Analysis of the CO2 capture in sodium zirconate (Na2ZrO3). Effect of the water vapor addition

Sodium metazirconate (Na2ZrO3) was synthesized, by solid-state reaction, and characterized. Water sorption experiments were performed using N-2 and CO2 as carrier gases. In the absence of CO2, Na2ZrO3 showed considerably high water vapor sorption owing to two different processes, hydroxylation and water vapor adsorption. When CO2 was used as the water vapor carrier gas, the reactivity of Na2ZrO3 was found increased as a result of the reaction producing NaHCO3 and ZrO2. These results reveal that, at least in the measured temperature range, Na2ZrO3 is able to take-up 2 mol of CO2 compared to 1 mol of CO2 measured under dry conditions, as the final product is sodium bicarbonate (NaHCO3). In other words, the theoretical CO2 absorption capacity on Na2ZrO3 is 10.8 mmol/g, when water vapor is added. Finally, a kinetic analysis and the reaction mechanism are presented for Na2ZrO3 carbonation process in the water vapor presence. (C) 2011 Elsevier Ltd. All rights reserved.