Liquid State Synthesis and CO2 Sorption Characteristics of Lithium Zirconates with Different Crystalline Phase

The temperature of the flue gas vent is about 573-773 K depended on following process of waste heat utilization and various CO₂ adsorbents applied at the according temperature are reported, in which, the lithium zirconates are promising candidates for their highly selective adsorption capacity at 673-973 K. In this paper, four kinds lithium zirconates with different chemical composition and crystalline phase (as shown in Fig. 1) are synthesized via a liquid phase co-precipitation method and the high-temperature CO₂ adsorption properties are evaluated. As shown in Fig. 2, both the tetragonal and monoclinic Li₂ZrO₃ exhibit similar sorption property as equation (1); The monoclinic Li₆Zr₂O₇ starts to adsorb CO₂ at 723-973 K as equation (2), yet no obvious desorption is detected; The rhombohedra Li₈ZrO₆ shows the largest adsorption capacity with two adsorption stages at 723-973 K and 973-1073 K, indicating that two different reactions (2) and (3) occur during the adsorption process. Further effects of calcinations temperature, particle size and surface area on the CO₂ sorption capacity will be discussed in the full manuscript. Li₂ZrO₃ + CO₂ → Li₂CO₃ + ZrO₂ (1) Li₆Zr₂O₇ + CO₂ → Li₂CO₃ + 2Li₂ZrO₃ (2) Li₈ZrO₆ + 3CO₂ → 3Li₂CO₃ + Li₂ZrO₃ (3)