Intermission

Climate change mitigation necessitates the development of effective carbon capture technologies, which include separation and concentration of CO₂. Today's maturing thermochemical technologies have exceedingly high energy requirements and rigid form factors that restrict their versatility. Using renewable electricity, rather than heat, as the energy input to drive CO₂ separation and concentration provides a compelling alternative to surpass these limitations. A wide range of electrochemical processes were recently developed for carbon capture from various sources, including high concentration streams such as power plant flue gas and dilute streams like air and seawater [1, 2]. Electrochemical carbon capture (ECC) processes rely on redox reactions to desorb CO₂ through an electro-swing mechanism. Due to this unique desorption mechanism, ECCs offer several advantages, including lower energy requirements, eliminating the need to operate at elevated temperatures, and minimizing the rate of absorbent degradation [1, 3]. Additionally, ECCs offer the inherent advantages of electrochemical systems, such as modularity, scalability, and ease of retrofitting. In this presentation, I describe the emerging science and research progress underlying ECC processes and assess their current maturity and trajectory for carbon capture from various sources. An electrochemically mediated amine regeneration process [4] and a pH-mediated method, inspired by vanadium redox flow batteries [5], will be discussed in further detail. These systems have demonstrated efficient and continuous CO₂ separation from various sources, paving the way for sustainable carbon capture technologies.

[1] Rahimi M, Khurram A, Hatton TA, Gallant B. Electrochemical carbon capture processes for mitigation of CO₂ emissions. Chemical Society Reviews. 2022;51:8676-95.

[2] Aleta P, Refaie A, Afshari M, Hassan A, Rahimi M. Direct ocean capture: the emergence of electrochemical processes for oceanic carbon removal. Energy & Environmental Science. 2023;16(11):4944-67.

[3] Rahimi M, Diederichsen KM, Ozbek N, Wang M, Choi W, Hatton TA. An electrochemically mediated amine regeneration process with a mixed absorbent for postcombustion CO₂ capture. Environmental Science & Technology. 2020;54:8999-9007.

[4] Hassan A, Refaie A, Aleta P, Afshari M, Kalantari E, Fang Y, Rahimi MM. Reviving the absorbent chemistry of electrochemically mediated amine regeneration for improved point source carbon capture. Chemical Engineering Journal. 2024 Mar 15;484:149566.

[5] Afshari M, Refaie A, Aleta P, Hassan A, Rahimi M M. A Vanadium Redox Flow Process for Carbon Capture and Energy Storage. Archived May 2024.