A solar energy recuperator collects and cleans the water from the air

Access to safe water remains one of the greatest challenges for humankind. An advance engineers at the University of Texas at Austin could offer a new solution with solar energy technology that absorbs moisture from the air and returns it as clean water and usable.

The breakthrough, described in a recent issue of the newspaper Advanced Materials, could be used in disaster, water crisis or poverty and developing country situations. The technology relies on hydrogels, gel-polymer hybrid materials designed to be "super sponges" capable of holding large amounts of water.

A research team led by Guihua Yu at the University of Texas' Cockrell University in Austin combined highly absorbent hydrogels that can release water during heating. This unique combination has proven effective in wet and dry weather and is essential for the production of clean and safe drinking water.

With approximately 50,000 cubic kilometers of water contained in the atmosphere, this new system could tap into these reserves and potentially lead to small, inexpensive and portable filtration systems.

"We have developed a completely passive system where all you have to do is let the hydrogel out and get the water back," said Fei Zhao, a postdoctoral researcher at the University of Ottawa. Yu's team and co-author of the study. "The collected water will remain stored in the hydrogel until you expose it to the sun.After about five minutes of natural light, the water is released."

This technology builds on a 2018 breakthrough by Yu and Zhao, who have developed a solar water purification innovation using hydrogels that clean the water. from any source using only solar energy. The new innovation of the team goes even further in this work using water already present in the atmosphere. For both hydrogel-based technologies, Yu and her research team have developed a way to combine materials with both hygroscopic (water-absorbing) qualities and a hydrophilic-reactive hydrophilicity (the ability to release water by simple heating).

"The new material is designed to recover moisture from the air and produce clean water under the sun, avoiding intensive energy consumption," said Yu, an associate professor of materials science. and mechanical engineering.

Harvesting water from the humidity is not really a new concept. Most refrigerators keep things cool through a steam condensation process. However, the common fridge requires a lot of energy to perform this action. UT team technology requires only solar energy, it is compact and can still produce enough water to meet the daily needs of an average household. Prototype tests showed daily water production of up to 50 liters per kilogram of hydrogel.

As an innovative strategy to improve atmospheric water recovery techniques used today, this technology could also replace essential components of solar water purification systems or other moisture-absorbing technologies.

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More information:
Fei Zhao et al. Super absorbent moisture gels for the recovery of atmospheric water any time, Advanced Materials (2019). DOI: 10.1002 / adma.201806446