CO₂ capture performance and characterization of cellulose aerogels synthesized from old corrugated containers

Old corrugated containers with low recyclability were used as raw materials to synthesize a series of aerogels with varying cellulose concentrations in NaOH/urea solution via a freeze-drying process. The resulting aerogels had a rich porous structure with specific surface areas in the range of 132.72-245.19 m².g^-1 and mesopore volumes in the range of 0.73-1.53 cm³.g^-1, and were tested for CO₂ sorption at ambient temperature and pressure, displaying excellent CO₂ adsorption capacities in the range of 1.96-11.78 mmol.g^-1. Furthermore, the CO₂/N₂ selectivity of aerogels decreased with decreasing specific surface area, which was mainly caused by the decrease in CO₂ capture. In addition, the CO₂ sorption capacity of the sample with 2% cellulose content, CA-2, exceeded the values reported so far for many other sorbents with higher specific surface areas, and showed reasonable cyclic stability for CO₂ capture. Therefore, this adsorbent represents an attractive prospect for CO₂ uptake at room temperature.