Study on CO2 adsorption capacity and kinetic mechanism of CO2 adsorbent prepared from fly ash

The use of fly ash from coal-fired power plants for CO2 adsorption can reduce CO2 emissions and CO2 capture costs while making efficient use of power plant solid waste. In this study, fly ash was used to prepare aerogel support with good microstructure, and the support was impregnated with an incipient wetness impregnation method to make CO2 adsorbent. Adsorption experiments of CO2 adsorbents were carried out in a self-designed small fixed-bed reactor to study the influence of reaction conditions on the adsorption capacity of adsorbents. The results showed that the aerogel support prepared from fly ash had good microscopic properties with specific surface area and specific pore volume were 400 m2/g and 1.9 cm3/g, respectively. The pore structure was uniform, and the proportion of mesopores reached more than 99%. Under the reaction condition of 60 °C reaction temperature, 15% water vapor concentration, 15% CO2 concentration and 500 mL/min total gas flow rate, the maximum adsorption capacity of KA-30 adsorbent was 2.02 mmol/g. Avrami fractional kinetics model was used to calculate the cumulative adsorption capacity to study the adsorption kinetics. Combined with mass transfer kinetic model and deactivation model, the experimental breakthrough curve was fitted to study the adsorption mechanism of the adsorbent.