Adsorption characteristics of amine-modified carbon aerogel nanoparticles in CO2 fluids

Understanding the adsorption mechanism of CO2 fluid on porous media is significant for developing efficient CO2 adsorbents. This study modified carbon aerogel (CA) nanoparticles with N-methylethanolamine (MMEA). The surface functional groups and pore properties of the samples were characterized, and the flow and adsorption behavior of fluids under different pressures in the pores were studied. The results showed that carbon aerogel's amine and oxygen-containing functional group content increased with the increase in MMEA loading but decreased its specific surface area and pore volume. The adsorption capacity of 15 wt. % (15%MMEA-CA) was the highest at 144 cm3/g, which was 32% higher than that of the original sample. After ten cycles, the cycle efficiency of the adsorbent was more than 86%. The results show that the amine-modified carbon aerogel nanoparticles can efficiently adsorb CO2 in fluid and become promising adsorbents. The isothermal adsorption model of Toth and Dubinin-Astakhov can fit the adsorption process well, indicating that the adsorption process of CO2 fluid on MMEA-modified CA nanoparticles occurs on a non-uniform surface, which is a combination of single-molecular layer adsorption and microporous layer filling. These conclusions provide valuable insights into the adsorption kinetics of gases in porous nanoparticles, which has important implications for climate change mitigation and sustainable development.