2026-04-14 マサチューセッツ工科大学（MIT）
＜関連情報＞
- https://news.mit.edu/2026/carbon-removal-project-supports-maines-blue-economy-broader-marine-health-0414
- https://pubs.acs.org/doi/10.1021/acs.est.4c05721#Abstract
- https://pubs.rsc.org/en/Content/ArticleLanding/2023/EE/D2EE03804H
電気化学的海洋無機炭素除去の熱力学 Thermodynamics of Electrochemical Marine Inorganic Carbon Removal
Fabian J. Dickhardt, Michael P. Nitzsche, Simon Rufer, T. Alan Hatton, and Kripa K. Varanasi
Environmental Science & Technology Published: December 18, 2024
DOI:https://doi.org/10.1021/acs.est.4c05721
Abstract
In recent years, marine carbon removal technologies have gained attention as a means of reducing greenhouse gas concentrations. One family of these technologies is electrochemical systems, which employ Faradaic reactions to drive alkalinity-swings and enable dissolved inorganic carbon (DIC) removal as gaseous CO2 or as solid minerals. In this work, we develop a thermodynamic framework to estimate upper bounds on performance for Faradaic DIC removal systems. To assess the fundamental mass balances of these systems, we first define unit operations in the DIC/total alkalinity (TA) space. By coupling a seawater speciation model to an electrochemical framework, we provide a generalized comparison of gas evolution and mineralization DIC removal routes, focusing on asymmetric charge/discharge systems. We then show how this framework can be extended to other processes, such as those employing dilution schemes. Finally, we provide a minimum energetic assessment of mCDR pathways relative to direct air capture. Overall, this thermodynamic framework aims to guide system and process design and to drive material discovery and engineering for future electrochemical marine DIC removal systems.
海水からのCO2除去の ための非対称塩化物媒介電気化学プロセス Asymmetric chloride-mediated electrochemical process for CO2 removal from oceanwater
Seoni Kim,Michael P. Nitzsche,Simon B. Rufer,Jack R. Lake,Kripa K. Varanasi and T. Alan Hatton
Energy and Environmental Science Published:13 Feb 2023
DOI:https://doi.org/10.1039/D2EE03804H
Abstract
In recent years, the ocean has come to be recognized as a global-scale reservoir for atmospheric CO2. The removal of CO2 from oceanwater is thus considered a compelling approach to reduce ambient CO2 concentrations, and potentially achieve net-negative emissions. As an effective means of oceanic CO2 capture, we report an asymmetric electrochemical system employing bismuth and silver electrodes that can capture and release chloride ions by faradaic reactions upon application of appropriate cell voltages. The difference in reaction stoichiometry between the two electrodes enables an electrochemical system architecture for a chloride-mediated electrochemical pH swing, which can be leveraged for effective removal of CO2 from oceanwater without costly bipolar membranes. With two silver–bismuth systems operating in tandem in a cyclic process, one acidifying the ocean water, and the other regenerating the electrodes through alkalization of the treated stream, CO2 can be continuously removed from simulated oceanwater with a relatively low energy consumption of 122 kJ mol−1, and high electron efficiency.
