A new, efficient way to capture CO₂ from the air

Diagram of the new system (MIT News)

The Massachusetts Institute of Technology (MIT) engineers have developed a new way to remove carbon dioxide (CO₂) from the air without large heat losses. The method can use any concentration of CO₂ in a stream of gas: from that of the atmosphere/air to high concentrations emitted from power plants.

The method passes gas through a stack of electrochemical plates (like a battery). The plates alternate between being charged and discharged. When air (or other gas stream) pass over the plates they are charged up and remove CO₂ from the gas stream. When the discharging cycle begins a pure stream of CO₂ is then released. Also during the discharge power is provided to drive the whole system. The cycle operates at room temperature and normal air pressure.

The air leaving the device has much less of the greenhouse gas. The resulting pure stream of CO₂ captured can be used productively to make fizzy drinks or assist with plant growth in greenhouses. Both these two industries currently use fossil fuels to make the CO₂ they need. The gas could also be compressed and injected underground for long-term disposal or, alternatively, it could be used to make fuels through a series of chemical and electrochemical processes.

Further information:
- MIT engineers develop a new way to remove carbon dioxide from the air (includes video). MIT News, October 24, 2019.
- A new paper in the journal Energy and Environmental Science by Sahag Voskian and T. Alan Hatton entitled “Faradaic electro-swing reactive adsorption for CO₂ capture.”