CO2 concentration using bipolar membrane electrodialysis

The ability to efficiently capture carbon dioxide (CO2) from the atmosphere would be a transformational technology, enabling the capture of CO2 for use in carbon-neutral liquid fuels [1] as well as the possibility to directly reduce the atmospheric CO2 concentration via capture and sequestration. Capture and concentration of CO2 from dilute sources such as the atmosphere will likely use carbonate or bicarbonate capture solutions [2]. We present new experimental results of CO2 concentration from potassium carbonate and bicarbonate solutions using bipolar membrane electrodialysis. By carefully monitoring the pH, CO2 transport, current, and voltage during the experiment, we determine the rate and energy consumption of CO2 transport. We also discuss progress toward high-pressure electrodialysis [3] for improved performance and reliability. [1] Karl Littau et al., "An 'Atmospherically Healthy' Recipe for Carbon-Neutral Fuels: A synthetic fuel made from sunlight, CO2, and water," CTSI Clean Technology & Sustainable Industries Conference & Trade Show, Boston, MA, June 1-5, 2008. [2] M.D. Eisaman et al., "Energy-efficient electrochemical CO2 capture from the atmosphere," Tech. Proc. of 2009 Clean Tech. Conf. and Trade Show, p. 175 (2009). [3] K. Littau, "System and method for recovery of CO2 by aqueous carbonate flue gas capture and high efficiency bipolar membrane electrodialysis," U.S. Patent Pending.