New Compound Efficiently Captures Carbon Dioxide From the Atmosphere

A new method to capture carbon dioxide from the air has been developed at the University of Helsinki's chemistry department.

The method developed by Postdoctoral Researcher Zahra Eshaghi Gorji is based on a compound of superbase and alcohol. Tests done in professor Timo Repo’s group show that the compound appears promising: one gram of the compound can absorb 156 milligrams of carbon dioxide directly from untreated ambient air. However, the compound does not react with nitrogen, oxygen or other atmospheric gases. Capacity clearly outperforms the CO₂ capture methods currently in use.

The CO₂ captured by the compound can be released by heating the compound at 70 °C in 30 minutes. Clean CO₂ is recovered and can be recycled.

The ease of releasing CO₂ is the key advantage of the new compound. In current compounds, releasing CO₂ typically requires heat above 900 degrees Celsius. 

In addition, the compound can be used multiple times: the compound retained 75 percent of its original capacity after 50 cycles, and 50 percent after 100 cycles.

Non-toxic and cost-effective

The new compound was discovered by experimenting with a number of bases in different compounds, says Eshagi Gorji. The experiments lasted more than a year in total.

The most promising base proved to be 1,5,7-triazabicyclo [4.3.0] non-6-ene (TBN), developed at in the professor Ilkka Kilpeläinen’s group, which was combined with benzyl alcohol to produce the final compound.

None of the components is expensive to produce, Eshaghi Gorji points out. In addition, the fluid is non-toxic.

The compound will now be tested in pilot plants at a near-industrial scale, rather than in grams. A solid version of the liquid compound must be made for this purpose.

The idea is to bind the compound to compounds such as silica and graphene oxide, which promotes the interaction with carbon dioxide.

Reference: Eshaghi Gorji Z, Singh B, Lempinen A, Repo T. Direct air capture: recyclability and exceptional CO2 uptake using a superbase. Environ Sci Technol. 2025;59(49):26506-26513. doi: 10.1021/acs.est.5c13908 

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