Researchers at ETH Zurich have developed biodegradable beads from dairy and tofu production waste that capture carbon dioxide from the air more efficiently than many existing methods. The protein-based material releases the gas at room temperature with minimal energy use.
The beads are made by extracting proteins from whey and tofu byproducts, forming them into amyloid fibrils, and combining them with potassium hydroxide. In lab tests, one gram of the material captured 97 milligrams of CO2 from ambient air, outperforming conventional direct air capture technologies by 10 to 50 percent.
The process uses a simple spray of mild acid and base at room temperature to release the captured CO2, avoiding the high heat and energy demands of traditional systems. The beads remained stable through 30 capture-and-release cycles.
Lead researcher Raffaele Mezzenga said the approach relies on widely available waste and requires little energy, which could make it substantially cheaper than current methods. The team has not yet calculated exact costs per ton of CO2 removed.
The material is non-toxic and biodegradable, allowing it to be repurposed as fertilizer or biofuel once its capture capacity declines after several thousand cycles. Further testing is needed to assess performance at industrial scale.
