Engineers at the Massachusetts Institute of Technology (MIT) have developed a new way of removing carbon dioxide (CO2) atmosphere.

The carbon capture device is essentially a large, specialised battery which absorbs CO2 from the air passing over its electrodes as it is being charged up, and then releasees the gas as it is being discharged.

When in use, the device alternates between charging and discharging, with fresh air or feed gas being blown through the system during the charging cycle, and then the pure, concentrated CO2 being blown out during the discharging.

As the battery charges, an electrochemical reaction takes place at the surface of each of a stack of electrodes. These are coated with a compound call polyanthraquinone, which is composited with carbon nanotubes.

The reserve reaction takes place when the battery is discharged – during which the device can provide part of the power needed for the whole system – and in the process ejects a stream of pure CO2.

“The greatest advantage of this technology other most other carbon capture or carbon absorbing technologies is the binary nature of the adsorbent’s affinity to carbon dioxide,” said Sahag Voskian, MIT Postdoc.

“The binary affinity allows capture of carbon dioxide from any concentration, including 400 plants per million, and allows its release into any carrier stream, including 100% CO2.” 

“This carbon dioxide technology is a clear demonstration of the power of electrochemical approaches that require only small swings in voltage to drive the separations.” 

The researchers have set up a company called Verdox to commercialise the process and hope to develop a pilot-scale plant within the next few years.

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