Wang Shuai, Gui Lishuang, Qiao Di, Tao Meiling, Huang Shilin, Tian Xuelin
State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China.
Key Laboratory for Polymeric Composite & Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, 510006, China.
Angew Chem Int Ed Engl. 2025 Jul;64(29):e202507913. doi: 10.1002/anie.202507913. Epub 2025 May 22.
Membrane distillation (MD) is a promising separation technique for producing pure water from brine using low-grade heat. Covalent organic framework (COF) membranes with high porosity and well-ordered pore structure exhibit excellent flux and salt rejection during MD. However, long-term MD operation is often restricted by the inevitable gradual wetting of COF membranes, which causes deterioration of salt rejection, primarily resulting from the lack of intrinsic hydrophobicity. Herein, a fluorinated COF (TGTf) membrane with intrinsic hydrophobicity and excellent anti-wetting property is reported. Under 65 °C and 12 kPa operation pressure, the TGTf membrane maintained a high water flux of 195 L m h and a salt rejection of 99.80% over 168 h of MD operation, which is the longest operation time ever reported for MD using COF membranes. In addition, the TGTf membrane showed unparalleled resistance to scaling and organic fouling, demonstrating great potential for real-world brine treatment. Experimental and simulation studies revealed that incorporation of fluorine atom not only enhanced the hydrophobicity of the COF membrane, but also created electrostatic barriers within the fluorinated nanochannels, efficiently preventing ion penetration. These results underscore the remarkable potential of fluorinated COF membranes in MD, offering a promising solution for sustainable brine desalination.
膜蒸馏（MD）是一种很有前景的分离技术，可利用低品位热量从盐水中生产纯水。具有高孔隙率和有序孔结构的共价有机框架（COF）膜在膜蒸馏过程中表现出优异的通量和脱盐率。然而，长期的膜蒸馏操作常常受到COF膜不可避免的逐渐润湿的限制，这会导致脱盐率下降，主要原因是缺乏内在疏水性。在此，报道了一种具有内在疏水性和优异抗润湿性能的氟化COF（TGTf）膜。在65℃和12kPa的操作压力下，TGTf膜在168小时的膜蒸馏操作中保持了195L·m⁻²·h⁻¹的高水通量和99.80%的脱盐率，这是使用COF膜进行膜蒸馏报道的最长操作时间。此外，TGTf膜对结垢和有机污染表现出无与伦比的抗性，显示出在实际盐水处理中的巨大潜力。实验和模拟研究表明，氟原子的引入不仅增强了COF膜的疏水性，还在氟化纳米通道内形成了静电屏障，有效地阻止了离子渗透。这些结果强调了氟化COF膜在膜蒸馏中的巨大潜力，为可持续盐水淡化提供了一个有前景的解决方案。
