I attempted to recreate the technique described in the recent Hatton Lab paper called “Asymmetric chloride-mediated electrochemical process for CO2 removal from oceanwater”.
This attempt involved creating electrodes, setting up the equipment, and running the experiment. In this essay, I will discuss the obstacles I encountered and the lessons learned throughout the process.
Constructing the bismuth electrode was relatively straightforward. I mixed the ingredients into a paste and spread it using the doctor blade method. However, the paper did not specify the amount of solvent to use, and I likely used too little, as it resulted in a thicker paste than desired.
For the silver electrode, I tried to use the same method, as I did not have access to a specialized roller press. Unfortunately, the silver did not adhere well to the graphite paper, which posed a challenge in handling it post-drying.
I prepared the simulated seawater as described in the paper and placed it in a half-pint deli container. Then, I clipped the 1x2 cm electrodes using alligator clips and connected them to a DC power supply through the lid of the container. To measure the pH, I created an additional hole in the lid to insert a pH meter into the seawater.
I set the power supply to a maximum of 1V at 1mA and monitored the pH meter. The pH reading fluctuated initially and began to trend downward, but this only lasted for about 10 minutes before stabilizing. I attempted to push the pH further down by increasing the power, but the pH did not change significantly.
- The original experiment used 9mL of seawater, while I used approximately 400mL. I hoped the larger volume would still work but at a slower rate; however, this might not have been the case.
- Maintaining the specified 1 cm distance between the electrodes was challenging.
- To address these two issues, I plan to design a specialized 3D-printed test chamber for future experiments.
- Measuring the pH of seawater is complex. I need to study pH sensors further and apply my findings to improve the experiment in subsequent trials.
Conclusion: While I failed to get the result I wanted, the attempted provided insights that will inform version two.