Adsorption behavior of U(VI) on doped polyaniline: the effects of carbonate and its complexes
Adsorption behavior of U(VI) on doped polyaniline: the effects of carbonate and its complexes
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DOI：
10.1515/ract-2017-2865
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发表时间：
2018-06
影响因子：
1.8
通讯作者：
Jun Liu;Changsong Zhao;Guoyuan Yuan;Feize Li;Jijun Yang;J. Liao;Yuanyou Yang;Ning Liu
中科院分区：
文献类型：
--
作者：
Jun Liu;Changsong Zhao;Guoyuan Yuan;Feize Li;Jijun Yang;J. Liao;Yuanyou Yang;Ning Liu
在碳酸盐岩缓冲海水或盐湖卤水中，铀配合物主要有U(VI)-CO3和Ca/Mg-U(VI)-CO3。采用间歇吸附实验研究了碳酸盐及其配合物对掺杂聚苯胺（PANI）吸附U（VI）的影响。当U(VI)-CO3络合物在水溶液中占主导地位时，U（VI）在掺杂聚苯胺上的吸附在接触时间30 min内达到平衡。拟二级模型和Langmuir等温线模型表明，吸附是通过单层化学吸附在均匀表面发生的。此外，pHinitial、可溶性碳酸盐、钙和镁浓度的增加可以抑制铀的吸附过程。弱碱性条件下的吸附机制主要涉及铀阴离子在含氮官能团上的吸附，而不是在掺杂聚苯胺表面阴离子交换活性位点上的吸附，而U(VI)-CO3配合物比Ca/Mg-U(VI)-CO3配合物具有更大的亲和力。本研究结果对于盐湖盐水或海水中铀资源的提取以及弱碱性溶液环境中铀吸附行为的预测具有重要意义。
Abstract In carbonate-buffer seawater or salt lake brines, three main uranium complexes, U(VI)-CO3 and Ca/Mg-U(VI)-CO3 complexes had been highlighted so far. In this paper, the effects of carbonate and its complexes on U(VI) adsorption onto doped polyaniline (PANI) were investigated using batch adsorption experiments. The adsorption equilibrium of U(VI) on doped PANI was reached within 30 min of contact time when U(VI)-CO3 complexes dominated the aqueous chemistry. Pseudo-second order and Langmuir isotherm models indicated that adsorption occurred on the homogeneous surface via monolayer chemisorption. Moreover, the increase in pHinitial, dissolved carbonate, calcium and magnesium concentrations could suppress the uranium adsorption process. The adsorption mechanisms under the weakly basic conditions were primarily involved in uranium anion species adsorption on nitrogen-containing functional groups instead of the anion exchange reactive sites on the doped PANI surface sites, whereas the U(VI)-CO3 complexes had a greater affinity than the Ca/Mg-U(VI)-CO3 complexes. The findings of this study are significant for the extraction of uranium resources from salt lake brines or seawater and for the prediction of uranium adsorption behaviors in weakly basic solution environments.