MIT Engineers Develop a New Way to Remove Carbon Dioxide from Air

The process could work on any concentration, from power plant emissions to open air.

Diagram of the new system, developed by MIT engineers to filter carbon dioxide from a stream of air and store it for later use or disposal. ( Image courtesy of the researchers.)

Diagram of the new system, developed by MIT engineers to filter carbon dioxide from a stream of air and store it for later use or disposal. ( Image courtesy of the researchers.)

Scientists define problems, engineers solve them, and journeymen transform those solutions into functional systems. Nowhere has that process been more evident than in the search for climate change solutions over the last two decades.

However, recently, a group of scientists and engineers at MIT have developed a novel device that would be useful even if climate change was not an issue.

The device is essentially a battery that absorbs CO2 from a stream of air passing over its electrodes as it is charging and then passes the CO2 into a storage tank during its discharge phase. The negative electrode is coated with a polymer known as polyanthraquinone that is composited with carbon nanotubes. This material readily reacts with CO2 molecules even when the gas is only present in small amounts.

The great advantage of this system over other carbon capture methods is the binary nature of the electrode material, which shows a great affinity for CO2 when it is charging and no affinity at all while discharging. This binary nature means that no chemical processing or additional energy is required to remove the gas from the collection plates during the discharge phase.

In the lab, researchers have proven the system can withstand 7,000 charging and recharging cycles with only a 30 percent loss of efficiency over that period and estimate the practical life cycle could be improved to as many as 50,000 cycles. The electrodes can be inexpensively produced using existing manufacturing techniques.

Compared to other current carbon capture techniques, the system is very energy efficient, consuming only about one gigajoule of energy per ton of carbon captured. Other methods may consume as much as 10 gigajoules depending on the inlet concentration of CO2.

Carbon dioxide has a wide range of industrial, agricultural, chemical and pharmaceutical applications. When commercially available, this device could find immediate use in the production of methanol, inorganic and organic carbonates, and plastics. Carbon dioxide is also used in refrigeration systems, welding systems, water treatment processes, and carbonated beverages.

CO2 can also be converted into carbon monoxide and combined with hydrogen to make gasoline. Imagine that, MIT engineers have designed a device that rewards people for fighting climate change by removing CO2 from the atmosphere.

You can read the paper submitted by MIT to the Energy and Environmental Science Journal here.