Carbon capture via electrochemically mediated alkaline absorption: Lab-scale continuous operation

Energy-efficient capture technologies need to be deployed by 2050 to abate global warming caused by excessive carbon dioxide (CO₂) emissions. CO₂ capture using alkaline solutions and absorbent regeneration mediated through bipolar membrane electrodialysis (BMED) have been tested previously as a standalone technology. However, the continuous operation of an integrated system remains largely unclear. Here, a bench-scale study was conducted using an integrated prototype to analyze the performance of CO₂ capture and electrochemical regeneration using potassium hydroxide (KOH) aqueous solution. A wide range of current densities from 150 to 1000 A/m² was applied to demonstrate the continuous operation of the CO₂ capture system emphasizing the stability in attainable high rich carbon loading and CO₂ desorption. The electrochemical regeneration module achieved CO₂ desorption efficiency of 70% and absorbent recovery up to 89% under industrial relevant current densities of 500–1000 A/m². The absorbent recovery has been identified to be a result of the combined effect of load ratio and rich carbon loading. The observed inefficient CO₂ separation indicates significant potential to enhance energy efficiency. These results represent a pivotal step forward in electrochemically mediated CO₂ capture technology, with promising potential for rapid industrial scale-up in the near future.