New method of carbon capture works at any concentration level

Like many millennials, climate change is among the issues that I am concerned about, which makes Bela Liptak's columns on the topic particularly interesting to me. Thus, when I came across a new method of carbon capture that can take carbon out of the atmosphere, I was intrigued.

MIT postdoc Sahag Voskian and T. Alan Hatton, the Ralph Landau professor of chemical engineering, developed a method that passes air through a stack of charged electrochemical plates, according to an MIT News article titled “MIT engineers develop a new way to remove carbon dioxide from air,” by David Chandler.

Chandler explains that the device absorbs carbon dioxide as a gas stream passes over its charged electrodes, and releases the gas during discharge. “In operation, the device would simply alternate between charging and discharging, with fresh air or feed gas being blown through the system during the charging cycle, and then the pure, concentrated carbon dioxide being blow out during the discharging,” he says.

“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 called polyanthraquinone, which is composited with carbon nanotubes,” he continues. “The electrodes have a natural affinity for carbon dioxide and readily react with its molecules in the airstream or feed gas, even when it is present at very low concentrations.”

During discharge, the process is reversed, ejecting a pure stream of carbon dioxide.

Voskian describes the benefits of the binary nature of the plates’ affinity to carbon dioxide, noting that the process does not require in the input of heat or pressure differences.

“This binary affinity allows capture of carbon dioxide from any concentration, including 400 parts per million, and allows its release into any carrier stream, including 100% carbon dioxide. That is, as any gas flows through the stack of these flat electrochemical sells, during the release step the captured carbon dioxide will be carried along with it. For example, if the desired end-product is pure carbon dioxide to be used in the carbonation of beverages, then a stream of the pure gas can be blown through the plats. The captured gas is then released from the plates and joins the stream.”

In addition to requiring less energy than other systems, the team believes it will be more efficient with a long lifecycle. In lab testing, the system held up to at least 7,000 charging-discharging cycles, with an efficiency loss of 30%. However, the researchers believe they can increase to 20,000 to 50,000 cycles.

The research was recently published in the journal Energy and Environmental Science. The researcher also set up Verdox, a company that will commercialize the process. Additionally, they hope to build a pilot-scale plant soon, Chandler reports.