Amine-Impregnated Elastic Carbon Nanofiber Aerogel Templated by Bacterial Cellulose for Co2 Adsorption and Separation

Abstract

Reducing the concentration of carbon dioxide (CO2) in ambient air is essential to slow down the global warming process. How to effectively apply carbon adsorbent materials in large-scale industries is an urgent research need nowadays. Carbon aerogels have emerged as promising candidates for CO2 capture due to their large specific surface area, well-developed pore structure, tunable porosity, and insensitivity to moisture. However, most of the carbon-based materials suffer from poor mechanical properties, low recycling efficiency, and low adsorption capacity, making it difficult to be put into industrial applications on a large scale. Bacterial cellulose (BC) has an ultra-fine reticular structure, a modulus of elasticity that is several to more than ten times that of typical plant fibers, and high tensile strength. In this paper, BC was treated by unidirectional freeze-drying method, and the aerogels with ordered honeycomb pore structure were constructed by unidirectional growth of ice crystals, and the pyrolytic chemical properties of BC were adjusted by using (NH4)2SO4, which effectively prevented the shrinkage and deformation of materials during carbonization, and successfully prepared elastic nanocarbon fiber aerogels. At the same time, the introduction of (NH4)2SO4 made the material realize N doping in the carbonization process, providing more adsorption sites, which was conducive to the adsorption of CO2. Finally, the carbon fiber nanoaerogel was modified by TEPA to further improve its adsorption selectivity for CO2. The prepared elastic carbon nanofiber aerogel (CBCNT) has high CO2 adsorption performance and high selectivity, and its CO2 capture capacity is up to 4.88 mmol/g.

Keywords: CO2 capture, Bacterial cellulose, Elasticity, Carbon aerogels, Honeycomb channel structure