PNNL

Abstract

Carbon dioxide (CO2) capture from seawater is a viable, long-term solution for addressing legacy carbon pollution on the planet. However, significant challenges to widespread applicability exist in terms of efficiency, cost, and scalability. In this work, we have developed an electrochemical hydrogen-looping system that capitalizes on the generation of the proton and OH- from seawater. The system can be used to capture CO2 at a much lower low energy cost (i.e., at a theoretical cell voltage at 0.48V). We have demonstrated that the electrochemical hydrogen-looping flow cell can remove CO2 from simulated seawater at a record low electric energy consumption of 660 kWh ton-1 CO2, which is a significant reduction of 56% compared with the currently used bipolar membrane electrodialysis technology. The electrochemical hydrogen looping-flow cell with its much lower energy consumption provides an economical approach for direct removal of CO2 from seawater at practical scale.