Gan Lihong, Zhang Jin, Wu Yangtao, Chen Zhuo, Zhao Zhenyu, Lin Shihong, Jiang Yi
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China.
Department of Civil and Environmental Engineering and Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States.
Environ Sci Technol. 2025 Jan 14;59(1):913-923. doi: 10.1021/acs.est.4c08638. Epub 2024 Dec 30.
Polyelectrolyte multilayer (PEM) membranes, with advantageous features of versatile chemistry and structures, are driving the development of advanced nanofiltration (NF) membranes with exceptional performance. While developing a printing method holds great promise for the eventual mass production of these membranes, reports on the printing method and the underlying mechanisms of membrane formation are currently scarce. Herein, we develop an aerosol-assisted printing (AAP) system for fabricating PEM NF membranes with highly tunable separation characteristics. Our study unveils the three stages of membrane formation from assembly of polyethylenimine (PEI) and poly(sodium 4-styrenesulfonate) (PSS): aerosol deposition, single PE layer formation, and PEM assembly. The droplet deposition is governed by inertial impaction, and the deposited PEs migrate/entangle to form a single PE layer. The thicknesses of the PE layer and PEM exhibit linear growth as the number of printing scan increases. Furthermore, PE interdigitation forms an effective polymeric network barrier, which increases the resistance to solute and water transport. By manipulating the PE deposition mass and layering, PEM membranes with tunable pore radii (0.40-0.56 nm) and water permeability (5-60 L·m·h·bar) were obtained for various water treatment applications, ranging from micropollutant removal to humic acid filtration. Our study offers valuable mechanistic insights into the PEM formation and precise structural adjustment via printing, thus facilitating scalable manufacturing and widespread applications of the PEM NF membranes.
聚电解质多层（PEM）膜具有化学性质和结构多样的优势特性，正推动着具有卓越性能的先进纳滤（NF）膜的发展。虽然开发一种印刷方法对于这些膜的最终大规模生产具有巨大潜力，但目前关于印刷方法以及膜形成的潜在机制的报道却很少。在此，我们开发了一种气溶胶辅助印刷（AAP）系统，用于制造具有高度可调分离特性的PEM NF膜。我们的研究揭示了由聚乙烯亚胺（PEI）和聚（4-苯乙烯磺酸钠）（PSS）组装形成膜的三个阶段：气溶胶沉积、单个PE层形成和PEM组装。液滴沉积受惯性碰撞控制，沉积的PEs迁移/缠结形成单个PE层。随着印刷扫描次数的增加，PE层和PEM的厚度呈线性增长。此外，PE相互交错形成了有效的聚合物网络屏障，增加了对溶质和水传输的阻力。通过控制PE沉积量和层数，获得了具有可调孔径（0.40 - 0.56 nm）和水渗透性（5 - 60 L·m·h·bar）的PEM膜，可用于从微污染物去除到腐殖酸过滤等各种水处理应用。我们的研究为PEM的形成以及通过印刷进行精确结构调整提供了有价值的机理见解，从而促进了PEM NF膜的可扩展制造和广泛应用。
