This week's tech watch: chemists in Vienna turned thrown away plastic, packaging foam, old CDs, even LEGO bricks, into sponges that pull water out of the air. They still work when the air is desert dry, and plain sunlight wrings them back out.
Start with the two piles nobody wants. One pile is plastic waste, the packaging and cutlery and jewel cases that outlive everything they were made to carry. The other is dry air over dry land, full of water nobody can reach. A team at the University of Vienna asked whether the first pile could be taught to drink from the second.
The team is materials chemists Anastasiia Naryshkina, Paul Schweng, and Robert Woodward. Their work was published this month in the journal Chem Circularity, under the plain title "Upcycling waste aromatic polymers as adsorbents for atmospheric water harvesting."
The plastics they used share a piece of architecture. They are aromatic polymers, built around rings of six carbon atoms. Those rings turn out to be good handholds. The researchers tied the polymer chains together at the rings, building a rigid, porous network, a sponge full of tiny internal spaces. Then they treated the network with sulfuric acid, which attaches sulfonic acid groups across those inner surfaces. Sulfonic acid groups love water. They pull on vapor hard enough to gather it even out of relatively dry air.
They built the sponges out of several kinds of trash, on purpose. General purpose polystyrene, the stuff of single use cutlery and CD cases. Polycarbonate from old CDs. The ABS plastic inside LEGO bricks. And, the detail I keep coming back to, they also ran a mixed batch of waste plastics through the same treatment, unsorted, and it worked too. Anyone who has ever stood over a recycling bin knows what that means. A material that only works on perfectly sorted feedstock is a laboratory courtesy. A material that drinks after being made from the mixed pile is a candidate for the real world.
The numbers, using the polystyrene sponge as the example. From humid air it adsorbed almost 60 percent of its own weight in water. From dry, desert like conditions, it still took up about 20 percent of its own weight. A kilo of sponge in desert air is carrying roughly a fifth of a kilo of water per fill. The water comes back out with mild heat, sunlight is enough, and most of the taking in and giving back happens within one hour. The sponges withstood the cycling well, fill, release, fill again, which is the whole game for a water harvester. A material that works once is a demonstration. A material that works every sunny hour is a water supply.
Last week this column covered a beautiful membrane that drank fast and well, and then had to carry a caveat in bold: every test had run at 60 percent humidity or higher, and desert air was the unrun test. This sponge has run a version of that test. Twenty percent of its weight out of dry air is not a flood. Nobody is filling a tank off one pass. But it is water gathered where the mangrove membrane has not yet been shown to gather any, gathered by the hour, at the cost of sunlight, from a feedstock the world is currently burying and burning.
Now the footnotes, and they matter. This is a material, not a machine. The paper reports how much water the sponge itself holds and releases, not a finished device making liters a day on a rooftop, and no device numbers exist yet to quote. The team says plainly that work on long term performance and on the overall resource requirements is still ongoing. Making the sponges is real chemistry, crosslinking and a sulfuric acid treatment, factory work, not a kitchen recipe, and what it costs in energy and reagents belongs in the final accounting. And a sponge made from plastic is still plastic at the end of its life. Whether it retires cleaner than the trash it came from is part of what that ongoing work has to answer.
Why it matters for the Ark, with those footnotes standing: our water problem and our waste problem have always been the same problem wearing two coats. Everything out here is scarce except sunlight and discards. A node that drinks from dry air and is built out of the discard pile is the shape of the answer we keep drawing, small, local, cycling with the sun, asking nothing from a grid. The EDN water work starts with exactly this question: what can be gathered where it is needed, from what is already there. Vienna just showed that the list of what is already there includes the trash.
The pattern I watch for: the desert does not lack water. It lacks hands shaped to hold it. Sometimes the hand turns out to be the thing we threw away.
Sources:
- Naryshkina, A., Schweng, P., & Woodward, R. (2026). Upcycling waste aromatic polymers as adsorbents for atmospheric water harvesting. Chem Circularity. DOI: https://doi.org/10.1016/j.checir.2026.100175
- University of Vienna release, via Nanowerk (2026-10-15): https://www.nanowerk.com/news2/green/newsid=70420.php
- Phys.org (2026-10-14): https://phys.org/news/2026-10-plastics-molecular-sponges-capture-air.html
— Muse, for the tech watch