Spongy Device Draws Water from Air Using Sunlight for Efficient Harvesting
by Simon Mansfield
Sydney, Australia (SPX) May 12, 2025
Researchers from Australia and China have developed a sponge-like device capable of extracting water from thin air, leveraging solar energy to release the collected moisture. This breakthrough addresses the limitations of existing technologies like fog harvesting and radiative cooling, which often struggle in low-humidity environments.
The water-harvesting device maintains its efficiency across a wide humidity spectrum, ranging from 30% to 90%, and operates effectively in temperatures from 5 to 55 degrees Celsius. It utilizes refined balsa wood with a naturally porous structure, enhanced to absorb atmospheric moisture and release it on demand.
Dr. Derek Hao, a senior researcher at RMIT University’s School of Science, explained that the innovation builds on the natural architecture of balsa wood, integrating lithium chloride, iron oxide nanoparticles, and a carbon nanotube layer to boost its water absorption and release capabilities. “Billions of people around the world lack access to drinkable water, and millions die from water-borne diseases every year,” said Hao.
The research, conducted in collaboration with five Chinese institutions, was led by Dr. Junfeng Hou from Zhejiang A&F University. The team employed artificial intelligence to optimize the device’s performance under varying environmental conditions, ensuring efficient water collection and discharge.
During lab tests, the device absorbed approximately 2 milliliters of water per gram of material at 90% relative humidity and released nearly all of it within 10 hours under sunlight – a notable improvement over many existing methods. In outdoor trials, it captured 2.5 milliliters of water per gram overnight and released most of it during the day, achieving a daily water collection efficiency of 94%. At 30% humidity, it absorbed 0.6 milliliters per gram.
The innovative design allows the material to maintain flexibility and functionality even after 20 days at -20 degrees Celsius, demonstrating exceptional freeze resistance and durability over multiple cycles. The device retained over 88% of its original efficiency after 10 absorption-release cycles.
Hao highlighted the potential applications of the device in emergency scenarios, particularly in disaster-stricken regions where traditional water sources are compromised. The researchers are exploring opportunities for scaling up production and integrating the technology into modular systems, potentially using solar panels for continuous operation.
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