Microstructural Thermal Evolution of the Na₂CO₃Phase Produced during a Na₂ZrO₃–CO₂Chemisorption Process

Abstract

Na 2 ZrO 3 was synthesized by a solid-state reaction, and a CO 2 chemisorption process was evaluated as a function of temperature to determine whether structural and/or microstructural modifications occurred during the reaction process. This study was performed using the following techniques: thermogravimetry, X-ray diffraction, scanning and transmission electron microscopy, and N 2 adsorption. The results clearly show that Na 2 CO 3 −ZrO 2 was produced on the external shell of Na 2 ZrO 3 during the CO 2 chemisorption process. The microstructural properties varied as a function of temperature. The Na 2 ZrO 3 −CO 2 chemisorption reaction was not limited at T ≤ 550 °C because the Na 2 CO 3 −ZrO 2 external shell contained mesopores. CO 2 diffused through the mesoporous shell, and the reaction continued. Conversely, if the CO 2 chemisorption occurred at T > 550 °C, the mesoporosity on the Na 2 CO 3 −ZrO 2 external shell was not observed, and the chemisorption was kinetically controlled by the diffusion of CO 2 through the sodium crystal phases.

Influence of the K‐, Na‐ and K‐Na‐carbonate additions during the CO2 chemisorption on lithium oxosilicate (Li8SiO6)

“…At temperatures higher than 550 °C, the mesoporosity disappears due to sintering eff ects and the CO 2 chemisorption process continues through out intercrystalline diff usion processes. 36 Figure 3 schematizes the thermal evolution involved in this reaction mechanism. First, between 300 and 465 °C, the sample gained ~4.5 wt%, attributed to the superfi cial reaction.…”

Effects of sodium precursors and gelling agents on CO2 sorption performance of sodium zirconate

“…[21] This value is very low compared to Na 2 ZrO 3 with ca. 1.590 mmol/g at 300°C and 100 kPa [11] and ca. 3.790 mmol/g at 600°C and 100 kPa [9] which were prepared by solid-state reaction, and ca.…”

“…Other sodium and zirconium precursors such as sodium acetate and zirconium acetylacetonate were also reportedly used for the synthesis of Na 2 ZrO 3 . [5,6,10,11] However, the effects of using different precursors on the CO 2 adsorption properties of Na 2 ZrO 3 were not studied in these reports. Zhao and colleagues [12] recently compared the use of sodium citrate and sodium acetate as sodium precursors, and zirconyl nitrate and zirconoxy chloride as zirconium precursors for liquid-state synthesis of Na 2 ZrO 3 and proved that the choice of precursors used to synthesise Na 2 ZrO 3 was crucial in producing Na 2 ZrO 3 with high purity, CO 2 capture activity and regeneration stability.…”

Catalytic Constructive Deoxygenation of Lignin-Derived phenols: New C–C Bond Formation Processes from Imidazole-Sulfonates and Ether Cleavage Reactions

“…Among the alkaline and/or alkaline-earth oxides, various lithium, sodium, potassium, calcium and magnesium ceramics have been proposed for CO 2 capture through adsorption and chemisorption processes [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. These materials can be classified into two large groups: dense and porous ceramics.…”

“…Some of the diffusion processes correspond to the CO 2 diffusion through the mesoporous external carbonate shell, and some others such as the intercrystalline and grain boundary diffusion processes [1,18,21]. Figure 1 shows the theoretical CO 2 chemisorption capacities (mmol of CO 2 per gram of ceramic) for the most studied alkaline and alkaline-earth ceramics.…”