Nanofiltration (NF) membranes have been widely applied in many important environmental applications, including water softening, surface/groundwater purification, wastewater treatment, and water reuse. In recent years, a new class of piperazine (PIP)-based NF membranes featuring a crumpled polyamide layer has received considerable attention because of their great potential for achieving dramatic improvements in membrane separation performance. Since the report of novel crumpled Turing structures that exhibited an order of magnitude enhancement in water permeance ( Science 2018, 360 (6388), 518−521), the number of published research papers on this emerging topic has grown exponentially to approximately 200. In this critical review, we provide a systematic framework to classify the crumpled NF morphologies. The fundamental mechanisms and fabrication methods involved in the formation of these crumpled morphologies are summarized. We then discuss the transport of water and solutes in crumpled NF membranes and how these transport phenomena could simultaneously improve membrane water permeance, selectivity, and antifouling performance. The environmental applications of these emerging NF membranes are highlighted, and future research opportunities/needs are identified. The fundamental insights in this review provide critical guidance on the further development of high-performance NF membranes tailored for a wide range of environmental applications.

中文翻译：

---

具有皱褶聚酰胺薄膜的纳滤膜：对机理、性能和环境应用的批判性评论

纳滤 (NF) 膜已广泛应用于许多重要的环境应用，包括水软化、地表水/地下水净化、废水处理和中水回用。近年来，一类具有皱褶聚酰胺层的新型哌嗪（PIP）基纳滤膜因其在显着提高膜分离性能方面的巨大潜力而​​受到了广泛关注。自从报告了新型皱褶图灵结构的水渗透性提高了一个数量级（Science 2018 , 360(6388), 518−521)，关于这一新兴主题的已发表研究论文数量呈指数增长至大约 200 篇。在这篇批判性评论中，我们提供了一个系统框架来对皱巴巴的 NF 形态进行分类。总结了这些皱褶形态形成所涉及的基本机制和制造方法。然后，我们讨论了皱巴巴的 NF 膜中水和溶质的迁移，以及这些迁移现象如何同时提高膜的透水性、选择性和防污性能。重点介绍了这些新兴 NF 膜的环境应用，并确定了未来的研究机会/需求。