In-situ Fe/Ti doped amine-grafted silica aerogel from fly ash for efficient CO2 capture: Facile synthesis and super adsorption performance

Developing a cost-effective and high-efficiency solid sorbent for CO2 capture is current research focus. In this work, Fe/Ti doped in-situ amine-modified silica aerogel (AMSA) was synthesized from fly ash by grafting with 3-(Aminopropyl) triethoxysilane (APTES) via a simple ambient pressure drying process, and verified as an efficient sorbents for CO2 capture. The effects of experimental parameters such as acid leaching factors, gelling temperature and aging time, APTES concentration on the structure characteristics and CO2 adsorption properties of as-prepared AMSAs were investigated in detail. Results demonstrated that the AMSAs exhibited a high CO2 adsorption ability of 4.95 mmol∙g−1 at 70 °C, and maintained 94.3 % of their maximum capacity after 10 adsorption–desorption cycles, indicative of long cycle stability of the sorbent. Moreover, the adsorption equilibrium Langmuir isotherm model was established while the kinetic adsorption behavior was well simulated by the double exponential model. This facile and environmental-friendly synthesis method may provide a novel reference for enhanced CO2 capture sorbents from solid waste.