Conversion of saline water and dissolved carbon dioxide into value-added chemicals by electrodialysis

• Published in: Journal of CO2 utilization 2017-05, Vol.19, p.177-184
• Main Authors: Dara, Saad, Lindstrom, Michael, English, Joseph, Bonakdarpour, Arman, Wetton, Brian, Wilkinson, David P.
• Format: Article
• Language: English
• Subjects: CO2 conversion; Electrodialysis; Waste water
• ISSN: 2212-9820; 2212-9839
• DOI: 10.1016/j.jcou.2017.03.013

Power couple: A new approach that simultaneously converts carbon dioxide and desalinates water is demonstrated.▪ •Simultaneous conversion of carbon dioxide and desalination of waste-water by electrodialysis.•Carbon dioxide converted to mineralized form.•Development of mathematical model to identify limitations of approach. We demonstrate a new approach that simultaneously converts dissolved carbon dioxide and high salinity waste-water to desalinated water and value-added chemicals in the form of inorganic acids and carbonate salts. A four compartment electrodialysis cell module using anion exchange and cation exchange membranes, and a Pt/Ir-coated Ti anode and Ti mesh cathode was used to produce HCl and NaHCO3 products from CO2 and NaCl feed. Cell operation consisted of feeding the cell with carbonic acid (CO2 dissolved in water) and a saline solution of sodium chloride. Under an applied voltage clear production of inorganic carbon salts and acids was demonstrated. The product fluxes for HCl and NaHCO3 were ∼0.05mMcm−2h−1 on average. A mathematical model for this electrodialysis cell configuration was developed to better understand limitations within the cell which are not available from experimental data including concentration profiles within the intra-membrane channels.