University of Vienna chemists converted polystyrene packaging, old CDs and LEGO bricks into porous materials that absorbed up to nearly 60 percent of their weight in water from humid air.
Two of the world’s pressing problems may have a shared solution. Billions of people face water scarcity for at least part of the year, while plastic waste accumulates in landfills and the environment. Researchers at the University of Vienna have found a way to turn one into a tool for addressing the other.
In a study published in Chem Circularity, materials chemists Anastasiia Naryshkina, Paul Schweng and Robert Woodward describe how they converted waste plastics into porous, water-attracting materials that can capture moisture from the air and release it again with mild heat.
Plastics with rings
The team focused on aromatic polymers, plastics whose molecular chains contain six-carbon rings. Several common plastics fall into this category, including polystyrene, used in packaging and disposable foam containers; polycarbonate, used in CDs and DVDs; and acrylonitrile butadiene styrene, or ABS, the hard plastic from which LEGO bricks are made.
The researchers used polystyrene packaging, polycarbonate CDs, ABS LEGO bricks and a mixed selection of waste plastics as starting materials. They first transformed the plastics into porous polymer networks, sponge-like structures riddled with tiny holes that provide a large internal surface area.
Next, they treated the networks with sulfuric acid. That step attached sulfonic acid groups to the aromatic rings. These chemical groups strongly attract water molecules, turning the porous plastics into effective water collectors.
Pulling water from thin air
The approach is known as atmospheric water harvesting. The air holds an enormous amount of water vapor, even in dry regions, and materials that can capture it offer a way to produce drinking water without rivers, wells or desalination plants.
Earth’s atmosphere holds roughly 13 trillion tons of water at any given moment. People have long tried to tap it. Fog nets strung across hillsides in Chile, Morocco and elsewhere capture droplets from passing clouds, but they work only where fog is frequent. Absorbent materials offer the possibility of harvesting water even from clear, dry air.
In tests, the polystyrene-based sponge absorbed almost 60 percent of its own weight in water from humid air. Under dry, desert-like conditions, it absorbed about 20 percent of its weight.
Speed matters as well as capacity. Most of the capture and release took place within an hour, and mild heat, such as that provided by sunlight, was enough to drive the water back out. That combination could allow a device to run several cycles a day, collecting moisture during humid nighttime hours and releasing it when the sun warms the material.
The ability to work in dry air is the key test for such materials. In humid climates, water can often be collected by simpler means, such as condensing moisture on cold surfaces, though that typically requires electricity. In arid regions, where clean water is scarcest, the air holds less moisture, and only materials with a strong attraction to water can pull out useful amounts.
The sponges also held up over repeated capture-and-release cycles, an important requirement for any practical device.
Competing with designer materials
Atmospheric water harvesting has attracted growing research interest. Some of the most effective materials studied so far are metal-organic frameworks, crystalline structures that can be designed with pores precisely tuned to capture water. The chemist Omar Yaghi, who pioneered these materials, shared the 2025 Nobel Prize in Chemistry for their development, and his group has demonstrated devices that harvest water in desert air.
Such materials can be expensive and complex to produce, however. Making water-harvesting sponges from waste plastic could offer a cheaper route while also giving discarded materials a second life. The approach falls under what chemists call upcycling, converting waste into products of higher value rather than simply recycling it into lower-grade materials.
A different kind of plastic recycling
Plastic recycling rates remain low worldwide. Much plastic waste is landfilled, burned or leaked into the environment, and mixed or contaminated plastics are particularly hard to recycle. Polystyrene foam, for example, is bulky and lightweight, which makes it costly to collect and process, and it is rarely recycled in many places.
The Vienna team’s method worked not only on individual types of plastic but also on a mixture of waste plastics, a potentially important advantage, since sorting plastics by type is one of the main barriers to recycling.
Questions to answer
The research is at an early stage. The release notes that long-term performance and the resources required for the process are still being studied. The treatment uses sulfuric acid, a hazardous chemical, and any large-scale application would need to account for the energy, chemicals and waste involved, as well as the safety of drinking water produced by plastic-derived materials.
Researchers will also need to show that the sponges can produce useful quantities of water in real-world devices and that their performance holds up over months or years of use. Laboratory tests under controlled humidity do not always translate directly into field conditions.
Still, the study points to an intriguing possibility: that the plastic packaging, old discs and broken toys piling up in landfills could one day help supply water to the places that need it most.
Notes
- Naryshkina, A., Schweng, P., and Woodward, R. “Upcycling Waste Aromatic Polymers as Adsorbents for Atmospheric Water Harvesting.” Chem Circularity, 14 October 2026. DOI: 10.1016/j.checir.2026.100175.
- University of Vienna. “Waste plastics become molecular sponges that capture water from air.” EurekAlert!, 14 October 2026. https://www.eurekalert.org/news-releases/1147685.
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