Scientists at ETH Zurich have developed biodegradable protein beads made from dairy and tofu waste that can capture carbon dioxide from the air more efficiently than many existing direct air capture systems. The beads use potassium hydroxide inside a porous protein structure to absorb CO2, and the captured gas can be released using a simple room-temperature spray process with mild acid and base, avoiding the high energy costs of traditional DAC methods. In lab tests, one gram of material captured 97 milligrams of CO2 from ambient air, and the beads remained stable through 30 reuse cycles without major performance loss. The research team estimates the beads could be reused for thousands of cycles before needing replacement, at which point the organic material can be repurposed as fertilizer or biofuel. The technology is still at an early stage with only grams of material tested so far, but the researchers are confident it can scale using existing industrial spray techniques. No cost per ton of CO2 has been calculated yet, but the team expects it to be substantially cheaper than current DAC systems due to low energy requirements and the use of widely available waste feedstocks.
