Effects of amine loading on the properties of cellulose nanofibrils aerogel and its CO₂ capturing performance

In this work, cellulose nanofibrils (CNFs) were used to develop novel amine-based aerogels that can be applied as adsorbents for CO₂. Elemental analysis indicated that there was an increase in the C and N content when the concentration of aminosilane was higher. Moreover, Fourier transform infrared spectroscopy confirmed that the aminosilane had been grafted on the CNF. Thermal analysis and X-ray diffraction revealed that the thermal stability of the aerogel decreased after the modification, and the crystallinity decreased. However, the higher amine loading led to a rougher CNF surface and a larger average pore size, which favored the CO₂ capture. Furthermore, CNF grafted with aminosilane displayed a high CO₂ adsorption capacity (1.91 mmol/g 25 °C, 1 bar) and an easy regeneration process by heating at 80 °C. Therefore, the prepared polymer aerogels might have a highly potential use in the capture of CO₂.