Abstract Although a highly porous support membrane has attracted increasing attention as an alternative to enhance the water permeability of a thin-film composite (TFC) membrane without compromising salt rejection, its feasibility has not ever been tested in seawater desalination. This study explored the availability and potential of a highly porous microstructured (HPμS) support membrane as a support for a seawater reverse osmosis (SWRO) membrane. Our lab-made membranes, TFC-HPμS, exhibited a higher water permeability of 1.62 L m−2 h−1 bar−1 as compared with most of the state-of-the-art SWRO membranes recently reported in the literature, while achieving comparable NaCl rejection (99%) in SWRO test condition (55 bar, 35,000 mg L−1 of NaCl). This excellent performance is thought to stem from the HPμS support endowing a TFC membrane with comparable mechanical properties to that of existing support used for conventional SWRO membrane and shortened effective diffusion pathway of water molecules over the active layer. The robustness and enhanced mechanical strength of the TFC-HPμS membrane are attributed to its narrow and regularly arranged finger-like structure ensuring the even distribution of local stresses, thereby eliminating the presence of stress convergence points. The shortened effective diffusion pathway was estimated to be achieved mainly by less localized surface pores due to the HPμS support's highly porous surface with a larger number of even distributed surface pores. This study potentially opens up another workable pathway in the fabrication of SWRO membranes with enhanced performance without significant sacrifice of the selectivity.

中文翻译：

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在多孔微结构载体上制备薄膜复合海水反渗透膜的可行性和性能

摘要 尽管高度多孔的支撑膜作为一种在不影响脱盐率的情况下提高薄膜复合 (TFC) 膜的透水性的替代方案已引起越来越多的关注，但其可行性尚未在海水淡化中进行过测试。本研究探讨了高度多孔微结构 (HPμS) 支撑膜作为海水反渗透 (SWRO) 膜支撑的可用性和潜力。与最近文献中报道的大多数最先进的 SWRO 膜相比，我们实验室制造的膜 TFC-HPμS 表现出更高的透水性，为 1.62 L m-2 h-1 bar-1，同时实现了SWRO 测试条件（55 bar，35,000 mg L-1 NaCl）下的 NaCl 排斥（99%）。这种优异的性能被认为源于 HPμS 支撑赋予 TFC 膜与用于传统 SWRO 膜的现有支撑相当的机械性能，并缩短了水分子在活性层上的有效扩散路径。TFC-HPμS 膜的坚固性和增强的机械强度归因于其狭窄且规则排列的指状结构，确保局部应力的均匀分布，从而消除应力收敛点的存在。由于 HPμS 载体的高度多孔表面具有大量均匀分布的表面孔隙，因此估计缩短的有效扩散路径主要是通过较少的局部表面孔隙实现的。