Scalable CO₂ Removal Using Electricity: Research Needs in Bipolar Membrane Electrodialysis

Area of Science:

• Environmental Science
• Electrochemistry
• Chemical Engineering

Background:

• Climate change necessitates innovative carbon dioxide removal technologies.
• Electrochemical direct air capture (DAC) presents a potentially transformative approach.
• pH-swing strategies enhance CO2 capture and release efficiency and scalability.

Purpose of the Study:

• To critically evaluate pH-swing electrochemical DAC approaches.
• To identify key challenges and milestones for widespread adoption.
• To highlight pathways for intensified processes and cost reduction.

Main Methods:

• Focus on bipolar membrane electrodialysis for pH-swing DAC.
• Analysis of molecular-scale requirements for bipolar membranes.
• Examination of microscale stack design for energy loss minimization.
• Consideration of system-level integration with renewable energy and advanced capture strategies.

Main Results:

• Bipolar membrane electrodialysis shows significant promise for pH-swing DAC.
• Durability and performance of ion exchange layers in bipolar membranes are critical molecular-scale challenges.
• Optimized stack designs are needed to reduce energy losses at the microscale.
• System integration requires advanced CO2 uptake formulations and reactor configurations.

Conclusions:

• Addressing molecular, micro, and system-scale challenges is essential for advancing electrochemical DAC.
• Successful development can lead to intensified processes with improved energy efficiency and reduced costs.
• Electrochemical DAC has the potential for significant CO2 removal capacities.