Hidden Acidification Challenges in Electrochemical Ocean Decarbonization

Electrochemical direct ocean capture (eDOC) is an emerging methodology for carbon capture. However, our comprehensive thermodynamic and initial kinetic analyses reveal critical challenges inherent in the electrochemical pH-swing process. Specifically, the mixture of treated ocean water post-eDOC fails to achieve complete neutralization, resulting in unintended ocean acidification. This issue stems from the disproportionate impacts of acidification and alkalinization on dissolved inorganic carbon dynamics and hydroxide precipitation. Our findings underscore the necessity for innovative process designs that effectively balance pH shifts and manage precipitate formation, thereby ensuring the environmental sustainability of eDOC technologies.