Preparation and kinetic analysis of Li4SiO4 sorbents with different silicon sources for high temperature CO2 capture

Using diatomite and analytical pure SiO₂ as silicon sources, Li₄SiO₄ sorbents for high temperature CO₂ capture were prepared through solid-state reaction method. Phase composition was analyzed by X-ray diffraction, and the CO₂ absorption capacity and absorptoin-desorption performance were studied by the simultaneous thermal thermogravimetric analyzer (TG-DSC). The results showed that silicon source had an important influence on CO₂ absorption properties. The kinetic parameters for the chemisorption and diffusion processes were obtained by the isothermal study for different silicon sources. The results showed that the activation energies for these two processes were estimated to be 105.427 and 35.928 kJ/mol for the sample with analytical pure SiO₂ (AS). While for the sample with diatomite (DS), the activation energies for these two processes were estimated to be 78.500 and 20.439 kJ/mol, respectively.