Alumina-extracted residue-derived silica foams with ultra-large pore volume for highly superior post-combustion CO2 capture

Sodium silicate solution obtained by alkali dissolving alumina-extracted residue (AR) of coal ash was used to fabricate mesoporous silica foam (MSF). The MSF supports can load with 80 wt% amine polymers due to its ultra-large pore volume, thus obtaining the maximum CO2 adsorption capacity of 6.46 mmol/g under 75 °C and dry 100% CO2 atmosphere. Moreover, the sorbents presented fast adsorption kinetics, low adsorption heat and regeneration heat, and stable adsorption-desorption cycle performance. Amine impregnated MSF derived from AR was a promising alternative for post-combustion CO2 capture of power plant flue gas in the future.