Solar steam water purification and fog collection are two independent processes that could enable abundant fresh water generation. We developed a hydrogel membrane that contains hierarchical three-dimensional microstructures with high surface area that combines both functions and serves as an all-day fresh water harvester. At night, the hydrogel membrane efficiently captures fog droplets and directionally transports them to a storage vessel. During the daytime, it acts as an interfacial solar steam generator and achieves a high evaporation rate of 3.64 kg m−2 h−1 under 1 sun enabled by improved thermal/vapor flow management. With a homemade rooftop water harvesting system, this hydrogel membrane can produce fresh water with a daily yield of ~34 L m−2 in an outdoor test, which demonstrates its potential for global water scarcity relief.
Bibliographical noteFunding Information:
We thank Dr. Bruce S. Brunschwig for help with the solar simulator and Daryl Yee for help with 3D printing. We thank Shu Yan for help with drawing schemes. J.R.G. acknowledges the financial support of the Resnick Sustainability Institute and of the Caltech Space Solar Power Project. H.A.A. acknowledges financial support from the Joint Center for Artificial Photosynthesis, a Department of Energy (DOE) Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. O. I. acknowledges support from the Caltech Space Solar Power Project and the 3M foundation.
© 2021, The Author(s).
PubMed: MeSH publication types
- Journal Article
- Research Support, U.S. Gov't, Non-P.H.S.
- Research Support, Non-U.S. Gov't