Thin film composite (TFC) polyamide membranes have been widely applied for environmental applications, such as desalination and water reuse. The separation performance of TFC polyamide membranes strongly depends on their nanovoid-containing roughness morphology. These nanovoids not only influence the effective filtration area of the polyamide film but also regulate the water transport pathways through the film. Although there have been ongoing debates on the formation mechanisms of nanovoids, a nanofoaming theory─stipulating the shaping of polyamide roughness morphology by nanobubbles of degassed CO₂ and the vapor of volatile solvents─has gained much attention in recent years. In this review, we provide a comprehensive summary of the nanofoaming mechanism, including related fundamental principles and strategies to tailor nanovoid formation for improved membrane separation performance. The effects of nanovoids on the fouling behaviors of TFC membranes are also discussed. In addition, numerical models on the role of nanovoids in regulating the water transport pathways toward improved water permeance and antifouling ability are highlighted. The comprehensive summary on the nanofoaming mechanism in this review provides insightful guidelines for the future design and optimization of TFC polyamide membranes toward various environmental applications.

中文翻译：

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纳米发泡聚酰胺膜：机理、发展和环境影响


薄膜复合 （TFC） 聚酰胺膜已广泛用于环境应用，例如海水淡化和水回用。TFC 聚酰胺膜的分离性能在很大程度上取决于其含纳米空隙的粗糙度形态。这些纳米空隙不仅影响聚酰胺薄膜的有效过滤面积，还调节通过薄膜的水传输途径。尽管关于纳米空隙的形成机制的争论一直存在，但纳米发泡理论——规定了脱气 CO₂ 的纳米气泡和挥发性溶剂的蒸汽对聚酰胺粗糙度形态的塑造——近年来引起了广泛关注。在这篇综述中，我们提供了纳米发泡机制的全面总结，包括相关的基本原理和策略，以定制纳米空隙形成以提高膜分离性能。还讨论了纳米孔对 TFC 膜污染行为的影响。此外，还强调了纳米空隙在调节水传输途径以提高透水和防污能力方面的作用的数值模型。本文对纳米发泡机理的全面总结为未来针对各种环境应用的 TFC 聚酰胺膜的设计和优化提供了有见地的指导。