Institute of Condensed Matter Physics, Zhejiang Normal University, Jinhua 321004, China.
Nanoscale. 2014;6(3):1865-70. doi: 10.1039/c3nr04984a.
Permeation through membrane with pores is important in the choice of materials for filtration and separation techniques. Here, we report by the molecular dynamics simulations that a single-layer graphyne membrane can be impermeable to salt ions, while it allows the permeation of water molecules. The salt rejection and water permeability of graphyne are closely related to the hydrostatic pressure, type of graphyne membrane, and the salt concentration of solution, respectively. By analyzing hydration shell structure, we found that the average coordination number of ions plays a key role in water purification. Our calculation showed that the salt rejection of the graphyne-3 membrane is the best and it can keep an ideal rate of 100% in consideration cases. In comprehensive evaluation of both salt rejection and permeability, the graphyne-4 is a perfect purification membrane. To sum up, our results indicated that the graphynes (graphyne-3 and -4) not only have higher salt rejection but also possess higher water permeability which is several orders of magnitude higher than conventional reverse osmosis membranes. The single-layer graphyne membrane may have a great potential application as a membrane for water purification.
具有孔道的膜渗透对于过滤和分离技术的材料选择很重要。在这里，我们通过分子动力学模拟表明，单层石墨炔膜可以对盐离子不可渗透，而允许水分子渗透。石墨炔的盐排斥和水渗透性分别与静水压力、石墨炔膜的类型和溶液的盐浓度密切相关。通过分析水合壳结构，我们发现离子的平均配位数在水净化中起着关键作用。我们的计算表明，石墨炔-3 膜的盐排斥效果最佳，在考虑的情况下可以保持理想的 100%去除率。在盐排斥和渗透性的综合评估中，石墨炔-4 是一种完美的净化膜。总之，我们的结果表明，石墨炔（石墨炔-3 和 -4）不仅具有更高的盐排斥率，而且具有更高的水渗透性，比传统的反渗透膜高几个数量级。单层石墨炔膜作为水净化膜具有很大的应用潜力。
