Zhuang Pengyu, Li Duo, Xu Ning, Yu Xiaoqiang, Zhou Lin
National Laboratory of Solid State Microstructures College of Engineering and Applied Sciences School of Physics Key Laboratory of Intelligent Optical Sensing and Integration Ministry of Education Nanjing University Nanjing 210093 P. R. China.
School of Physics Southeast University Nanjing 211189 P. R. China.
Glob Chall. 2020 Sep 28;5(1):2000053. doi: 10.1002/gch2.202000053. eCollection 2021 Jan.
Highly efficient vapor generation with considerable stability under natural solar irradiance is a promising technology for seawater desalination and wastewater purification. Here a broadband solar absorber of reduced graphene oxide hydrogel membrane (rGOHM), synthesized via an environmentally friendly one-step hydrothermal reduction process, is demonstrated, which shows a high rate of solar vapor production and superior stability. The porous rGOHM containing more than 99.5% water within its small volume floats on the surface of water, exhibiting efficient solar absorption of 98% across 300-2500 nm, as well as sufficient water-pumping pathways. The evaporation rate can be tuned by changing the water volume. By controlling the water volume, the self-floating rGOHM can enable efficient interfacial solar vapor generation at a high rate of 2.33 kg m h under 1 sun, which is comparable to the rate generated by the evaporator with an extra insulator. In addition, the evaporation rate of rGOHM is only slightly affected at a high saltwater concentration (at least 15 wt%), and the rGOHM shows mechanical and physical stability. The superior evaporation performance combined with efficient eradication of wastewater contaminants, cost-effectiveness, and straightforward fabrication process, makes this rGOHMs ideal for advanced high-concentration seawater desalination and wastewater treatment technologies.
在自然太阳辐照下实现高效且具有相当稳定性的蒸汽生成，是一种用于海水淡化和废水净化的很有前景的技术。在此展示了一种通过环境友好的一步水热还原法合成的还原氧化石墨烯水凝胶膜（rGOHM）宽带太阳能吸收器，它具有高太阳能蒸汽产生速率和卓越的稳定性。体积小但含水量超过99.5%的多孔rGOHM漂浮在水面上，在300 - 2500 nm范围内展现出98%的高效太阳能吸收，以及充足的抽水通道。蒸发速率可通过改变水量来调节。通过控制水量，自漂浮的rGOHM在1个太阳光照强度下能够以2.33 kg m² h⁻¹的高速率实现高效界面太阳能蒸汽生成，这与带有额外隔热层的蒸发器所产生的速率相当。此外，在高盐水浓度（至少15 wt%）下，rGOHM的蒸发速率仅受到轻微影响，并且rGOHM表现出机械和物理稳定性。其卓越的蒸发性能，再加上对废水中污染物的高效去除、成本效益以及简单的制造工艺，使得这种rGOHM成为先进的高浓度海水淡化和废水处理技术的理想选择。
