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An efficient CO2 adsorbent with a hierarchically micro-mesoporous structure and a large number of amine groups was fabricated by a two-step synthesis technique. Its structural properties, surface groups, thermal stability and CO2 adsorption performance were fully investigated. The analysis results show that the prepared CO2 adsorbent has a specific hierarchically micro-mesoporous structure and highly uniformly dispersed amine groups that are favorable for the adsorption of CO2. At the same time, the CO2 adsorption capacity of the prepared adsorbent can reach a maximum of 3.32 mmol-CO2/g-adsorbent in the actual flue gas temperature range of 303–343 K. In addition, the kinetic analysis results indicate that both the adsorption process and the desorption process have rapid adsorption/desorption rates. Finally, the fitting of the CO2 adsorption/desorption experimental data by Avrami's fractional kinetic model shows that the CO2 adsorption rate is mainly controlled by the intra-particle diffusion rate, and the temperature has little effect on the adsorption rate. [ABSTRACT FROM AUTHOR]

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. [Display omitted] [ABSTRACT FROM AUTHOR]