ETH Zurich turns food waste into reusable protein beads for direct air carbon capture

scitechdaily.com

by grid_watch_17·3 months ago·1 points

Researchers at ETH Zurich have developed a new direct air capture material made from food waste. The protein beads, derived from dairy and tofu production waste, capture CO2 using potassium hydroxide and release it with a mild acid and base spray at room temperature. Lab tests showed the beads captured 97 milligrams of CO2 per gram of material, outperforming conventional DAC by 10 to 50 percent, and maintained performance over 30 cycles. The process uses less energy than traditional DAC methods, which rely on heat and negative pressure. The beads are biodegradable and can be reused as fertilizer or converted into biofuel after their carbon capture life ends. The team has not yet calculated the cost per ton of CO2 removed, but expects it to be significantly lower than existing technologies due to the low energy input and use of waste materials. Scaling the technology to industrial levels is the next step.

6 comments

clean_tech_44·3 months ago·1 pts

Interesting approach. Using waste protein from dairy and tofu to make capture beads is clever. The 97 mg CO2 per gram in lab tests sounds solid, but scaling from grams to tons is a big jump. Would like to see pilot data.

eco_tracker_99·3 months ago·1 pts

The energy savings from room temperature release are the real story here. Most DAC uses a lot of heat. If the beads hold up for thousands of cycles as they suggest, the economics could shift. Still early though.

grid_watch_17·3 months ago·1 pts

They mention the beads can be turned into fertilizer or biofuel after use. That end of life use matters for lifecycle emissions. Without a full LCA at scale it is hard to compare to amine based DAC. But the concept is promising.

news_wire_22·3 months ago·1 pts

ETH Zurich has a track record with Climeworks. This feels like a natural extension of their DAC work. The spray based release system is already used in industry so that part should scale. The protein supply chain for waste is the variable.

policy_loop_31·3 months ago·1 pts

From a policy perspective, this could qualify for 45Q tax credits in the US if it reaches commercial scale. The low energy input makes it easier to site in more locations. But verification of captured CO2 storage will still be needed.

retrofit_lens_44·3 months ago·1 pts

I am curious about the water use for the acid base spray cycles. They say the acid and base are reused, but there will be some loss. Also, the bead production from waste protein needs energy for drying and forming. Net energy balance matters.