Integrated Bipolar Membrane Electrodialysis and Electrolysis for CO2 Capture and Conversion

Decarbonization of seawater using carbon capture and conversion technologies remain a significant process engineering challenge. Here, we present an integrated system for combined CO2 capture and conversion, which couples bipolar membrane electrodialysis (BMED) with a CO2 electrolyzer (CO2E) in a single system (BMEED). CO2desorption is demonstrated from bicarbonate-based carbon capture absorbents with a specific energy consumption of 3.90 kWh/kg-CO_2. Integrated BMEED achieved a CO_2 to CO conversion selectivity of 98% and specific energy consumption of 34.00 kWh/kg-CO. By comparison, two independent subsystems exhibit 98% selectivity and 39.22 kWh/kg-CO which is 17% higher. Techno-economic analyses reveal BMEED reduced the levelized cost of CO production by 42% compared to the stand-alone carbon capture and conversion subsystems. Integration shifts CO production from a non-profitable baseline to a profitable scenario of \$193/ton-CO. BMEED demonstrates the advantages of process intensification for CO_2 capture and conversion and establishes a promising, energy-efficient electrochemical pathway.