Institut Européen des Membranes, IEM, UMR 5635, Université Montpellier, ENSCM, CNRS, Montpellier, France.
Laboratoire Charles Coulomb, L2C, Université de Montpellier, CNRS, Montpellier, France.
Nat Mater. 2019 Oct;18(10):1112-1117. doi: 10.1038/s41563-019-0464-7. Epub 2019 Aug 26.
Nanolaminate membranes made of two-dimensional materials such as graphene oxide are promising candidates for molecular sieving via size-limited diffusion in the two-dimensional capillaries, but high hydrophilicity makes these membranes unstable in water. Here, we report a nanolaminate membrane based on covalently functionalized molybdenum disulfide (MoS) nanosheets. The functionalized MoS membranes demonstrate >90% and ~87% rejection for micropollutants and NaCl, respectively, when operating under reverse osmotic conditions. The sieving performance and water flux of the functionalized MoS membranes are attributed both to control of the capillary widths of the nanolaminates and to control of the surface chemistry of the nanosheets. We identify small hydrophobic functional groups, such as the methyl group, as the most promising for water purification. Methyl- functionalized nanosheets show high water permeation rates as confirmed by our molecular dynamic simulations, while maintaining high NaCl rejection. Control of the surface chemistry and the interlayer spacing therefore offers opportunities to tune the selectivity of the membranes while enhancing their stability.
由氧化石墨烯等二维材料制成的纳米层膜是通过二维毛细管中尺寸限制扩散进行分子筛分的有前途的候选材料，但高亲水性使这些膜在水中不稳定。在这里，我们报告了一种基于共价功能化二硫化钼 (MoS) 纳米片的纳米层膜。在反渗透条件下运行时，功能化 MoS 膜对微污染物和 NaCl 的截留率分别>90%和~87%。功能化 MoS 膜的筛分性能和水通量归因于对纳米层的毛细管束宽度的控制和纳米片表面化学的控制。我们确定了小的疏水性官能团，如甲基，作为最有前途的水净化官能团。我们的分子动力学模拟证实，甲基功能化纳米片具有高水透过率，同时保持高 NaCl 截留率。因此，控制表面化学和层间间距为调节膜的选择性同时提高其稳定性提供了机会。
