Dynamic capture of low-concentration CO2 on amine hybrid silsesquioxane aerogel

Abstract

Amine hybrid silsesquioxane aerogel (AHSA) was synthesized through a single-step sol–gel process followed by supercritical drying. CO2 adsorption performances of highly porous AHSA in 1% CO2 were investigated. 50°C is preferred to perform the CO2 capture of AHSA to achieve a CO2 adsorption capacity of 3.04mmol/g (dry) or 3.84mmol/g (humid) under given conditions. A rise in adsorption gas flow rate from 300 to 700ml/min results in the decrease of CO2 adsorption capacity from 3.04 to 2.42mmol/g. The CO2 adsorption rate is mainly affected by the gas flow rate, while the effect of temperature can be ignored. Different with the adsorption performance, the CO2 desorption kinetics of AHSA is mainly affected by the temperature, the effect of gas flow rate is indifferent. Water favors the CO2 capture capability of AHSA, however, it is bad for the CO2 adsorption and desorption kinetics. The CO2 adsorption capacities of AHSA in 1% CO2 are much higher than those of other amine based porous adsorbents obtained with a 1% or even higher CO2 gas mixture. Also, AHSA has very short adsorption half time (22–55s) and low desorption temperature of 80°C, much lower than those of other amine-based adsorbents. The resulting adsorbent is dynamic and possesses excellent regenerability for low-concentration CO2 capture.