Preparation of amine functionalized micro-mesoporous silicon adsorbent from fly ash and its kinetic characteristics of CO2 adsorption/desorption process

Micro-mesoporous silicon materials were prepared using silicate filtrate produced from fly ash as a silicon source. Then, the micro-mesoporous silica material was used as the carrier and amine compounds as modifiers to prepare a micro-mesoporous CO 2 adsorbent. Afterwards, the structural properties, surface groups, thermal stability of micro-mesoporous silicon materials and micro-mesoporous CO 2 adsorbent were studied. The results reveal that the micro-mesoporous CO 2 adsorbent maintains the same micro-mesoporous structure as the micro-mesoporous silica material. And the thermal stability temperatures of adsorbent is below 383 K. Later, the CO 2 adsorption performance and kinetic characteristics of adsorption process were studied through thermogravimetric analysis (TGA) and adsorption column experiments. The results indicated that the optimal CO 2 adsorption capacity of 2.31 mmol/g-adsorbent was achieved at 343 K, and the adsorption capacity remained basically unchanged after 10 adsorption/desorption cycles. Dynamics studies have shown that the Avrami fraction model fits the CO 2 isothermal adsorption curve very well, and the fitting results reveal that the intra-particle diffusion dominates the speed of the adsorption process. Additionally, the Yasyerli deactivation model can perfectly fit the CO 2 adsorption breakthrough curve, and the fitting results indicate that the CO 2 adsorption process is the deactivation process of the adsorbent. Finally, the adsorption/desorption kinetic simulation parameters can be used for the design and optimization of CO 2 adsorption and desorption processes in industry.