Recent developments in nanomaterials have greatly advanced the design and fabrication of water filtration membranes and hopefully alleviate the deteriorating freshwater scarcity. In this work, we demonstrated that lamellar stacking of layered black phosphorus (BP) can serve as an efficient membrane for seawater desalination. Using molecular dynamics simulations, we show that the nano-channels inside BP membranes can effectively block ionic passage while maintaining high water flux (~ 30 L/cm²/day/MPa) at a large range of interlayer spacing (9 Å to 12 Å). Despite the in-plane anisotropy of the BP membrane, the filtration performance of the nano-channels is barely affected by the orientation of the adjacent BP layers. Quantitative potential of mean force analysis indicates that the excellent water filtration performance is attributed to the high energy barriers (>15 kJ/mol) for ions versus the low energy barrier (~ 2 kJ/mol) for water to enter the nano-channels. Moreover, the effect of defects presented in the BP membrane to water filtration has been addressed which is found to hardly affect the filtration performance, indicating the robustness of the BP-based nano-channels. Therefore, the results presented in this study offer a competitive membrane for seawater desalination which is also expected to guide the future design of membrane materials.

纳米材料的最新发展极大地推进了水过滤膜的设计和制造，并有望减轻日益恶化的淡水短缺。在这项工作中，我们证明了层状黑磷（BP）的层状堆积可以用作海水淡化的有效膜。使用分子动力学模拟，我们表明BP膜内部的纳米通道可以有效地阻止离子通过，同时保持高水通量（〜30 L / cm ²/ day / MPa）在较大的层间距（9到12Å）范围内。尽管BP膜具有面内各向异性，但相邻BP层的取向几乎不会影响纳米通道的过滤性能。平均力分析的定量潜力表明，出色的水过滤性能归因于离子进入离子通道的高能垒（> 15 kJ / mol）与水进入纳米通道的低能垒（〜2 kJ / mol）。而且，已经解决了BP膜中存在的缺陷对水过滤的影响，发现该缺陷几乎不影响过滤性能，表明基于BP的纳米通道的坚固性。因此，