Amidoxime-functionalized hydrothermal carbon materials for uranium removal from aqueous solution
Amidoxime-functionalized hydrothermal carbon materials for uranium removal from aqueous solution
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DOI：
10.1039/c6ra21986a
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发表时间：
2016-10
期刊：
影响因子：
3.9
通讯作者：
Zhibin Zhang;Zhimin Dong;Ying Dai;Saijin Xiao;Xiaohong Cao;Yunhai Liu;Weihua Guo;M. Luo
中科院分区：
文献类型：
--
作者：
Zhibin Zhang;Zhimin Dong;Ying Dai;Saijin Xiao;Xiaohong Cao;Yunhai Liu;Weihua Guo;M. Luo
一种新型固相萃取剂，以丙烯腈接枝淀粉为前驱体，通过简单、经济、绿色的水热反应制备了肟基功能化水热炭（AO-HTC），用于从核工业废水中选择性分离铀。表征和分析表明，大量的偕胺肟基团（约6.56 mmol g−1）被引入到水热碳的表面上。将AO-HTC应用于水溶液中U（VI）的吸附，由于偕胺肟基团与U（VI）之间的强螯合作用，AO-HTC对U（VI）表现出较高的吸附容量。主要结果如下：（1）在pH = 5.0、T = 298.15 K条件下，AO-HTC在纯U（VI）溶液中的极限饱和容量达到724.6 mg g−1，比水热炭提高了约18.2倍;（2）在pH 1.0 ~ 5.0的较宽范围内，选择性均在60%以上，在弱酸性多阳离子溶液中，选择性最高可达68.92%（3）AO-HTC对铀的吸附是一个pH依赖的吸热自发过程。此外，基于实验表征和化学原理，探讨了AO-HTC表面选择性识别铀酰离子的可能机制。
A novel solid-phase extractant, i.e., amidoxime-functionalized hydrothermal carbon (AO-HTC), has been synthesized, with acrylonitrile grafted starch serving as the precursor, via a simple, economic and green hydrothermal reaction to separate uranium from nuclear industrial effluents selectively. The characterization and analysis indicated that abundant amidoxime groups (approximately 6.56 mmol g−1) were introduced onto the surface of hydrothermal carbon. The AO-HTC was applied to adsorb U(VI) from aqueous solutions and exhibited a high sorption capacity towards U(VI) due to the strong chelation between amidoxime groups and U(VI). The main results are as follows: (1) AO-HTC could reach its limiting saturation capacity of 724.6 mg g−1 at pH = 5.0 and T = 298.15 K in pure-U(VI) solution, which was an improvement of approximately 18.2 times relative to the raw hydrothermal carbon; (2) the selectivity was above 60% for a wide pH range from 1.0 to 5.0, which has not been reported to date, and reached a maximum of 68.92% in a weak acidic multi-cation solution (pH = 2.0); (3) the uranium sorption on the AO-HTC was a pH-dependent, endothermic and spontaneous process. Furthermore, possible mechanisms for the selective recognition of uranyl ions onto the AO-HTC surface were explored based on experimental characterization and chemical rationales.