Teresa Madaleno

Large-scale capturing of carbon dioxide is considered necessary by many environmental experts, if we want to limit the rise of global temperature. Of course, grabbing billions of tons of CO2 is a tall task but chemists at the Department of Energy in the United States believe they are closer to knowing how to do it.

As outlined on the newswire service, Newswise, a team of experts at the lab mixed amino acids with water to make an aqueous sorbent with the ability to grab carbon dioxide from the air. They then put the sorbent in a humidifier to maximize contact between air and the sorbent, which sped up carbon uptake. Once the carbon was absorbed into liquid, it formed a bicarbonate salt.

Two members of the study designed and synthesized an organic compound that contained guanidines, which are chemical groups in proteins that are able to bind negatively charged ions. The guanidine was added to the amino acid sorbent solution containing bicarbonate and this created an insoluble carbonate salt that regenerated the amino acid sorbent, which could be recycled. Part of the study involved a thermodynamic analysis to help determine how much energy was actually required to reach each chemical reaction.

In order to make the process energy-sustainable, concentrated solar power was used. In fact, a solar-powered oven like those used to cook foods. In this case, a parabolic mirror to concentrate the sun’s rays was employed. After placing the guanidine carbonate crystals on a tray inside the solar oven, the CO2 was liberated in just two minutes, in a system regenerating guanidine for recycling.

So what does all of this really mean? Well, if you are a science-enthusiast you will appreciate that this process is preferable because you want to avoid producing more CO2 while you are trying to capture it. To those less science focused, the important point here is that if applied on a large scale this experiment, along with geologic storage, could increase action against global warming.

The chemists are continuing their work with the goal of finding a way to design a more efficient guanidine-based sorbent and gain a better understanding of the structural and thermodynamic aspects of direct air capture.