Light-Activated Photoacid Triggers CO2 Release (VIDEO)
Caption
Using light instead of heat, researchers at the Department of Energy’s Oak Ridge National Laboratory have found a new way to release carbon dioxide, or CO2, from a solvent used in direct air capture, or DAC, to trap this greenhouse gas. The novel approach paves the way for economically viable separation of CO2 from the atmosphere.
Amino acid sorbents (S) in water can capture carbon dioxide (CO2) directly from the air. The amine group reacts with CO2 to form a mixture of chemicals including bicarbonate (HCO3-). Researchers added a photoacid (PA) to this mixture. When the reaction chamber was exposed to light, the photoacid underwent structural changes and transferred a proton to the water. These events make the mixture more acidic and shifted its balance to produce more carbonic acid (H2CO3), which is unstable and at room temperature easily turns into CO2 and water. When the reaction chamber is covered to block the light, the photoacid returns to its initial protonated form (the trans configuration) and amino acids are now ready (deprotonated) for the next cycle of CO2 capture.
Credit
Jacquelyn DeMink/ORNL, U.S. Dept. of Energy
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