CO2 separation using bipolar membrane electrodialysis

Abstract

Caustic solvents such as sodium or potassium hydroxides, converted viaCO₂ capture to aqueous carbonates or bicarbonates, are a likely candidate for atmospheric CO₂ separation. We have performed a comprehensive experimental investigation of CO₂ gas regeneration from aqueous potassium carbonate and bicarbonate solutions using bipolar membrane electrodialysis (BPMED). This system allows the regeneration of pure CO₂ gas, suitable for subsequent sequestration or reaction to synthetic hydrocarbons and their products, from aqueous carbonate/bicarbonate solutions. Our results indicate that the energy consumption required to regenerate CO₂ gas from aqueous bicarbonate (carbonate) solutions using this method can be as low as 100 kJ (200 kJ) per mol of CO₂ in the small-current-density limit.