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.
That's a screamer. I remember them at 110, then 300, super-sized to 600...
Probably made of toxic materials, but it works!
Nay! Use this instead:
“That’s a screamer. I remember them at 110, then 300, super-sized to 600...”
Yes.. Dial up with a phone that you placed the receiver in a holder to transmit and receive.
I learned COBOl, Fortran and Assembler on 80 column punched cards in the mid 1970’s! That was sadistic.
For salt water you need to up the ante:
“With climate change and population growth occurring simultaneously, innovations like this water-from-air harvester provide a glimmer of hope.”
LOL however we need out of the box thinking. Not sure this is it but they are trying.
I can make a cup or two of water every so often, because I’m a Wizard.
A whizzer Wizard. The Yellow Wizard of MiddleEarth.
A movie, includig the binary language of moisture vaporators.
I did so as well in the same time frame. You are such a fossil!
Most of that process was hands-on with an IBM 1130, with a smattering of 360/45 through the window. I finally threw out that old acoustic-coupler modem I have been hoarding.
lithium chloride, iron oxide nanoparticles, a carbon nanotube layer which you will be drinking along with the H20
2.5 milliliters of water is about half a teaspoon... Might be better than nothing if you’re crawling across an African desert. Then again...
“I don’t believe that there’s a sufficient supply of balsa wood in the world to make this practical on a large scaleyou can use alkali to take the lignin out of any softwood they all have the same channel like structures in them. It’s the cellulose remaining you are after. There is nothing unique about balsa cellulose. You could even dissolve cellulose from hardwoods into liquid ether and make a solid foam with it literally like a cellulose sponge you can buy at Wal-Mart. The secret sauce is the lithium chloride which has a powerful hydrophilic property.
2.5 grams per gram of material is high even 0.6 grams is good per every gram of material. Water is 1 gram per milliliter so a single kilo would make 2.5 liters or 0.6L per night the WHO says 20 liters is the minimum per day for hydration, and hygiene.
If you look at this source for the same material you see 9 one centimeter sizes cubes pulled out 15ml that’s over a ml per cubic centimeter of material.
https://newatlas.com/materials/spongy-drinkable-water-thin-air/
To make 20 liters would than take 20,000 cubic centimeter of material at only 1 ml per cubic centimeter. That’s a cube 28cm on each axis or slightly less than 12 king’s thumbs freedom units one each side.
Forget solar heating just use electric heat and a blower fan into a cooled condenser plate. I get that they wanted to prove it could work just by solar energy alone but for real world the material itself is the breakthrough feed it energy the modern human way with electrons from any source that is energy dense. I guess you could still use solar panels at 30% photons to electrons and make a crap ton of water given how much this material absorbed vs it’s mass.
“2.5 milliliters of water is about half a teaspoon... Might be better than nothing if you’re crawling across an African desert. Then again...”
2.5ml of water from a cubic sugar cube sized cube that’s 2.5 times it’s mass in water vs the material itself. Scale that up to a cubic meters of material. That’s 100*100*100 centimeter of material. That’s a million cubic centimeters. At 2ml of water per gram of material @90% humidity that’s 2:1 water to material mass. 1ml=1gram at STP even at 0.6ml to the gram that’s 0.6:1
You are only seeing the amount a tiny cube made scale that up a million times into cubic meter sized amounts. The material is not hard to make its deligninfied wood, lithium chloride salts and iron. If you heat it externally you don’t need the carbon nanotubes the lithium chloride is what is hydrophilic , if you leave are lithium chloride salts open to air they rapidly turn to liquid brines.
“lithium chloride, iron oxide nanoparticles, a carbon nanotube layer which you will be drinking along with the H20”
No you are drinking the H2O vapor that condenses once driven off the material ,lithium chloride,iron oxide nor carbon would vaporize at the low temps the solar heat would make far less than 100C. If you really wanted to be sure you could put a nanopore hydrophobic vapor membrane that only would allow individual H2O molecules in vapor form past it and the condenser on the other side of it. This is the same process as heating salt water to a vapor an condensing it for desal it’s how you make industrial quantities of distilled water as well. So no you won’t be drinking any of those materials in fact it would be distilled water grade and you would need to add minerals as drinking distilled water is bad for your bones and teeth. Calcium carbonate or calcium chloride, magnesium chloride as well are your drinking minerals go look at a bottle of nestle water or smart water. They both start out as distilled with added minerals.
Those were the droids we were looking for....
Lithium chloride in its pure salt form can pull water from the air down to single digit relative humidity levels it turns to brines if you leave a mass of it out even in the driest desert air. The problem has always been getting the water back out you have to heat it or pull. Vacuum on it and it’s a thick brine liquid that flows everywhere. Having it trapped in cellulose foam effectively keeps it right in the absorption location while also allowing gas to flow past it while saturated. Heat that gas above the Gibbs energy level holding the H2O to the LiCl and you get back your H2O in vapor form along with that heated gas stream which would rapidly saturate that closed gas stream...pass that over a cooler surface below the dew point of your saturated gas mixture and Bob’s your uncle pure distilled water runs down. <<<>this is the way. It’s neat to use solar heating for the greenwashing of it. Forget that use an electric joule heater, and blower fan over to a liquid cooled condenser. With a couple cubic meters worth of this foam you can pull hundreds to thousands of liters per day, no need for day night cycles either it’s how long yo saturate the wood foam and how long to hear drive it off. The whole day night cycle is because they are using solar heat. Joule heating would have much higher heating rate so that ten hours to vaporize it all would be less a lot less as the temps went up, above 100C it would be nearly instant it comes down to the thermal mass of the material and latent heat of vaporization.
Yep. A Ferrari is a long way from a Model T.
https://www.rmit.edu.au/news/all-news/2025/may/spongy-water-harvester
“With nine sponge cubes, each weighing 0.8 grams, 15 milliliters can be absorbed and released into the cup.
“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%,” Hou said.
“At 30% humidity, our device absorbed water at about 0.6 milliliters per gram.”
They don’t give the density of the material but they do show those 9 cubes in the palm of a average sized man. At 0.8grams each. They are between one cm or two cm on each side based on that hand for scale. Wish they had a banana for scale....I digress
At 1.5 cm per side that’s 3.375 cubic centimeters at 0.8 grams or 0.23g/cm^3. One cubic meter of this material would mass out at 237,037 grams at 2.5 grams H2O per gram of material = 592,592 grams of H2O...@1000g/L that’s over 590 liters of water that is for a single cubic meter of this material. Even at 0.6ml/g that’s still 142 liters of water. The average washer/dryer is smaller than a cubic meter in size.
Here again forget solar heating make this into sheets one of these cubes thick by 2 meters by 1.8 by 2.4 meters panels...That’s 6 foot by 8 foot freedom units. At 1.5*1.5cm on a side you fit 19,200 of those cubes on a single flat panel. 9 of them made 15ml, 19,200 would make 32,000ml now stack those panels side by side in a shipping container the 8 foot’m dimension is the up and the 6 foot is the deep a 53 foot container would hold 8 panels deep. Allowing for one missing panel width between panels is 1.5cm spacing. Thats 83 panels across. So 84*8= 664 panels @32L each is 21,248L per cycle not a small amount from a container you could ship anywhere via trucks. Charge it by pumping air through it via a hole at one end and a blower, when it’s saturated close the air loop with a second shipping container that holds the blower the joule heating element and the cooled condenser and water storage tank. Two side by side with simple air hoses between them. Loop the heated gas until the humidity being released is below the dew point in the condenser then stop the heating and blow more outside air through the absorption panels until they saturate again...wash ,rinse and repeat. You could get multiple cycles per day again forget solar use modern heating and condenser methods.
Honestly, I thought my first was a 400…(1986 or so) but I couldn’t remember and I just figured I was old. LOL
According to the NCESC, humidity in the Arabian Deserts ranges from 5% to 95%. A post from the same site states that humidity in the Atacama Desert ranges from 15-40%. According to a friend who lives in the Sonoran Desert of Arizona, the humidity range is similar to that of the Arabian Desert, with high humidity occurring primarily during the rainy season (intermittently July through September).
So no, in the desertthe device would work poorly or not at all during big chunks of the year.
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