Preparation of amine-modified SiO2 aerogel from rice husk ash for CO2 adsorption

Amine-modified SiO2 aerogel was prepared using 3-(aminopropyl)triethoxysilane (APTES) as the modification agent and rice husk ash as silicon source, its CO2 adsorption performance was investigated. The amine-modified SiO2 aerogel remains porous, the specific surface area is 654.24 m(2)/g, the pore volume is 2.72 cm(3)/g and the pore diameter is 12.38 nm. The amine-modified aerogel, whose N content is up to 3.02 mmol/g, can stay stable below the temperature of 300 A degrees C. In the static adsorption experiment, amine-modified SiO2 aerogel (AMSA) showed the highest CO2 adsorption capacity of 52.40 cm(3)/g. A simulation was promoted to distinguish the adsorption between the physical process and chemical process. It is observed that the chemical adsorption mainly occurs at the beginning, while the physical adsorption affects the entire adsorption process. Meanwhile, AMSA also exhibits excellent CO2 adsorption-desorption performance. The CO2 adsorption capacity dropped less than 10 % after ten times of adsorption-desorption cycles. As a result, AMSA with rice husk ash as raw material is a promising CO2 sorbent with high adsorption capacity and stable recycle performance and will have a broad application prospect for exhaust emission in higher temperature.