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This invention introduces a new cell design to extract CO2 from seawater without harming the ocean’s natural balance. It uses a special electrochemical cell made up of three chambers to separate and treat seawater, freeing up CO2 while ensuring there is a minimal pH change to the water before it's returned to the ocean. The invention here modifies an existing cell design to enhance the mass transfer within the center chamber to allow the technology to be scaled-up to industrially relevant technology readiness levels. This process helps the ocean absorb even more CO2 from the atmosphere, which can aid in fighting climate change.

Description

The system works by running an electric current through seawater in a special three-chamber electrochemical cell. In one chamber, the anode, hydrogen is consumed as it is split into protons, which then traverse a membrane into the central chamber, where seawater is present. The addition of the protons into the seawater decreases its pH and shift the dissolved carbon from bicarbonate, which is very stable, to dissolved CO2. Sodium ions then traverse a second membrane into the cathode chamber where water is split, forming OH- anions and increasing its pH, while producing gaseous H2, which is then looped around to the anode compartment. While this electrochemical chamber had been previously demonstrated, it was done on a small scale. In this invention, the design of the middle chamber was modified to enhance the mass transfer between the anode and cathode chambers, which will minimize system inefficiencies as the system is brought up to full scale. After the dissolved CO2 is removed from low pH water from the central compartment, it is combined with the elevated pH water from the cathode to neutralize any net pH change, meaning it won’t negatively affect the ocean’s pH when returned. The design of the system has been improved to work on a larger scale, making the process more efficient and effective at capturing CO2.

Benefits

• Scalable: This technology can be expanded from small tests to larger, more powerful systems for wider use.
• Lower energy use: It uses less energy compared to other methods, making the process more affordable.
• Eco-friendly: It ensures the seawater’s pH is neutralized, protecting the ocean environment.
• More efficient: The system is designed to speed up the process of releasing CO2 and processing the water, making it more effective.

Applications and Industries

• Carbon capture: This technology can be used to remove CO2 from seawater, helping the ocean absorb more CO2.
• Desalination plants: Since desalination plants already use large amounts of seawater, this system could be added to help capture CO2 while providing clean water.
• Environmental research and innovation: Research labs and companies developing new climate technologies could use this system to improve their methods of carbon capture and ocean protection.

Contact

• To learn more about this technology, email partnerships@ornl.gov or call 865-574-1051.