Wang Hongjian, Zhao Jiashuai, Li Yang, Cao Yu, Zhu Ziting, Wang Meidi, Zhang Runnan, Pan Fusheng, Jiang Zhongyi
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.
Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, 300192, People's Republic of China.
Nanomicro Lett. 2022 Nov 9;14(1):216. doi: 10.1007/s40820-022-00968-5.
Aqueous two-phase system features with ultralow interfacial tension and thick interfacial region, affording unique confined space for membrane assembly. Here, for the first time, an aqueous two-phase interfacial assembly method is proposed to fabricate covalent organic framework (COF) membranes. The aqueous solution containing polyethylene glycol and dextran undergoes segregated phase separation into two water-rich phases. By respectively distributing aldehyde and amine monomers into two aqueous phases, a series of COF membranes are fabricated at water-water interface. The resultant membranes exhibit high NaCl rejection of 93.0-93.6% and water permeance reaching 1.7-3.7 L m h bar, superior to most water desalination membranes. Interestingly, the interfacial tension is found to have pronounced effect on membrane structures. The appropriate interfacial tension range (0.1-1.0 mN m) leads to the tight and intact COF membranes. Furthermore, the method is extended to the fabrication of other COF and metal-organic polymer membranes. This work is the first exploitation of fabricating membranes in all-aqueous system, confering a green and generic method for advanced membrane manufacturing.
双水相体系具有超低界面张力和较厚的界面区域，为膜组装提供了独特的受限空间。在此，首次提出了一种双水相界面组装方法来制备共价有机框架（COF）膜。含有聚乙二醇和葡聚糖的水溶液发生分离相分离，形成两个富水相。通过将醛和胺单体分别分布到两个水相中，在水 - 水界面处制备了一系列COF膜。所得膜对NaCl的截留率高达93.0 - 93.6%，水通量达到1.7 - 3.7 L m⁻² h⁻¹ bar⁻¹，优于大多数海水淡化膜。有趣的是，发现界面张力对膜结构有显著影响。合适的界面张力范围（0.1 - 1.0 mN m⁻¹）会导致COF膜致密且完整。此外，该方法还扩展到了其他COF膜和金属有机聚合物膜的制备。这项工作首次探索了在全水体系中制备膜，为先进膜制造提供了一种绿色且通用的方法。
