No abstract

Using diatomite and analytical pure SiO 2 as silicon sources, Li 4 SiO 4 sorbents for high temperature CO 2 capture were prepared through solid-state reaction method. Phase composition was analyzed by X-ray diffraction, and the CO 2 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 CO 2 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 SiO 2 (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. The increasing CO 2 concentration in the atmosphere due to fossil fuel burning has been considered as a major contributor to the global warming. So the separation, recovery and storage/utilization of CO 2 have attracted considerable attention in recent years. CO 2 can be removed from flue gas and waste gas streams by various methods such as membrane separation, wet absorption, and dry absorption [1][2][3][4]. However, these methods need to consume a lot of energy. Hence, the materials with high CO 2 capture capacity at high temperature are desirable. In recent years, the development of regenerable sorbents for high temperature CO 2 capture has received increasing attention [5][6][7]. Compared with other sorbents, Li 4 SiO 4 has the better CO 2 absorption properties over a wide range of temperature and CO 2 concentration [8,9]. In order to study the absorption mechanism of Li 4 SiO 4 materials, some researchers made some kinetic study about Li 4 SiO 4 materials [10]. However, kinetic study about different silicon sources has not been reported.In this paper, we firstly developed novel low-cost Li 4 SiO 4 sorbents for high temperature CO 2 capture using diatomite as silicon source. The effect of different silicon sources on the absorption capacity was investigated by studying their kinetic characteristics. In the following paper, DS and AS stand for diatomite and analytical pure SiO 2 , respectively.