Kuang Yudi, Chen Chaoji, He Shuaiming, Hitz Emily M, Wang Yilin, Gan Wentao, Mi Ruiyu, Hu Liangbing
Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA.
Adv Mater. 2019 Jun;31(23):e1900498. doi: 10.1002/adma.201900498. Epub 2019 Apr 16.
Emerging solar desalination by interfacial evaporation shows great potential in response to global water scarcity because of its high solar-to-vapor efficiency, low environmental impact, and off-grid capability. However, solute accumulation at the heating interface has severely impacted the performance and long-term stability of current solar evaporation systems. Here, a self-regenerating solar evaporator featuring excellent antifouling properties using a rationally designed artificial channel-array in a natural wood substrate is reported. Upon solar evaporation, salt concentration gradients are formed between the millimeter-sized drilled channels (with a low salt concentration) and the microsized natural wood channels (with a high salt concentration) due to their different hydraulic conductivities. The concentration gradients allow spontaneous interchannel salt exchange through the 1-2 µm pits, leading to the dilution of salt in the microsized wood channels. The drilled channels with high hydraulic conductivities thus function as salt-rejection pathways, which can rapidly exchange the salt with the bulk solution, enabling the real-time self-regeneration of the evaporator. Compared to other salt-rejection designs, the solar evaporator exhibits the highest efficiency (≈75%) in a highly concentrated salt solution (20 wt% NaCl) under 1 sun irradiation, as well as long-term stability (over 100 h of continuous operation).
新兴的界面蒸发太阳能海水淡化技术因其高太阳能-蒸汽效率、低环境影响和离网能力，在应对全球水资源短缺方面显示出巨大潜力。然而，加热界面处的溶质积累严重影响了当前太阳能蒸发系统的性能和长期稳定性。在此，报道了一种在天然木材基质中使用合理设计的人工通道阵列的具有优异防污性能的自再生太阳能蒸发器。在太阳能蒸发过程中，由于毫米级钻孔通道（盐浓度低）和微米级天然木材通道（盐浓度高）的水力传导率不同，在它们之间形成了盐浓度梯度。浓度梯度允许盐通过1-2微米的凹坑在通道间自发交换，从而导致微米级木材通道中的盐被稀释。因此，具有高水力传导率的钻孔通道起到了排盐通道的作用，它可以与本体溶液快速交换盐分，实现蒸发器的实时自再生。与其他排盐设计相比，该太阳能蒸发器在1个太阳辐射下的高浓度盐溶液（20 wt% NaCl）中表现出最高效率（约75%）以及长期稳定性（连续运行超过100小时）。
