Carbon dioxide mineralization by electrode separation for quick carbon reduction and sequestration in acidified seawater

Abstract

Aiming to sequestrate the excessive carbon dioxide and convert the acidified seawater, an improved method of carbon dioxide mineralization is developed based on electrode separation mechanism and extra oxygen-supplying technique. By electrode separation the neutralizations of the anodic acidity and the cathodic alkalinity, as well as the precipitation and the dissolution of calcium carbonate (CaCO3), are prevented. In addition, the extra-supplied oxygen prevents the evolution of hydrogen, which enhances the electric conductivity of the porous cathode and the deposition of CaCO3. A series of indoor physical experiments were conducted and the results show that the acidified seawater was successfully converted to alkaline in 72h. The speed of carbon mineralizing sequestration is significantly enhanced by supplying extra oxygen. The carbon dioxide mineralization speed increases with the immerse ratio of the aerator due to the more reacted oxygen and the less hydrogen evolution, which gives more porous space in the cathode for more conductive seawater and more deposition of CaCO3. The extra-supplied oxygen increases the CaCO3 -deposition by 100-214% under excessive atmospheric- CO2 conditions and 117-200% under normal atmospheric- CO2 conditions, respectively. This method has an application potential for quick conversion of locally acidified seawater in emergent circumstances.