Is there a simple and economical solution to capture CO2 in the air?

Group of researchers working in a laboratory.

An international team of researchers, including Phillip Milner, assistant professor of chemistry in the College of Arts & Sciences at Cornell University, and Alexander Forse of the University of Cambridge, has developed a revolutionary method for capturing carbon dioxide (CO2) directly from the air.

A pioneering method

Scientists have succeeded in transform activated carbon, in one powerful CO2 absorber. This coal,Featuring exceptional adsorption properties, now effectively retains CO2 from ambient air thanks to the addition of ions.

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The researchers discovered that activated carbon could capture CO2 when charged with ions forming reversible bonds with carbon dioxide. This charged “sponge carbon” is not only more efficient, but also more energy efficient than current carbon capture methodswhich often require high temperatures of up to 900°C, and the use of natural gas.

Preparation of charged carbons: A porous carbon electrode is charged into an electrochemical cell (step 1). The electrodes are then removed from the cell, washed with deionized water, and evacuated to remove solvent molecules (shown as green circles) to obtain charged sorbents (step 2). The activated carbon diagram is adapted from reference 33, Springer Nature America. — **Preparation of charged coals** : A porous carbon electrode is loaded into an electrochemical cell (step 1). The electrodes are then removed from the cell, washed with deionized water, and evacuated to remove solvent molecules (shown as green circles) to obtain charged sorbents (step 2). The activated carbon diagram is adapted from reference 33, Springer Nature America.

Promising results

The results are very encouraging. The study published on June 5 in the journal Nature reveals that this charged material requires much lower temperatureses, between 90 and 100°C, to release the captured CO2. Therefore, the storage becomes possible, because these temperatures can be achieved through the use of renewable electricity. This resistive heating method, which heats the material from the inside, speeds up the process while reducing energy consumption.

Tests have shown that the Charged activated carbon can effectively capture CO2 directly from the air through the hydroxide binding mechanism. This method does not require the use of natural gas, further reducing its carbon footprint.

Activated carbon, commonly used for water purification, now has an innovative ability to capture and retain CO2 from the air.

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Using this process, researchers impregnated inexpensive activated carbon fabric with hydroxide ions. This tissue, functioning like a battery electrode, accumulates ions in its tiny pores. Once loaded, the coal is removed, washed and dried. Tests have demonstrated that this modified activated carbon can effectively capture CO2 directly from the air thanks to the hydroxide binding mechanism.

A response to the climate emergency

Capturing carbon emissions from the atmosphere is a solution of last resort, but given the climate emergency, it is an avenue worth exploring, explains Alexander Forse, who led the research.

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Reducing carbon emissions is paramount, but removing greenhouse gases (GHGs) is also crucial to achieving net-zero emissions and limit the most serious effects of climate change. It is therefore essential to maximize our efforts on all possible fronts.

Towards diversified applications

Although this technology is still in development, it opens the way to applications well beyond CO2 capture. The pores of the carbon and the inserted ions can be adjusted to capture a variety of molecules. This flexibility could revolutionize everything from purifying air and water to recovering valuable resources.

However, challenges remain. Researchers are currently working on improve the CO2 capture capacity of materials, particularly in humid conditions where efficiency is reduced.

The optimization ofe these materials is essential to maximize their industrial utility.

Reference : Li, H., Zick, ME, Trisukhon, T., Signorile, M., Liu, X., Eastmond, H., Sharma, S., Spreng, TL, Taylor, J., Gittins, JW, Farrow, C., Lim, SA, Crocellà, V., Milner, PJ, & Forse, AC (2023). Capturing carbon dioxide from air with charged-sorbents. Nature.