Researchers have been searching for a new method to combat global warming. Since a primary cause of rising temperatures is the increase in CO2emissions—which creates an increased greenhouse effect—a straightforward solution would be the removal of excess CO2from the atmosphere. A team from Ulsan National Institute of Science and Technology and Georgia Institute of Technology have developed a system capable of doing just that.
The research team was inspired by the ocean, which absorbs CO2from the atmosphere, for their design. Coined the ‘Hybrid Na-CO2System’, the device is capable of producing electricity and hydrogen energy by absorbing carbon dioxide.
The system works similarly to a liquid battery, relying on two liquids, an aqueous (water-based) solution, and an organic electrolyte (a substance that allows the flow of an electrical charge). The two are separated by a sodium super ionic conductor, or NASICON, membrane: a structure containing channels which allow the passage of sodium. This allows the electrolyte—in this case, sodium—to flow into the aqueous solution and separate. A positively charged sodium metal conductor (anode) is placed into the organic electrolyte while a negatively charged conductor (cathode) is placed in the aqueous solution.
The cathode and anode are attached to an electrical circuit that creates a chemical reaction and stimulates the flow of electrons. When CO2is added to the aqueous electrolyte, it dissolves and reacts with the cathode. This reaction causes the solution to become more acidic, creating electricity and hydrogen energy.
While the concept seems promising, is it a viable answer to the issue of atmospheric CO2?
During testing, the researchers discovered that their system was able to convert almost 50% of the carbon dioxide absorbed into energy. The other half recovered from the electrolyte turned into baking soda. Data also shows the system was able to run smoothly for over 1,000 hours without damaging the conductors.
When compared to similar devices, the Hybrid Na-CO2does not emit any forms of carbon dioxide. However, the device does have its own issues. In their study, published in the journal iScience, researchers acknowledge that “the discharge reaction of hybrid Na-CO2cell is relatively slow because of the low conductivity of the ceramic NASICON electrolyte.”
The researchers also expressed concern with the use of sodium metal, which is highly reactive when exposed to water or air and can be harmful to humans. Additionally, the Hybrid Na-CO2System is an expensive solution. However, the team is dedicated to improving the components of their device, which seems to be aneffective tool for the future.
For many years, the main strategy to reduce global warming was to decrease fossil fuel use. Now, however, that may not be enough. The world’s governments aimed to cap the temperature rise at 2°Celsius, and the only way to accomplish that is by removing CO2from the atmosphere. Studies estimate that carbon emissions rose by 2.7% in 2018.
While carbon dioxide capture systemsmay not be enough to neutralize the threat of global warming entirely, innovations such as these make that goal more reachable.