Posted on 05/10/2025 7:17:29 AM PDT by Red Badger
A pair of tweezers squeezes water from the spongy material developed by the team. (Credit: Xingying Zhang)
In a nutshell
This wood-based material can pull water directly from air using only sunlight, working even in arid regions with humidity as low as 30% and in freezing temperatures down to -20°C.
The device captured 2.5 milliliters of water per gram overnight in real-world testing, releasing it when exposed to sunlight with 94% efficiency.
Made from affordable materials like balsa wood and lithium chloride, this technology could provide clean drinking water in areas lacking infrastructure or during emergencies.
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MELBOURNE — Love a fresh glass of water? Someday soon, it could come straight from the air around you, collected by a small wooden cube sitting on your windowsill.
Scientists at The Royal Melbourne Institute of Technology (RMIT) in Australia have created a remarkable new material that does exactly this – it pulls moisture from the atmosphere and releases it as clean drinking water when exposed to sunshine. No pipes, no electricity, no infrastructure needed.
Nearly 80% of people worldwide now face serious water security issues, making this invention potentially life-changing for millions. The technology could help communities in water-scarce regions produce their own drinking water from nothing but air.
“Billions of people around the world lack access to drinkable water, and millions die from water-borne diseases every year,” said Dr. Derek Hao, a materials scientist and environmental engineer in RMIT University’s School of Science, in a statement. Hao and fellow RMIT researchers collaborated with Chinese scientists from Zhejiang A&F University, Yancheng Institute of Technology, and the Hangzhou Vocational & Technical College.
How It Works: Nature’s Design with a High-Tech Twist
The science behind it is cleverly simple. Researchers started with balsa wood, which naturally contains tiny channels that once carried water when it was a living tree. They removed lignin (the compound that makes wood rigid) to create a spongy structure packed with microscopic pores. This framework was loaded with lithium chloride salt, which strongly attracts water molecules from air. One side was then coated with carbon nanotube ink that converts sunlight into heat.
“Our team has invented a device comprising wood’s spongy scaffolding, lithium chloride, iron oxide nanoparticles, a carbon nanotube layer and other specialized features,” Hao said.
At night, the material absorbs moisture from the surrounding air. When the sun rises, the coating heats up, forcing the absorbed water to evaporate and condense as liquid water that can be collected for drinking.
Most atmospheric water harvesters only work in humid environments, but this new device functions in relative humidity as low as 30% – dry enough for desert regions where water shortages hit hardest. It continues working even in freezing temperatures down to -20°C (-4°F), something no previous material could manage.
“The device retained its flexibility and water-absorbing function even after being stored at −20 degrees Celsius for 20 days, demonstrating excellent freeze resistance,” Hao noted.
Breaking Records: Performance That Surprises Experts
The scientists used artificial intelligence to refine their creation. They analyzed over 600 data points with machine learning algorithms to identify which factors most affected water collection efficiency. Their models revealed that absorption time, salt concentration, and humidity were the key variables to optimize.
The wood-based composite developed by the team for their research fit snugly into a cup with a dome lid and anti-pollution tray, a cooling mechanism and an activation system powered by the sun.
When tested outside by the Chinese team, a small prototype pulled impressive amounts of water from air with 65.9% humidity. “In outdoor tests, our device 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%,” said Dr. Junfeng Hou from Zhejiang A&F University.
“At 30% humidity, our device absorbed water at about 0.6 milliliters per gram. These results highlight its potential use in off-grid, solar-driven water harvesting systems,” added Hou, who led the Chinese research team.
Lab tests showed even better performance. Under controlled conditions with 90% humidity, the material absorbed 2.18 grams of water per gram of its own weight. When exposed to concentrated sunlight, it released up to 99.9% of the collected water.
The wooden framework prevents a persistent problem with salt-based water collectors: leakage. Previous designs struggled because moisture-absorbing salts would dissolve and drip away after capturing enough water. This new design holds the salt in place through repeated wet-dry cycles.
“Its moisture absorption–release performance was stable across 10 consecutive cycles, with less than 12% decline in efficiency,” Hao said.
The material also shows surprising toughness. It can be compressed repeatedly and return to its original shape, maintaining 87% of its height even after 20 compression cycles. This resilience indicates it could withstand rough handling in real-world settings.
Beyond Drinking Water: Wide-Ranging Applications
This technology opens possibilities beyond just drinking water. It could potentially irrigate crops in arid regions, control humidity in buildings, or even cool solar panels to improve their efficiency.
Hao said the device would be particularly valuable in emergency scenarios: “Its ability to harvest potable water from the atmosphere using only sunlight makes it invaluable in disaster-stricken areas where traditional water sources are compromised. The system’s portability and reliance on renewable energy further enhance its applicability in such contexts.”
The researchers are already looking toward scaling up production. “The current demonstration unit size is 15 cubic millimeters. It would be very easy to prepare a larger unit, or we can use the units to form an array,” Hao explained. “The main component, balsa wood, is widely available, biodegradable and cheap, and the manufacturing process is not complex, which could enable mass production.”
With climate change and population growth occurring simultaneously, innovations like this water-from-air harvester provide a glimmer of hope. With further development, this unassuming wooden cube could help communities leapfrog traditional water infrastructure altogether—producing clean drinking water literally out of thin air.
Paper Summary
Methodology
The researchers created their wood-based atmospheric water harvesting material through several steps. First, they treated balsa wood with sodium chlorite to remove lignin, creating a porous wood sponge. This sponge was then impregnated with lithium chloride (LiCl) solutions at different concentrations (0-30%). They also developed a photothermal ink containing multi-walled carbon nanotubes, iron oxide, and cellulose nanofibrils, which was applied to one surface to create a solar-thermal interface. The team tested the material’s performance in absorbing moisture under varied conditions (humidity 30-90%, temperature 5-55°C) and releasing water under different light intensities (0.6-1.5 times natural sunlight). They built a solar-powered atmospheric water harvesting device to evaluate real-world performance in natural day/night cycles. Additionally, the researchers employed machine learning techniques, including random forest models and long short-term memory (LSTM) networks, to analyze and predict the material’s absorption-desorption behavior based on over 600 data points.
Results
The wood-based material demonstrated exceptional water harvesting capabilities across a range of conditions. At 90% relative humidity, it absorbed 2.18 grams of water per gram of its own weight within 600 minutes. When exposed to simulated sunlight, it released up to 99.9% of the absorbed water when illuminated at 1.5 times natural sunlight intensity. The material functioned effectively at humidity levels as low as 30% and maintained performance even at temperatures as low as -20°C due to the salt’s ability to prevent water from freezing. In outdoor testing under natural conditions (65.9% humidity), the prototype device absorbed moisture overnight and released it during the day with approximately 94% efficiency. After 10 absorption-desorption cycles, the material maintained about 80% of its initial water collection capacity. The machine learning models achieved high prediction accuracy (R² of 0.988) for moisture absorption rate, enabling optimization of the material’s composition and performance.
Limitations
The research has several practical limitations. The outdoor tests were conducted in relatively humid conditions (65.9% relative humidity), so performance in extremely arid environments remains untested over extended periods. While the researchers optimized the lithium chloride concentration to minimize leakage, there could still be long-term concerns about salt loss after extended use beyond the 10 cycles tested. The water production rate might be insufficient for larger-scale applications without significant scaling up. Additionally, economic feasibility and environmental impact of large-scale production weren’t addressed, which would be critical factors for real-world implementation. The researchers also noted that at higher salt concentrations, excessive water absorption led to leakage issues, limiting the optimal concentration to 15% lithium chloride.
Funding and Disclosures
The research was supported by the National Natural Science Foundation of China (32201492), Zhejiang Province Intergovernmental Scientific and Technological Innovation Cooperation Project (2022C04008), and contributions from RMIT Sustainable Development Research Grants. The authors declared no conflicts of interest in relation to the research.
Publication Information
The study, titled “Development and characterization of novel wood-based composite materials for solar-powered atmospheric water harvesting: A machine intelligence supported approach,” was published in the Journal of Cleaner Production (Volume 497, February 2025). The research was conducted by a team led by Xingying Zhang, Yangyang Xu, and Junfeng Hou from Zhejiang A&F University in China, with collaborators from Yancheng Institute of Technology, Hangzhou Vocational & Technical College, and RMIT University in Australia. The article was received in November 2024, accepted in February 2025, and published online on February 28, 2025.
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15 cubic millimeters? That is the size of a BB. You would lose that in a puff of wind.
Nice idea, but too small to be of any interest. Scale it up to a cubic foot. THEN, I’d pay some attention.
Be still, my heart. This device will save us all. I wonder who the Chinese stole it from?
just carry a house- sized block of this crap with you into the desert, and after dealing with the lithium— wth- then you’re good!
Scale it up to provide several gallons over night and then I’ll be interested.
And an added benefit is a little lithium to stabilize the moods of the people using this technology.
We’ve seen this movie before. Don’t invest your kids inheritance on this as a start up investment.
Is 30% humidity really arid?
Any way to get clean drinking water to the world is always a good plan.
I remember a 1200 baud modem. It was a start. A few years later we are using 2GB fiber connections.
These things take time.
I marvel at the large amounts of water my dehumidifier collects.
Cooling? Compressor based cooling? Peltier thermoelectric? Passive radiator with a fan? The first two can gather water without the balsa wood part.
OK, I reread the no electricity required in the headline, but does that apply to the whole system or just the balsa wood part?
Sounds like a possibility. But what are the environmental impacts of production and disposal?
I don’t believe that there’s a sufficient supply of balsa wood in the world to make this practical on a large scale.
It needs sunlight so it doesn’t do anything at night.
This would have helped Saul Goodman and Mike Ehrmentraut while they were walking through the New Mexico desert with that 7 million dollars.
There's always that.
“Its moisture absorption–release performance was stable across 10 consecutive cycles, with less than 12% decline in efficiency,”
so, what would be the decline in efficiency after 100 cycles?
scaling it up would be the point.
Should be added to your escape kit/lifeboat supplies: potable water will keep you alive.
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