Direct air capture (DAC) of carbon dioxide is considered a key tool in limiting global warming. However, large-scale deployment has been hindered by high energy demand. In existing systems, sorbent regeneration often requires temperatures of up to 900°C.
Researchers from the University of Helsinki have introduced a chemical solution that dramatically lowers this barrier. The study was published in Environmental Science & Technology.
Chemical foundation of the new sorbent
The method is based on a two-component liquid system combining benzyl alcohol and a strong organic base known as 1,5,7-triazabicyclo[4.3.0]non-6-ene (TBN). The mixture selectively binds CO₂ molecules while ignoring nitrogen and oxygen in the air.
Laboratory tests showed that one gram of the compound absorbed up to 156 mg of CO₂ directly from ambient air.
Key advantage — regeneration at 70°C
The major breakthrough lies in the regeneration process. Releasing the captured CO₂ requires heating the material to only 70°C for 30 minutes. This enables the use of low-grade heat sources such as industrial waste heat, data centers, or simple solar collectors.
Limitations and ongoing development
The main drawback is material stability. After 50 absorption–regeneration cycles, the sorbent retains about 75% of its original capacity, dropping to 50% after 100 cycles. This degradation rate is currently too high for industrial-scale operation.
Another development focus is converting the liquid sorbent into a solid material. Researchers plan to anchor TBN molecules onto porous substrates such as silica or graphene oxide to create practical filter systems.
Environmental safety and scaling potential
The compound’s components are widely available, relatively inexpensive, and non-toxic. The next phase involves building a pilot system operating with kilograms of material under real-world conditions.
If durability issues can be resolved, this low-temperature carbon capture technology could become a foundation for scalable air purification systems integrated into urban and industrial infrastructure.