Researchers from Shanghai Jiao Tong University in China have developed a new solar-powered atmospheric water harvesting technology that could help provide enough drinking water for people to survive in dryland areas in water-stressed countries.

The United Nations estimates that 3.5 million die every year from water-related diseases and the areas most in need of improved drinking water are also located in some of the sunniest places in the world.

Multiple uses

“This atmospheric water harvesting technology can be used to increase the daily water supply needs, as household drinking water, industrial water, and water for personal hygiene,” said author Ruzhu Wang.

The researchers synthesized a super-hygroscopic gel using plant derivatives and hygroscopic salts that were capable of absorbing and retaining an unparalleled amount of water. One kilogram of dry gel could adsorb 1.18 kilograms of water in arid atmospheric environments and up to 6.4 kilograms in humid atmospheric environments, they estimate. This hygroscopic gel was simple and inexpensive to prepare and would consequently be suitable for large-scale preparation.

In addition to daily water production, these sorbent materials that harvest atmosphere water could also play an important role in future applications such as dehumidification, agriculture irrigation, and thermal management for electronic devices, according to the researchers.

In an outdoor prototype demonstration, the team found it released adsorbed water even in the morning or afternoon when the sun is weak. The system could also achieve simultaneous adsorption and desorption during the daytime.

The team now plans to work to achieve simultaneous adsorption and desorption, using renewable energy to maximize daily water yield per unit mass of adsorbent.

Citation: Chengjie Xiang, Xinge Yang, Fangfang Deng, Zhihui Chen, and Ruzhu Wang, Dec. 5, 2023, Applied Physics Reviews, https://doi.org/10.1063/5.0160682 (open-access)

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