Imagine turning seawater into safe drinking water using only sunlight and a sponge-like material. Sounds simple, right? Researchers have now created exactly that, a new way to desalinate water that's easy, energy-efficient, and sustainable.
This isn’t just a paper chain—it’s a 3D-printed material designed to absorb seawater and transform it into purified, salt-free water. (Credit: Adapted from ACS Energy Letters 2025, DOI: 10.1021/acsenergylett.5c01233)
Could a Sponge Solve the World's Water Crisis?
Desalination, the process of making seawater drinkable, typically uses large amounts of energy, making it expensive and challenging to sustain. But a team of researchers, as reported in ACS Energy Letters, has designed a unique sponge-like material filled with microscopic air pockets that harnesses sunlight to turn salty ocean water into clean, drinkable freshwater.
This innovative material is an aerogel—a type of sponge with solid, tiny pores—that efficiently evaporates water when heated by the sun, leaving the salt behind.
From Microscopic Pores to Drinking Water
The scientists created their sponge by combining carbon nanotubes and cellulose nanofibers, printing the mixture onto a frozen surface layer-by-layer. This technique resulted in evenly spaced, tiny vertical holes, each just about 20 micrometres wide. Remarkably, the aerogel maintained its effectiveness even when scaled up to larger sizes, a common limitation of previous aerogel technologies.
In outdoor tests, researchers placed the aerogel into a seawater-filled container topped with a simple plastic cover. When sunlight heated the material, clean water vapour rose and condensed onto the plastic, dripping into a collection funnel. After just six hours in the sun, the setup produced approximately three tablespoons of freshwater—proving the concept works.
Towards an Energy-Free Water Future
According to researcher Xi Shen, their aerogel allows full-capacity desalination at any size. This scalability suggests that, in the future, communities worldwide could benefit from this affordable and sustainable method of producing drinking water.
With fresh drinking water increasingly scarce in many regions, this sun-powered sponge might be a critical step toward a future where desalination becomes simpler, cheaper, and more widely accessible.
If you are interested in more details about the underlying research, be sure to check out the paper published in the peer-reviewed journal ACS Energy Letters, listed below.
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