Graphene (rGO) hydrogel: A promising material for facile removal of uranium from aqueous solution
Graphene (rGO) hydrogel: A promising material for facile removal of uranium from aqueous solution
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石墨烯（rGO）水凝胶：一种有前途的材料，可轻松从水溶液中去除铀
DOI：
10.1016/j.cej.2018.01.037
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发表时间：
2018-04-15
影响因子：
15.1
通讯作者：
Chen, Hong-Bing
中科院分区：
文献类型：
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作者：
He, Yan-Rong;Li, Shi-Cheng;Chen, Hong-Bing
本研究采用抗坏血酸还原氧化石墨烯（GO）制备石墨烯（rGO）水凝胶，以去除水溶液中的U（VI）。制备的还原氧化石墨烯水凝胶具有三维多孔网络结构和良好的机械稳定性。通过批量实验考察了接触时间、pH、初始浓度对吸附U（VI）的影响以及材料的可重复使用性。结果表明，还原氧化石墨烯水凝胶对U（VI）的吸附符合准二级动力学模型，为化学吸附。根据相关系数，Freundlich模型是最适合描述还原氧化石墨烯水凝胶吸附U（VI）过程的等温模型，其最大吸附量为134.23 mg/g （pH 4.0）。溶液pH对U（VI）的吸附有显著影响：从pH 2.0到4.6，吸附量急剧上升，在4.6 ~ 6.5时达到平台期，在pH高于6.5时略有下降。还原氧化石墨烯水凝胶具有良好的可重复使用性，经过10次吸附/解吸循环后，还原氧化石墨烯水凝胶的吸附能力仍保持在94.76%，表明还原氧化石墨烯水凝胶是一种很有前途的去除水溶液中U（VI）的吸附剂，为U（VI）吸附剂的开发提供了新的思路。
In the present study, graphene (rGO) hydrogel was fabricated by reducing graphene oxide (GO) with ascorbic acid to remove U(VI) from aqueous solution. The resulting rGO hydrogel shows a 3D porous network structure and good mechanical stability. The effect of contact time, pH, and initial U(VI) concentration on U(VI) adsorption, as well as the reusability of the material were estimated with batch experiments. The results illustrate that U(VI) adsorption on rGO hydrogel agreed well with pseudo-second order kinetic model, indicating a chemical adsorption. According to correlation coefficients, Freundlich model is the most suitable isothermal model to describe the U(VI) adsorption process of rGO hydrogel, with a maximum adsorption capacity of 134.23 mg/g (pH 4.0). The solution pH posed significant influence on U(VI) adsorption: the adsorption amount rises sharply from pH 2.0 to 4.6, reaches a plateau at 4.6-6.5, and then declines slightly at pH levels above 6.5. The rGO hydrogel shows good reusability, with maintaining 94.76% adsorption ability after ten adsorption/desorption cycles, demonstrating that rGO hydrogel is a promising adsorbent for U(VI) removal from aqueous solution, providing a new insight for the developing of U(VI) adsorbents.