| Abstract
| - Lithium zirconate (Li2ZrO3) is one of the most promisingmaterials for CO2 separation from flue gas at high temperature.This material is known to be able to absorb a largeamount of CO2 at around 400−700 °C. However, themechanism of the CO2 sorption/desorption process on Li2ZrO3 is not known yet. In this study, we examined theCO2 sorption/desorption mechanism on Li2ZrO3 by analyzingthe phase and microstructure change of Li2ZrO3 duringthe CO2 sorption/desorption process with the help ofthermogravimetric analysis (TGA), differential scanningcalorimetry (DSC), and X-ray diffraction (XRD) analyses. Li2ZrO3 powders were prepared from lithium carbonate (Li2CO3) and zirconium oxide (ZrO2) by the solid-state method,and the CO2 sorption/desorption property was examinedby TGA. It was shown that pure Li2ZrO3 absorbs a largeamount of CO2 at high temperature with a slow sorptionrate. Addition of potassium carbonate (K2CO3) and Li2CO3 inthe Li2ZrO3 remarkably improves the CO2 sorption rate ofthe Li2ZrO3 materials. DSC analysis for the CO2 sorption processindicates that doped lithium/potassium carbonate is inthe liquid state during the CO2 sorption process and playsan important role in improving the CO2 uptake rate. XRDanalysis for phase and structure change during the sorption/desorption process shows that the reaction between Li2ZrO3 and CO2 is reversible. Considering all data obtained inthis study, we proposed a double-shell model to describethe mechanism of the CO2 sorption/desorption on bothpure and modified Li2ZrO3.
|
