Synthesis and CO2 Adsorption Characteristics of Lithium Zirconates with High Lithia Content
Pure monoclinic phase Li6Zr2O7 and rhombohedral phase Li8ZrO6 that coexisted with a fraction of Li6Zr2O7, are synthesized by a liquid phase coprecipitation method and characterized by X-ray diffraction, scanning electron microscopy, and thermo-gravimetric analysis. The high-temperature CO2 uptake properties of both samples are systematically investigated. The temperature effect tests indicate that, in the case of low temperature (<973 K), both of the adsorbents exhibit slow CO2 uptake rates because of the inhibited diffusion of CO2 in the solid carbonate shell; while at the temperature above the melting point of Li2CO3 (about 983 K), the CO2 uptake rates are enhanced dramatically for both Li6Zr2O7 and Li8ZrO6, and achieved about 12.3% weight gain and 35.0% weight gain within 15 min at 1073 K, respectively. The thermal stability tests indicate that both samples exhibit gradually reduced capacities during the multicycle processes. The analysis of the crystalline structure reveals that the reduced capacities are resulted from the loss of lithia under high temperatures. Finally, the possible adsorption pathways for both monoclinic phase Li6Zr2O7 and rhombohedral phase Li8ZrO6 are suggested as well.
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Document Type: Research Article
Affiliations: State Key Lab of Chemical Engineering, College of Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, China
Publication date: 2010-09-01