Dairy and tofu waste can become powerful carbon traps, Swiss scientists find

3 min readNew DelhiUpdated: Jun 18, 2026 01:39 PM IST

Researchers at ETH Zurich extracted proteins from waste dairy byproducts and combined them with potassium hydroxide in an elaborate process to make porous beads. (File Photo)

Protein-rich waste liquid from tofu or dairy production could be made into beads that capture carbon dioxide from the atmosphere, researchers at a Swiss institute have found.

The researchers at ETH Zurich extracted proteins from dairy waste byproducts and combined them with potassium hydroxide in an elaborate process to produce porous beads.

Large amounts of protein-rich liquid are generated during dairy and tofu production, of which only a portion is reused in food manufacturing, while the rest is thrown away.

The process of capturing carbon dioxide from the atmosphere is called Direct Air Capture ( DAC), and a spinoff of ETH Zurich was the first to bring this technology to the market.

The research published in the journal Proceedings of the National Academy of Sciences (PNAS) was led by materials scientist  Raffaele Mezzenga.

The study said the carbon capture material from dairy and tofu waste performed better in lab tests than existing market technologies.

Why the world needs carbon capture materials

According to the Assessment Report from the Intergovernmental Panel on Climate Change, the world will  need technologies capable of removing and safely storing hundreds of billions of tons of carbon dioxide already present in the atmosphere.

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Researchers and startups have spent years working to improve these systems.  Climeworks, an ETH Zurich spin-off, is one of the earliest commercial players.

Direct air capture, though, still remains an expensive process that requires a significant amount of energy to run.

How the beads work

When exposed to air, the potassium hydroxide inside the beads reacts with carbon dioxide and converts it into hydrogen carbonate. This chemical reaction removes carbon dioxide from surrounding air.

“The resulting material is like a sponge that can absorb large quantities of CO2 via the potassium hydroxide,”  said researcher Raffaele Mezzenga.

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The beads can be reused as many as 30 times with no significant decline in efficiency.

Protein beads work better than conventional technologies

In their tests, researchers were able to extract 97 milligrams of CO2 with one gram of protein beads. Which would theoretically mean that they can capture nearly 100 grams of CO2 with one kilogram of the material.

They said this exceeded  the capacity of conventional DAC technologies by 10 to 50 per cent.

(This article has been curated by Paramita Datta, who is an intern with The Indian Express)