Developing thin-film composite (TFC) nanofiltration (NF) membranes with high water permeability and salt rejection is highly desirable in water desalination. In this study, a new TFC membrane with high NF performances was developed to achieve such a goal by constructing active separation layer with a special crater-like surface morphology using a rigidly-contorted spirocyclic monomer, 5,5,6′,6′-tetrahydroxy-3,3,3′,3′-tetramethyl spirobisindane (TTSBI), as the co-monomer with piperazine (PIP) in aqueous phase during interfacial polymerization (IP) process. This design endowed the separation layer with the characteristics of low thickness, high microporosity, and high permeation surface area. The pure water permeability was therefore increased to 9.9 L m⁻² h ⁻¹ bar⁻¹, approximately two times higher than that of the typical TFC NF membrane prepared with PIP and trimesoyl chloride, without compromise in the rejection (the rejection of Na₂SO₄ up to 98%). The introduction of TTSBI tuned the diffusion and reaction behaviors of monomers at the aqueous-organic interface and controlled the special microporous structure and surface morphology, which are advantageous to the improvement of water permeability. This study provides new insights for synthesizing highly permeable TFC NF membranes with remarkable rejection characteristics to address the crisis of the current potable water scarcity.

在水脱盐中，非常需要开发具有高透水性和脱盐率的薄膜复合（TFC）纳滤（NF）膜。在这项研究中，开发了一种新型的具有高NF性能的TFC膜，以通过使用刚性扭曲的螺环单体5,5,6'，6'-四羟基-3,3,3'，3'-四甲基spirobisindane（TTSBI），作为共与哌嗪（PIP）在水相中时界面聚合（IP）过程-单体。该设计赋予分离层低厚度，高微孔率和高渗透表面积的特征。因此，纯净水的渗透性增加到9.9 L m ^-2  h ^-1 bar ^-1，比使用PIP和均苯三甲酰氯制得的典型TFC NF膜高出约两倍，而不会影响截留率（Na ₂ SO ₄截留率高达98％）。TTSBI的引入调节了单体在水-有机界面的扩散和反应行为，并控制了特殊的微孔结构和表面形态，有利于提高水的渗透性。这项研究为合成具有显着排斥特性的高渗透性TFC NF膜提供了新的见解，以解决当前饮用水短缺的危机。