CO2-Selective Absorbents in Air: Reverse Lipid Bilayer Structure Forming Neutral Carbamic Acid in Water without Hydration

Waterproof chemical clears the air

23 November 2017

A chemical that absorbs carbon dioxide but repels water could improve the efficiency of carbon capture and storage.

Removing carbon dioxide (CO₂) from the air can help reduce air pollution, but current methods absorb water vapour, which must be burned off before CO₂ can be stored, making the process energy intensive. To address this, researchers from Kanazawa University added water-repellent molecules to a range of CO₂ absorbing compounds of benzene-containing amines. They placed a portion of the best performing chemicals on scales in open air for two weeks and weighed them regularly to determine the amounts of water and CO₂ absorbed.

The team found that chemicals made from xylylenediamines absorbed CO₂ but not water, with meta-xylylenediamine (MXDA) absorbing the fastest. The researchers then dissolved the MXDA-CO₂ product in water and exposed the solution to air, which left a residual white solid containing no water. Heating the solid to 120°C released dry CO₂, which can be stored without further dehydration.

If they work on an industrial scale, waterproof CO₂ absorbents could reduce energy used by carbon capture and release projects.

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References

1. Journal of the American Chemical Society 139, 4639–4642 (2017). doi: 10.1021/jacs.7b01049