Turning over a new leaf with artificial photosynthesis for carbon capture

Plants take in carbon dioxide and give off oxygen through their respiration. You might say they’re the original, natural carbon capture system.

Scientists at the University of Illinois Chicago and Argonne National Laboratory are on a team that created an artificial leaf that does just that: acts like a carbon capture system. 

This isn’t the first project to harness the power of artificial photosynthesis for carbon capture. Argonne scientists have been working on the concept for a while. And others, like Purdue University researchers, are leveraging artificial photosynthesis for efficient energy production.

But the Illinois invention reportedly is different from other designs because it actually works in the real world, not just the lab. Plus, it captures 100 times more carbon and uses less power than a 1-watt LED lightbulb.

The innovation

An illustration of the carbon capture process.
An illustration of the carbon capture process. Credit: Aditya Prajapati / University of Illinois Chicago

The engineers used inexpensive materials to modify an existing artificial leaf system so it had a wet and a dry side separated by an electrically charged membrane.

An organic solvent on the dry side attaches to captured carbon dioxide to create bicarbonate, or baking soda, on the membrane. As the bicarbonate builds up, negatively charged ions are pulled across the membrane to the wet side. The liquid dissolves the bicarbonate and it becomes a concentrated CO2, which can be used for fuels or other uses.

The electric charge speeds the transfer of molecules across the membrane. It’s such a low level of electricity that this device is far more energy efficient than other carbon capture methods. The researchers call their innovation an “ultrafast” and continuous way to capture CO2 at ambient conditions.

The UIC scientists discovered this device has a very high rate of carbon capture compared to surface area. It’s so significant they refer to it as “unprecedented” in their research paper. The device is small enough to fit in a backpack and processes carbon more than 100 times better than other systems.

This research is funded by a U.S. Department of Energy grant. One of the grant stipulations is that the system should not cost more than $200 per ton of carbon dioxide. The UIC team’s technology costs an estimated $145 per ton.

What’s next

The researchers didn’t specify their next steps toward commercialization. However, UIC already has filed for a patent.

The researchers did give ideas about future applications for their innovation. The device could be stackable and scalable to meet residential carbon capture needs as well as at industrial facilities.

“The modules can be added or subtracted to more perfectly fit the need and affordably used in homes and classrooms, not just among profitable industrial organizations,” Meenesh Singh, assistant professor of chemical engineering at UIC, said in a news release. “A small module of the size of a home humidifier can remove greater than 1 kilogram of CO2 per day, and four industrial electrodialysis stacks can capture greater than 300 kilograms of CO2 per hour from flue gas.”