Li Yin, Chen Kebing, Zhu Liangliang, Li Qing, Chen Su
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering and Jiangsu Key Laboratory of Fine Chemicals and Functional Polymer Materials, Nanjing Tech University, Nanjing 210009, P. R. China.
Nanoscale Horiz. 2025 Jul 21;10(8):1741-1748. doi: 10.1039/d5nh00186b.
Janus nanofiber membrane has emerged as a promising solar-driven interfacial evaporator for seawater desalination. However, salt ion accumulation and crystallization persist during long-term operation, which remains a key challenge. In this work, we report a hydrophilic-hydrophobic Janus nanofiber membrane evaporator, which is prepared continuous microfluidic electrospinning. This method allows chemical reaction of tannin (TA) and Fe to be carried out in a "Y" chip during the spinning process, enabling rapid, facile, and flexible fabrication of the nanofiber membrane. TA is rich in hydroxyl groups, which endows the bottom layer with hydrophilicity and electronegativity, thereby enhancing the water transport and Donnan effect. Thus, a high evaporation rate of 1.73 kg m h in pure water is achieved. More importantly, long-term stability in seawater desalination is realized with an evaporation rate of 1.68 kg m h, and there is no salt crystallization on the surface during continuous evaporation for 8 hours in 10 wt% NaCl solution. On the one hand, the bottom layer shows electronegativity, which is liable to immobilize cations Na and repel anions Cl, achieving the purpose of salt resistance. On the other hand, the Janus structure also favors the redissolution of concentrated salts into raw water, further avoiding salt accumulation. This work offers a promising common strategy for constructing high-performance Janus evaporator, which will stimulate the development of seawater desalination.
Janus纳米纤维膜已成为一种有前景的用于海水淡化的太阳能驱动界面蒸发器。然而，在长期运行过程中盐离子积累和结晶问题仍然存在，这仍是一个关键挑战。在这项工作中，我们报道了一种亲疏水Janus纳米纤维膜蒸发器，它是通过连续微流电纺制备的。这种方法允许单宁酸（TA）和铁在纺丝过程中于“Y”形芯片中发生化学反应，从而能够快速、简便且灵活地制备纳米纤维膜。TA富含羟基，这赋予底层亲水性和电负性，从而增强了水的传输和唐南效应。因此，在纯水中实现了1.73 kg m⁻² h⁻¹的高蒸发速率。更重要的是，在海水淡化中实现了长期稳定性，蒸发速率为1.68 kg m⁻² h⁻¹，并且在10 wt% NaCl溶液中连续蒸发8小时期间表面没有盐结晶。一方面，底层显示电负性，易于固定阳离子Na⁺并排斥阴离子Cl⁻，达到抗盐的目的。另一方面，Janus结构也有利于浓缩盐重新溶解到原水中，进一步避免盐积累。这项工作为构建高性能Janus蒸发器提供了一种有前景的通用策略，这将推动海水淡化的发展。
