Layered graphene oxide membranes functioned by amino acids for efficient separation of metal ions
Layered graphene oxide membranes functioned by amino acids for efficient separation of metal ions
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DOI：
10.1016/j.apsusc.2021.149145
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发表时间：
2021-04
影响因子：
6.7
通讯作者：
Bo Zheng;Xianxian Chu;Han Li;Wu Xiuli;Xin Zhao;Yi-mei Tian
中科院分区：
文献类型：
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作者：
Bo Zheng;Xianxian Chu;Han Li;Wu Xiuli;Xin Zhao;Yi-mei Tian
铅离子(Pb2+)作为一种重金属，对人类健康和生态环境构成极大威胁。石墨烯及其衍生物具有优异的性能，有望用于净水。通过脱水缩合的方法设计了氧化石墨烯膜的氨基酸官能团。用分子动力学方法研究了氨基酸基团对膜分离金属离子性能的影响。在透水性基本相同的前提下，末端带负电荷的丙氨酸基团对Pb2+的截留率是羧基的1.6倍。数密度图和径向分布函数表明，在带负电荷的丙氨酸基团周围会形成一大片Pb2+的局部高密度区域。同时，负基团的静电吸引可以有效地降低Pb2+和Na+的扩散系数。结果表明，在带负电荷的丙氨酸作用下，层状氧化石墨烯膜对金属离子的截留率显著提高，但对水的透过率损失不大。
As a kind of heavy metal, lead ions (Pb2+) are a great threat to human health and the ecological environment. Due to their excellent properties, graphene and its derivatives are expected to be used for water purification. Amino acid functional groups were designed for graphene oxide membranes via dehydration condensation. The effects of the amino acid groups on the membrane performance for separating metal ions were investigated by the molecular dynamics. Under the premise that the water permeability is basically the same, the retention rate for Pb2+by alanine groups with negatively charged terminals is 1.6 times of that by the carboxyl groups. The number-density map and the radial distribution function indicate that a large area of local high-density regions of Pb2+will be formed around the negatively charged alanine groups. At the same time, the diffusion coefficient for Pb2+and Na+can be effectively reduced by the electrostatic attraction of the negative groups. It is concluded that functioned by the negatively charged alanine, the retention rate for metal ions by the layered graphene oxide membranes can be significantly improved at the cost of a little loss in water permeability.