Synthesis, Characterization and Application of Amine-Functionalized Hierarchically Micro-Mesoporous Silicon Composites for CO Capture in Flue Gas.

An efficient CO 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 CO adsorption performance were fully investigated. The analysis results show that the prepared CO adsorbent has a specific hierarchically micro-mesoporous structure and highly uniformly dispersed amine groups that are favorable for the adsorption of CO. At the same time, the CO adsorption capacity of the prepared adsorbent can reach a maximum of 3.32 mmol-CO/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 CO adsorption/desorption experimental data by Avrami's fractional kinetic model shows that the CO adsorption rate is mainly controlled by the intra-particle diffusion rate, and the temperature has little effect on the adsorption rate.