Amine-impregnated silicic acid composite as an efficient adsorbent for CO2 capture

A new high efficiency inorganic–organic composite solid sorbent was developed by the simple impregnation of aminoethylethanolamine (AEEA) on the nanoporous silicic acid (SiO(OH)2) for CO2 capture from flue gas. Experimental results revealed that amine loading amount, adsorption temperature, and moisture addition could greatly affect the CO2 adsorption capacity. At the optimal AEEA loading of 55 wt%, the CO2 sorption capacity reached a maximum value of 4.54 mmol/g at 25 °C under 10 vol% CO2and 10 vol% H2O. To the best of our knowledge, this is the first time that an AEEA based adsorbent has been reported as an efficient adsorbent for CO2 capture. The AEEA impregnated SiO(OH)2 also had good stability and reusability during cyclic adsorption/desorption tests, and the sorption capacity loss may be recovered by mixing condensed AEEA with cyclic sorbents. The Avrami’s fractional order kinetic model was applied for the kinetic analysis of CO2 adsorption and desorption on the optimized sorbent. The obtained activation energy for CO2 desorption was 33.5 kJ/mol. The estimated regeneration heat duty on the optimized AEEA sorbent was 53.29 kJ/mol CO2, a great energy penalty reduction compared to that of a typical aqueous monoethanolamine system.