A new direct air capture (DAC) carbon capture technology being developed by researchers at Tokyo Metropolitan University is claimed to be 99% efficient at removing the harmful gas from the atmosphere when at low concentrations.

As the global energy market continues to advance development of sustainable alternatives to help reduce atmospheric carbon dioxide (CO2), carbon capture is being seen as an essential component of lowering emissions. 

Using a liquid system, direct air capture (DAC) passes air through a chemical solution to remove CO2 before applying high temperatures to the reintegrate the chemicals back into the process. 

Solid DAC technology uses sorbent filters to chemically bind the CO2 before being heated, placed under a vacuum, and releasing the CO2, which can then be either stored or used. 

Source: Tokyo Metropolitan University

The new highly efficient method uses a compound called isophorone diamine (IPDA) in a liquid-solid phase separation system to remove CO2 at low concentrations contained in the atmosphere with 99% efficiency. 

Tests conducted during the research showed that the IPDA can remove more than 99% of CO2 from the air with a concentration of 400 parts per million (ppm). 

The solid dispersed in solution also required heating to a lower temperature than other solutions. At 333 K (60 celsius) the captured CO2 can be released, recovering the original liquid. 

With the ability to remove low atmospheric concentrations of CO2 (400ppm) at least twice as fast as existing solutions (such as monoethanolamine), the technology is the fastest in the world for its designated purpose. 

Having completed its initial research, the team can now look at how the technology may be applied to current industrial applications.