Treatment of saline wastewater and carbon dioxide capture using electrodialysis

Abstract

In this study, electrodialysis was used to achieve a combined action of capturing carbon dioxide and treating high-salinity water to produce hydrochloric acid, hydrogen gas, and carbonate and bicarbonate salts. Sodium chloride (NaCl) was selected as a representative salt of sea water. A six-chamber electrodialysis cell in which the chambers were separated by monovalent ion-exchange membranes was used for this process. The cathode and anode were made of titanium, with the anode being coated with mixed oxides of iridium and platinum to provide corrosion resistance. A parametric study was conducted to investigate the effects of NaCl concentration, flow rate of carbon dioxide, and voltage on the carbon dioxide sequestration and metal removal percentage. Under optimum conditions (NaCl concentration of 1 mol/l, voltage of 18.41 V and CO2 flow rate of 1.5 l/min), the amount of captured carbon dioxide was 8.196 g and sodium removal was 38.7%.