Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA.
Department of Mechanical and Aerospace Engineering, Rutgers University, Piscataway, NJ, 08854, USA.
Small. 2019 Dec;15(49):e1904590. doi: 10.1002/smll.201904590. Epub 2019 Oct 10.
2D layered nanomaterials have attracted considerable attention for their potential for highly efficient separations, among other applications. Here, a 2D lamellar membrane synthesized using hexagonal boron nitride nanoflakes (h-BNF) for highly efficient ion separation is reported. The ion-rejection performance and the water permeance of the membrane as a function of the ionic radius, ion valance, and solution pH are investigated. The nonfunctionalized h-BNF membranes show excellent ion rejection for small sized salt ions as well as for anionic dyes (>97%) while maintaining a high water permeability, ≈1.0 × 10 L m m h bar ). Experiments show that the ion-rejection performance of the membrane can be tuned by changing the solution pH. The results also suggest that the rejection is influenced by the ionic size and the electrostatic repulsion between fixed negative charges on the BN surface and the mobile ions, and is consistent with the Donnan equilibrium model. These simple-to-fabricate h-BNF membranes show a unique combination of excellent ion selectivity and high permeability compared to other 2D membranes.
二维层状纳米材料因其在高效分离等应用方面的潜力而引起了相当大的关注。在这里，我们报道了一种使用六方氮化硼纳米片（h-BNF）合成的 2D 层状膜，用于高效的离子分离。研究了膜的离子排斥性能和水透过率随离子半径、离子价和溶液 pH 的变化。非功能化的 h-BNF 膜对小尺寸盐离子以及阴离子染料（>97%）表现出优异的离子排斥性能，同时保持高水透过率，≈1.0×10-6 L m-1 h-1 bar-1）。实验表明，通过改变溶液 pH 值可以调节膜的离子排斥性能。结果还表明，排斥作用受离子尺寸和 BN 表面固定负电荷与移动离子之间的静电排斥影响，与唐南平衡模型一致。与其他二维膜相比，这些易于制造的 h-BNF 膜表现出优异的离子选择性和高透过率的独特组合。
