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Electrochemically Modulated CO 2 Removal from Oceanwaters

2022; Institute of Physics; Volume: MA2022-02; Issue: 27 Linguagem: Inglês

10.1149/ma2022-02271039mtgabs

2152-8365

Seoni Kim, Simon Rufer, Jack Lake, Michael P. Nitzsche, Jin Soo Kang, Kripa K. Varanasi, T. Alan Hatton,

Fuel Cells and Related Materials

As the concentration of carbon dioxide is continuously increasing, there have been a lot of efforts to remove CO 2 from various sources. While most of the attention has been focused on CO 2 capture at point sources followed by geological storage, interest in negative emission strategies also increased recently. One of the promising approaches for negative emissions is removing CO 2 from ocean water. The world ocean is the largest carbon sink, containing 120 times higher concentration compared to the atmosphere. Therefore, by removing CO 2 from ocean water, we can expect a reduction in CO 2 concentration in the atmosphere. Considering that the CO 2 -reduced oceanwater should be returned to the ocean, the addition of chemicals, and the formation of undesirable compounds should be avoided. In this respect, the electrochemical approach can be a good choice because it does not require additional chemicals, and the control of voltage can tune the reactions in the system. Until now, several approaches have been made by using the electrodialysis process. However, the use of bipolar membrane for water dissociation makes this process expensive, making the application of this process sluggish. In this talk, we will present a new membrane-free approach based on electrochemical modulation of the pH to release the CO 2 from ocean water. After removing CO 2 , the treated water is alkalized before being returned to the ocean. Using an electrochemical pH swing approach, we could successfully remove the CO 2 from ocean water without employing expensive membrane or additional chemicals.