CO2 Fixation Process with Waste Cement Powder via Regeneration of Alkali and Acid by Electrodialysis: Effect of Operation Conditions

The effect of the operation conditions on the recovery of acid–alkali pairs by electrodialysis was studied to improve the efficiency of the newly developed mineral carbonation process for carbon dioxide fixation. Sodium nitrate (NaOH + HNO3), sodium chloride (NaOH + HCl), and potassium chloride (KOH + HCl) showed almost equal performance in the recovery process for the two fixed membrane configurations. For the same salt, the configuration of anion-exchange membrane bipolar membrane (AEM–BPM) showed higher recovery rate and lower power consumption than the cation-exchange membrane bipolar membrane (CEM–BPM) configuration. Significantly higher recovery rates were observed when potassium acetate was used for the CEM–BPM configuration. A higher recovery rate was observed for a lower initial concentration, but the power consumption was lower for higher initial concentrations. Calcium in waste cement powder can be rapidly leached with acetic acid. The results showed that the process performance would be significantly improved by using acetic acid for calcium leaching, and sodium hydroxide for CO2 capture.