Chen Zhaochuan, Luo Yuting, Li Qiang, Chen Xuemei
MIIT Key Laboratory of Thermal Control of Electronic Equipment, School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, P. R. China.
ACS Appl Mater Interfaces. 2021 Sep 1;13(34):40531-40542. doi: 10.1021/acsami.1c09155. Epub 2021 Aug 19.
Desalination of seawater through solar-driven interfacial evaporation is an efficient approach to solve the freshwater resource shortage problem. However, the salt formation and crystallization during interfacial evaporation limit the long-term stability of the solar evaporator. To further improve the salt-rejecting capability of the solar evaporator, we developed a porous framework photothermal microgroove-structured aerogel (PDA/PEI/PPy@PI-MS MGA, pppMGA) through a combined freeze drying, laser engraving, and chemical polymerization technique. A multilevel water transport network consisting of a three-dimensional (3D) skeleton, a microgroove-structured water channel, and a cotton core is constructed, which can effectively improve the salt-rejecting capability of the aerogel. At the same time, the combination of the 3D porous microgroove structure of the pppMGA evaporative interface and the efficient light absorption capacity of PPy effectively increases the vapor-liquid evaporation area and the light absorption rate (98%). A high evaporation rate (∼1.38 kg m h) and high photothermal conversion efficiency (∼93.04%) can be achieved on the pppMGA evaporator under 1 sun illumination, which can operate stably in high salt concentration (20%) water for 8 h. Even under 3 sun illumination and a 20 wt % NaCl solution, the pppMGA evaporator can operate stably without salt crystallization. Such a photothermal aerogel with high salt-rejecting performance provides a new avenue for designing an interfacial evaporation system that can operate stably under high salt concentration conditions.
通过太阳能驱动界面蒸发进行海水淡化是解决淡水资源短缺问题的一种有效方法。然而，界面蒸发过程中的盐分形成和结晶限制了太阳能蒸发器的长期稳定性。为了进一步提高太阳能蒸发器的排盐能力，我们通过冷冻干燥、激光雕刻和化学聚合技术相结合的方法，开发了一种多孔框架光热微槽结构气凝胶（PDA/PEI/PPy@PI-MS MGA，pppMGA）。构建了一个由三维（3D）骨架、微槽结构水通道和棉芯组成的多级水传输网络，该网络可以有效提高气凝胶的排盐能力。同时，pppMGA蒸发界面的3D多孔微槽结构与PPy的高效光吸收能力相结合，有效增加了气液蒸发面积和光吸收率（98%）。在1个太阳光照下，pppMGA蒸发器可实现高蒸发速率（约1.38 kg m⁻² h⁻¹）和高光热转换效率（约93.04%），并且能够在高盐浓度（20%）的水中稳定运行8小时。即使在3个太阳光照和20 wt% NaCl溶液条件下，pppMGA蒸发器也能稳定运行而不发生盐结晶。这种具有高排盐性能的光热气凝胶为设计一种能够在高盐浓度条件下稳定运行的界面蒸发系统提供了一条新途径。
