Thin-film nanocomposite (TFN) membranes have been increasingly used in seawater desalination and wastewater reclamation. Despite their potential to overcome the long-standing permeability–selectivity trade-off, the underlying mechanisms for the transport of water through TFN membranes are not fully understood. In this study, we conducted an in-depth analysis of the transport of water through the TFN membranes containing nanoparticles with systematically changed properties (hydrophilic vs hydrophobic and porous vs nonporous). For the first time, we were able to resolve the respective contributions to the enhanced membrane performance by the exterior and interior channels of the nanofillers based on direct experimental evidence. Incorporating solid hydrophobic nanofillers showed little enhancement of water flux. In contrast, exterior channels created by hydrophilic nanofillers and interior channels of porous nanofillers had water flux enhancements of 26.9% and 18.3%, respectively, under similar particle loading conditions. Furthermore, the combined effects of both exterior and interior channels resulted in a 51.9% flux enhancement. Our work provides mechanistic insights into the formation and transport mechanisms involved in TFN membranes, which lay a solid foundation for optimizing these membranes for desalination and water reuse.

中文翻译：

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探究纳米填料的内部和外部通道对薄膜纳米复合反渗透膜增强分离性能的贡献

薄膜纳米复合材料（TFN）膜已越来越多地用于海水淡化和废水回收中。尽管它们有潜力克服长期存在的渗透性-选择性之间的折衷，但是通过TFN膜传输水的基本机制尚未得到充分了解。在这项研究中，我们对TFN膜中水的传输进行了深入分析，该TFN膜包含纳米粒子，这些纳米粒子具有系统地改变的特性（亲水性，疏水性和多孔性与无孔性）。首次，我们能够基于直接的实验证据，通过纳米填料的外部和内部通道来解决各自对增强膜性能的贡献。掺入固体疏水性纳米填料显示出很少的水通量增强。相反，在相似的颗粒负载条件下，由亲水性纳米填料产生的外部通道和多孔纳米填料的内部通道的水通量分别提高了26.9％和18.3％。此外，外部和内部通道的综合作用导致通量提高了51.9％。我们的工作为TFN膜的形成和运输机理提供了机械方面的见解，为优化这些膜的脱盐和水再利用奠定了坚实的基础。