A team of engineers from Australia and China has developed an innovative, sponge-like device that can capture water directly from the air and release it into a cup, powered entirely by sunlight.
This breakthrough technology, designed to work even in areas with low humidity, could provide a new solution for clean drinking water in regions that struggle with water shortages.
The water-from-air device was created by a team led by Dr. Derek Hao from RMIT University in Melbourne, in collaboration with Dr. Junfeng Hou from Zhejiang A&F University and five other Chinese research institutions.
The invention relies on refined balsa wood, which has a naturally spongy structure that has been specially modified to absorb moisture from the atmosphere and release it when exposed to sunlight.
The study detailing this invention was recently published in the Journal of Cleaner Production.
The sponge material is designed to fit into a cup that includes a dome lid, an anti-pollution tray, and a cooling mechanism.
The entire system is powered by solar energy, which activates the release of collected water into the cup.
Unlike other water-harvesting technologies like fog collectors or radiative cooling systems, this device works effectively across a broad range of humidity levels, from 30% to 90%, and temperatures ranging from 5 to 55 degrees Celsius.
Dr. Hao explained that their team developed a wood-based composite containing lithium chloride, iron oxide nanoparticles, and a carbon nanotube layer, all of which enhance the material’s water absorption and release capabilities.
The team also used artificial intelligence to predict and optimize how well the device could collect and discharge water under different environmental conditions.
Under laboratory conditions, the sponge device absorbed about two milliliters of water per gram of material at 90% humidity.
When exposed to sunlight, it released almost all the water it captured within 10 hours—more efficiently and at a lower cost than most existing methods.
Outdoor tests showed similar success, with the device collecting 2.5 milliliters of water per gram overnight and releasing most of it during the day, achieving a 94% water collection efficiency.
Even at low humidity levels of around 30%, the device still managed to absorb water at a rate of 0.6 milliliters per gram.
The design of the device draws inspiration from nature, using natural wood as the main material. This not only cuts costs but also improves water transportation due to its porous structure.
The material is durable too, remaining effective even after being stored at minus 20 degrees Celsius for 20 days. It also maintained its performance over ten consecutive cycles with less than a 12% decline in efficiency.
Dr. Hao noted that the current prototype is just 15 cubic millimeters in size, but scaling up production would be simple and cost-effective.
The team envisions using these spongy devices for emergency water collection in disaster zones where traditional water supplies are compromised. The material’s portability and reliance on solar energy make it ideal for off-grid use.
Looking forward, the researchers are in discussions with industry partners to move toward pilot-scale production and field testing.
They are also exploring ways to integrate the device into larger modular water-harvesting systems. Dr. Hao suggested that combining the technology with solar panels and thermal energy storage could enable continuous water collection, even in places with limited sunlight.
The team is also considering developing automated control systems with Internet of Things (IoT) sensors to monitor environmental conditions like humidity, temperature, and sunlight.
These advancements could make the water-from-air device even more efficient and accessible for people in need around the world.
Source: RMIT University.
