Synthesis and characterization of amine impregnated silica aerogel from rice husk for CO2 adsorption

Objective: Rice husk has attracted considerable attention in recent years due to its chemical components that are beneficial for a wide range of applications. In this paper, silica aerogel from Rice Husk Ash (RHA) was prepared through sol-gel processing and ambient pressure drying. Methods: The silica RHA was extracted with sodium hydroxide solution to produce sodium silicate solution and neutralized with sulphuric acid to form silica gel. Then, the silica aerogel was further modified with an amine, 3-(aminopropyl) triethoxysilane (APTES), because amine groups provide specific adsorption sides for CO2 adsorption. The functional group, surface morphology, and elemental composition of rice husk, silica aerogel, and modified silica aerogel were characterized by Fourier transform infrared spectroscopy (FTIR), Scanning Electronic Microscopy (SEM) and Elemental Analysis (EA). Results: For amine-modified silica aerogel, it was found that the sample consists of N-H band at a certain peak. FTIR and SEM analysis revealed that the synthesized silica aerogel has fibrous morphology and indicates a similar trend with previous researches. The aminemodified silica aerogel (AMSA) is able to adsorb 0.88 mol CO2/kg AMSA. Concluson: This study shows that the rice husk silica aerogel modified with APTES could enhance the CO2 adsorption performance due to the physisorption and chemisorption. © 2020 Bentham Science Publishers.