ETH Zurich removing CO2 from the atmosphere with new method

In Switzerland, researchers at ETH Zurich are developing a new method to remove CO2 from the atmosphere. It involves molecules that become acidic when exposed to light. Their new process requires much less energy than conventional technologies.

Scientists are exploiting the fact that in acidic aqueous liquids, CO2 is present as CO2, but in alkaline aqueous liquids, it reacts to form salts of carbonic acid, known as carbonates. This chemical reaction is reversible. A liquid’s acidity determines whether it contains CO2 or a carbonate.

To influence the acidity of their liquid, the researchers added molecules, called photoacids, to it that react to light. If such liquid is then irradiated with light, the molecules make it acidic. In the dark, they return to the original state that makes the liquid more alkaline.