Activated carbon was prepared from cellulose-based aerogel (aerocellulose) monoliths by carbonization and subsequent CO2 activation. The monolithic structure of the as-synthesized aerocellulose was retained during the carbonization and activation processes. The as-synthesized aerocellulose monolith was mainly mesoporous with well-developed surface area, large total pore volume, with only moderate CO2 uptake. In order to enhance CO2 adsorption, microporosity of carbonized aerocellulose was increased upon CO2 activation. The resulting activated carbon showed an enhanced specific surface area of ~750 m2 g−1, total pore volume of 0.43 cm3 g−1, and volume of micropores (pore widths <2 nm) of ~0.27 cm3 g−1. Activation of carbonized aerocellulose resulted in about five-fold increase in the specific surface area and over 27-fold increase in the volume of micropores as compared to the as-synthesized material. The resulting activated carbon showed excellent adsorption properties toward CO2 reaching 5.8 mmol g−1 of CO2 at 0 °C and 1 atm and 3.7 mmol g−1 of CO2 at 25 °C and 1.2 atm. High microporosity and surface area of the activated aerocellulose-derived carbon combined with its biocompatibility, biodegradability, non-toxicity, low cost, and good thermal stability makes this material beneficial for CO2 capture at ambient temperatures.
- CO sorption
- Sol–gel process