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

Abstract 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 NaHCO 3 products from CO 2 and NaCl feed. Cell operation consisted of feeding the cell with carbonic acid (CO 2 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 NaHCO 3 were ∼0.05 mM cm −2  h −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.