Engineers have developed a sponge-like device that captures water from the atmosphere and releases it using solar energy, offering a potential solution for water scarcity in arid regions.
Key Points at a Glance
- Utilizes modified balsa wood infused with lithium chloride and iron oxide nanoparticles.
- Effective across humidity levels from 30% to 90% and temperatures between 5°C and 55°C.
- Demonstrated 94% water release efficiency in outdoor tests.
- Potential applications in disaster relief and off-grid water supply.
Water scarcity is one of the most pressing environmental challenges of our time, affecting more than 2 billion people worldwide. In a world where climate change is intensifying droughts and population growth is driving demand, researchers are racing to develop sustainable technologies that can ensure access to clean water. A new innovation from RMIT University could represent a major breakthrough. Their solar-powered, sponge-like device extracts water directly from the atmosphere—even in low humidity conditions—using nothing more than sunlight and specially treated wood.
At the heart of this technology lies an unlikely hero: balsa wood. Known for its lightness and natural porosity, balsa provides the ideal scaffolding for absorbing moisture. But the RMIT team, collaborating with Chinese institutions, has taken this humble material to a new level. Through a chemical process, they infused the wood with lithium chloride—a highly hygroscopic salt that can capture water vapor—and incorporated iron oxide nanoparticles and carbon nanotubes. These additions significantly enhance the material’s ability to both absorb and release water efficiently.
What sets this device apart from existing atmospheric water harvesters is its performance range. Many similar technologies are limited by specific humidity levels or require additional energy input to release the collected water. This device operates across a broad humidity spectrum—30% to 90%—and a temperature range of 5°C to 55°C. In lab conditions at 90% humidity, the treated material absorbed up to 2 milliliters of water per gram and released nearly all of it within ten hours under solar exposure. Even at just 30% humidity, it maintained a respectable 0.6 milliliters per gram, proving its resilience in arid environments.
In outdoor trials, the water release efficiency reached an impressive 94%. What makes this even more remarkable is that the device’s performance was stable across multiple cycles. Unlike many materials that degrade quickly under repeated exposure, this sponge retained its function after 180 cycles and even after 20 days of storage at -20°C. These features are critical for real-world applications, particularly in remote or emergency contexts where maintenance and resources are limited.
Scalability is another key advantage. The materials used are not only effective but also biodegradable and readily available, making mass production feasible and affordable. This opens doors to deploying the technology in developing countries, off-grid communities, or disaster-stricken regions where traditional water infrastructure is lacking or has been destroyed.
The research team is already envisioning next-generation applications. These include integrating the sponge into modular units powered by solar panels, and outfitted with IoT sensors to monitor environmental conditions in real time. Such systems could automatically optimize water collection cycles based on weather patterns and humidity fluctuations. In a world increasingly dependent on smart and adaptive infrastructure, this kind of synergy between material science and digital technology could be transformative.
There are, of course, challenges ahead. While initial tests are promising, long-term field studies across different climatic regions will be necessary to fully validate the technology’s robustness. There’s also work to be done in scaling up water output to meet larger community needs. But as a proof of concept, this solar-powered sponge already represents a leap forward—turning air into water without electricity, chemicals, or waste.
This innovation is a testament to how nature-inspired materials and clean energy can intersect to solve some of humanity’s greatest challenges. By harnessing the ambient moisture in the air, even the driest corners of the planet could one day have access to clean drinking water. For millions of people, that could mean not just a technological triumph—but a lifeline.
Source: RMIT University
