Loh Ching Yoong, Pang Tianting, Zhang Dengsong, Burrows Andrew D, Xie Ming
Department of Chemical Engineering, University of Bath, Bath BA2 7AY, United Kingdom.
Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444, PR China.
ACS Appl Polym Mater. 2025 Jun 17;7(12):7824-7835. doi: 10.1021/acsapm.5c00491. eCollection 2025 Jun 27.
The increasing demand for sustainable solutions to oil-water separation and end-of-life membrane disposal has prompted the development of recyclable membrane technologies. In this study, we present an innovative approach to fabricating closed-loop, recyclable nanofibrous membranes (RFMs) utilizing reversible covalent networks based on the Diels-Alder reaction. A methacrylate-based copolymer was synthesized via free radical polymerization, combining hydrophobic monomers for enhanced separation performance, with furan-functionalized monomers for recyclability. This copolymer was electrospun into a porous substrate and cross-linked with bismaleimide cross-linkers to form a dynamic covalent network. By incorporating postthermal modification to the nanofibrous membrane, the hydrophobicity and the membrane porosity can be optimized. The resulting RFM exhibited outstanding oil-water separation capabilities, achieving a pure oil flux of up to 1,187 LMH with a separation efficiency up to 99% in water-oil emulsions, as demonstrated in tests with dichloromethane and other oils. Notably, the RFMs maintained structural and chemical stability after two recycling cycles, with recycled membranes retaining fluxes of 474-1,187 LMH and efficiencies of 98.8-99.5%. Thermal and mechanical characterizations confirmed the great stability of the membranes, with the Diels-Alder reaction enabling depolymerization and reformation of the network without causing significant degradation. Additionally, the RFMs were recycled the third time, maintaining the fluxes (752 to 823 LMH) from the previous generation with a slight decrease in separation efficiency in dichloromethane-water emulsion separation (98.3 to 97%). By integrating dynamic covalent chemistry with scalable fabrication methods, RFMs represent a transformative step toward a circular economy in oil-water separation and broader wastewater treatment and resource recovery.
对油水分离和废弃膜处理的可持续解决方案的需求不断增加，促使了可回收膜技术的发展。在本研究中，我们提出了一种创新方法，利用基于狄尔斯-阿尔德反应的可逆共价网络来制造闭环、可回收的纳米纤维膜（RFM）。通过自由基聚合合成了一种基于甲基丙烯酸酯的共聚物，将用于提高分离性能的疏水单体与用于可回收性的呋喃官能化单体结合起来。该共聚物通过静电纺丝制成多孔基材，并与双马来酰亚胺交联剂交联形成动态共价网络。通过对纳米纤维膜进行后热改性，可以优化其疏水性和膜孔隙率。所得的RFM表现出出色的油水分离能力，在水-油乳液测试中，以二氯甲烷和其他油类为例，实现了高达1187 LMH的纯油通量和高达99%的分离效率。值得注意的是，RFM在两个循环周期后保持了结构和化学稳定性，回收后的膜保留了474-1187 LMH的通量和98.8-99.5%的效率。热学和力学表征证实了膜具有很高的稳定性，狄尔斯-阿尔德反应使网络能够解聚和重新形成，而不会导致显著降解。此外，RFM进行了第三次回收，在前一代通量（752至823 LMH）的基础上保持稳定，在二氯甲烷-水乳液分离中的分离效率略有下降（98.3%至97%）。通过将动态共价化学与可扩展的制造方法相结合，RFM代表了在油水分离以及更广泛的废水处理和资源回收方面迈向循环经济的变革性一步。
