A Bench-Scale Demonstration of Direct Air Capture Using an Enhanced Electrochemical System

The bench-scale demonstration of the UKy-IDEA process for direct air capture (DAC) technology combines solvent-aided CO2 capture with electrochemical regeneration (ER) through a pH swing process, enabling efficient CO2 capture and simultaneous solvent regeneration, producing high-purity hydrogen as a valuable co-product. The system shows stable performance with over 90% CO2 capture efficiency and approximately 80% CO2 recovery, handling ambient air at 280 L/min. During testing, the unit captured 1 kg of CO2 over 100 h, with a concentrated CO2 output purity of around 70%. Operating efficiently at low voltage (<3 V), the system supports flexible and remote operation without AC/DC converters when using intermittent renewable energy. Techno-economic analysis (TEA) and Life Cycle Assessment (LCA) highlight its minimized required footprint and cost-effectiveness. Marketable hydrogen offsets capture costs, and compatibility with renewable DC power enhances appeal. Hydrogen production displacing CO2 produced via electrolysis achieves 0.94 kg CO2 abated per kg CO2 captured. The project would be economic, with USD 26 per ton of CO2 from the federal 45Q tax credit for carbon utilization, and USD 5 to USD 12 per kg for H2.