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Capturing Carbon Dioxide With Much Less Energy

September 5, 2023 | Leave a Comment

Currently when CO2 is trapped before it escapes into the atmosphere, the process requires a large amount of energy and equipment. Now MIT researchers have designed a capture system using an electrochemical cell that can easily grab and release CO2. The device operates at room temperature and requires less energy than conventional, amine-based carbon-capture systems.

The researchers reported in ACS Central Science that the design is a capture system using an electrochemical cell that can easily grab and release CO2. The device operates at room temperature and requires less energy than conventional, amine-based carbon-capture systems.

Many industries are turning to electrification to help curb carbon emissions, but this technique isn’t feasible for all sectors. For example, CO2 is a natural byproduct of cement manufacture, and thus a major contributor to emissions on its own. Excess gas can be trapped with carbon-capture technologies, which typically rely on amines to help “scrub” the pollutant by chemically bonding to it. But this also requires lots of energy, heat and industrial equipment – which can burn even more fossil fuels in the process. Carbon capture could itself be electrified by using electrochemical cells, and these devices could be powered by renewable energy sources.

Electrochemical cation-swing process that is able to reversibly modulate the CO2 loading on liquid amine sorbents in dimethyl sulfoxide (DMSO) solvent. Image Credit: ACS Publications. Click the study paper link for more images and information.

So, Fang-Yu Kuo, Sung Eun Jerng and Betar Gallant wanted to develop an electrochemical cell that could easily and reversibly trap CO2 with minimal energy input.

The team first developed an electrochemical cell that could both catch and release emitted carbon by “swinging” positively charged cations across a liquid amine dissolved in dimethyl sulfoxide. When the cell was discharged, a strong Lewis cation interacted with the carbamic acid, releasing CO2 and forming the carbamate amine. When the process was reversed and the cell charged, the cation was removed, and the cell could capture CO2 and reform the carbamic acid in the process.

The researchers optimized the ion-swinging process with a combination of potassium and zinc ions. In a prototype cell, they used these two ions as the basis for the cell’s cathode and anode. This cell required less energy than other, heat-based cells and was competitive with other electrochemical cells in initial experiments. Additionally, they tested the device’s long-term stability and found that nearly 95% of its original capacity was maintained after several cycles of charging and discharging, demonstrating that the system was feasible. The researchers say that this work shows that an electrochemical alternative is possible and could help make continuous CO2 capture-release technologies more practical for industrial applications.

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This is the kind of innovative insight that makes the idea of recycling CO2 look more and more practical. Each of these incremental steps are adding up to a more firm basis to think that producing CO2 sourced fuels from effluents as a real possibility.

One day perhaps the hysterics of carbon will recede. After all, humans are carbon powered critters as well as about everything we need. We simply can’t live without it after all.


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