“We hope this new method will reduce the price of oceanic carbon capture by reducing the energy usage, taking advantage of variable electricity pricing throughout the day, and increasing the stability of the system.” ~ Rachel Silcox, Mechanical Engineering doctoral candidate, member of Prof. Rohini Bala Chandran’s TREE lab
The work of the TREE Lab, led by Prof. Rohini Bala Chandran, Global CO2 Initiative Faculty Affiliate, is featured in this issue. The TREE lab recently received approval for their patent for taking CO2 out of seawater and has a publication, “Demand-side Flexibility Enables Cost Savings in a Reversible pH-Swing Electrochemical Process for Oceanic CO2 Removal,” coming out soon in Cell Reports Physical Science.
Who are the people in the lab working on this problem?
The TREE Lab, led by Rohini, began working on CO₂ capture from ocean water in 2021. Rachel Silcox, Ph.D. Candidate, Mechanical Engineering, has spearheaded this work with funding from the NSF Graduate Research Fellowship, Graham Sustainability through the Carbon Neutrality Acceleration Program, and Rohini’s startup funds.
Contributors to upcoming work include Mechanical Engineering undergraduate students Tavi Kipnis, Declan Crowley, and Nicole France, and Master’s student Fernando Villavicencio.
Can you explain the lab’s work pertaining to taking CO₂ out of water?
We remove CO₂ from ocean water by cyclically shifting the pH. By lowering the pH, dissolved bicarbonate ions already present in ocean water shift into the form of dissolved CO₂ molecules. We can then strip the CO₂ gas from its dissolved state in water. Then we increase the pH of the water back to neutral following the CO₂ extraction to make sure it is safe to release back to the ocean. This process is similar to how a baking soda volcano works. Adding acid to the solution reacts with the bicarbonate ions to produce gaseous CO₂ that we can then capture.
