Capturing carbon dioxide (CO₂) from the air is a powerful way to fight climate change, but current systems face a major challenge.
The chemicals that are great at grabbing CO₂ from the air don’t easily let it go—and the ones that release CO₂ well aren’t great at capturing it. Fixing one part of the process often makes the other worse.
Now, a team of researchers at MIT may have found a clever solution using nanofiltration—tiny filters that sort particles by their charge.
Their approach could make carbon capture six times more efficient and cut costs by at least 20%, making it more practical for large-scale use.
Most carbon capture systems use a chemical called hydroxide, which bonds with CO₂ to create carbonate.
This is then sent into an electrochemical device where the CO₂ is released so it can be used to make fuel or other products.
But here’s the problem: both the capture and release steps use the same liquid solution.
The capture step needs a lot of hydroxide ions, while the release step needs carbonate ions. Because they’re sharing the same liquid, neither part can work at full efficiency.
To solve this, the MIT team added a third step between capture and release. After the hydroxide captures the CO₂, their special nanofilters step in.
These filters can separate hydroxide ions (which carry a single charge) from carbonate ions (which carry a double charge) with about 95% accuracy. The hydroxide goes back to capture more CO₂, while the carbonate heads to the next step to release it.
Without this filter, the release process loses efficiency. That’s because the acid in the system is supposed to react with the carbonate to release CO₂, but if there’s still hydroxide present, the acid just makes water instead.
The nanofiltration solves this problem by ensuring only carbonate moves forward.
This breakthrough doesn’t just improve performance—it also makes the system more stable and forgiving. Previously, small changes in the mix of chemicals could cause the whole process to become inefficient. Now, with nanofiltration, the system can handle variations without losing effectiveness.
The researchers estimate their method could reduce the cost of capturing CO₂ from $600 to around $450 per ton.
And since some buyers already pay more than $500 per ton for carbon credits, the new system could be economically viable right now. With further improvements, the cost might drop even more, opening the door for widespread use in both air and industrial emissions capture.
Ultimately, this innovation could help make carbon capture cleaner, cheaper, and more scalable for the future.
