Thermodynamic and Kinetic Analyses of the CO₂ Chemisorption Mechanism on Na₂TiO₃: Experimental and Theoretical Evidences

Sodium metatitanate (Na 2 TiO 3 ) was successfully synthesized via a solid-state reaction. The Na 2 TiO 3 structure and microstructure were characterized using X-ray diffraction, scanning and transmission electron microscopy, and N 2 adsorption. Then, the CO 2 chemisorption mechanism on Na 2 TiO 3 was systematically analyzed to determine the influence of temperature. The CO 2 chemisorption capacity of Na 2 TiO 3 was evaluated both dynamically and isothermally, and the products were reanalyzed to elucidate the Na 2 TiO 3 –CO 2 reaction mechanism. Different chemical species (Na 2 CO 3, Na 2 O, and Na 4 Ti 5 O 12 or Na 16 Ti 10 O 28 ) were identified during the CO 2 capture process in Na 2 TiO 3 . In addition, some CO 2 chemisorption kinetic parameters were determined. The Δ H ⧧ was found to be 140.9 kJ/mol, to the Na 2 TiO 3 –CO 2 system, between 600 and 780 °C. Results evidenced that CO 2 chemisorption on Na 2 TiO 3 highly depends on the reaction temperature. Furthermore, the experiments were theoretically supported by different thermodynamic calculations. The calculated thermodynamic properties of CO 2 capture reactions by (Na 2 TiO 3, Na 4 Ti 5 O 12, and Na 16 Ti 10 O 28 ) sodium titanates were fully investigated.