Biomass Fly Ash as an Alternative Approach for Synthesis of Amorphous Silica Nanoparticles with High Surface Area

In this study, the monodisperse amorphous silica nanoparticles (SiO2 NPs) with uniform size distribution and high surface area were successfully synthesized from fly ash as a silica source by chemical sol-gel method. The influence of reaction conditions such as surfactant concentration, aging temperature (Ta), and aging time (Ta) on formation of SiO2 NPs was investigated. Through SEM characterization, it was founded that the uniform and small spherical SiO2 NPs with diameter of 20-30 nm could be synthesized at the appropriate CTAB content of 3 wt%, Ta of 60 °C, and Ta of 8 h. In addition, XRD and nitrogen adsorption-desorption measurements indicated that the SiO2 NPs were obtained under amorphous structure, which possesses a high specific surface area of 408 m2 g-1. The obtained results imply that the successful synthesis of SiO2 NPs from fly ash not only displays an effectively alternative approach to provide high quality SiO2 NPs for various necessary applications but also help solving environmental issues due to large amount of fly ash waste each year.