical parameters
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DOI：
10.1007/s10967-014-2998-0
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发表时间：
2014-02
影响因子：
1.6
通讯作者：
Donglin Zhao;S. Feng;Han Xuan;Yan Chen
中科院分区：
文献类型：
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作者：
Donglin Zhao;S. Feng;Han Xuan;Yan Chen
采用间歇式技术，研究了Mg2Al层状双氢氧化物（Mg2Al LDH）对水溶液中U（VI）的吸附作用与接触时间、pH、离子强度、土壤黄腐酸（FA）、固含量和温度等水质参数的关系。Mg2Al LDH对U（VI）的吸附依赖于pH值。FA的存在增加了低pH值下U（VI）的吸附，而降低了高pH值下U（VI）的吸附。结果表明，伪二阶模型更适合我们的实验。Langmuir模型比Freundlich和D-R模型更能拟合U（VI）在298、303和313 K三种不同温度下的吸附等温线。根据温度相关吸附等温线计算了吸附过程的热力学参数ΔH°、ΔS°和ΔG°，结果表明，U（VI）吸附是一个自发的吸热过程。结果表明，Mg2Al LDH是一种很有前途的吸附材料，可用于大体积水溶液中铀污染的预富集和分离。
In this study, the sorption of U(VI) from aqueous solution on Mg2Al layered double hydroxide (Mg2Al LDH) was studied as a function of various water quality parameters such as contact time, pH, ionic strength, soil fulvic acid (FA), solid content and temperature by using a batch technique. The sorption of U(VI) on Mg2Al LDH was dependent on pH. The presence of FA increased U(VI) sorption at low pH, whereas decreased U(VI) sorption at high pH. Both kinetics and thermodynamic parameters of the sorption process were evaluated. It was found that the pseudo-second-order model was more suitable for our experiment. The Langmuir model fitted the sorption isotherms of U(VI) better than the Freundlich and D-R model at three different temperatures of 298, 303 and 313 K. The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) were calculated from the temperature dependent sorption isotherms, and the results suggested that U(VI) sorption was a spontaneous and endothermic process. The results demonstrate that Mg2Al LDH is a promising sorbent material for the preconcentration and separation of uranium pollution from large volumes of aqueous solutions.