Engineers Create Sponge-Like Device That Captures Water from Thin Air and Then Releases it in a Cup

Photo credit: Shu Shu Zheng (RMIT University) | Xingying Zhang
Engineers from Australia and China created a sponge-like device that pulls water from thin air and releases it into a cup using sunlight. The device, developed by researchers like Dr. Derek Hao from RMIT University in Melbourne and Dr. Junfeng Hou from Zhejiang A&F University, is made from modified balsa wood mixed with lithium chloride, iron oxide nanoparticles, and a carbon nanotube layer.

It forms a spongy, porous structure that pulls in moisture from the air, even when humidity is low (down to 30%) and in a broad temperature range (5–55°C). When sunlight shines on it, the device releases the collected water into a cup, typically fitted with a dome lid and a cooling feature.

Brita UltraMax Large Water Dispenser With Standard Filter, BPA-Free, Reduces Copper, Cadmium and Mercury...

WATER DISPENSER: One BPA-free, large 27-cup Brita UltraMax Filtered Water Dispenser includes one Standard filter to help remove impurities from your...
CUTS OUT IMPURITIES: Brita water purifier dispenser cuts the taste and odor of chlorine and also reduces copper, mercury and other impurities
SUSTAINABLE: By switching to a Brita water filter system, you can save money and replace up to 1,800 single-use plastic water bottles a year

In lab tests, it grabs around 2 ml of water per gram of material at 90% humidity, letting out almost all of it in 10 hours under sunlight. Outdoor tests showed it gathering 2.5 ml per gram overnight with a 94% daily water collection efficiency. Even at 30% humidity, it still collects 0.6 ml per gram.

The prototype is small (15 cubic mm), with nine 0.8-gram sponge cubes producing 15 ml of drinkable water per cycle. It’s eco-friendly, uses inexpensive balsa wood, and is designed to be made in larger amounts. This makes it perfect for disaster zones or dry areas with scarce water, since it only uses sunlight and is simple to transport. The team is exploring ways to add solar panels, thermal storage, and IoT sensors for automatic, round-the-clock use.

Artificial intelligence was used to forecast and boost the device’s performance in various weather conditions, making it work better than other approaches like fog harvesting or radiative cooling.

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. 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,” said Dr Derek Hao, Senior Researcher from RMIT University in Melbourne.

[Source]