Citrate Sol–Gel Method for the Preparation of Sodium Zirconate for High-Temperature CO2 Sorption

The use of sorbents capable of capturing high-temperature CO 2 increases the overall efficiency of CO 2 removal processes, without the need for cooling the flue gases. In this study, Na 2 ZrO 3 for high-temperature CO 2 sorption was newly prepared using a citrate sol–gel method. The characteristics and CO 2 sorption behavior of the prepared Na 2 ZrO 3 were examined by field-emission scanning electron microscopy, N 2 adsorption analysis, X-ray diffraction, and thermogravimetric analysis, and compared with those of Na 2 ZrO 3 synthesized using a conventional solid-state method. Na 2 ZrO 3 could be synthesized at lower temperature by using the citrate sol–gel method compared to the case of solid-state method. Na 2 ZrO 3 prepared using the citrate sol–gel method showed excellent CO 2 sorption performance: high sorption capacity (17.5–21.0 wt % at 823 K and 1 bar), fast sorption kinetics, and good cycling stability. Kinetic analysis was also conducted by fitting the CO 2 sorption behavior to the double exponential model.