Pyrolysis method of gel SiO2/chitosan for the preparation amorphous silica nanoparticles from waste rice husk ash

Rice husk ash (RHA) is obtained from industrial waste from drying manufacture and easily available in Vietnam. However, for commercial viability, and for many applications, the pyrolysis method of SiO2/chitosan gel to prepare silica nanoparticles with small particle size ( 10 nm) should not only be as efficient as possible but also adjustable particle size. This study characterized the elemental composition, crystallinity, size and morphology of silica nanoparticles obtained from industrial waste RHA was surveyed by Energy-dispersive X-ray, X-ray diffractograms and Transmission electron microscope. Silica nanoparticles have average diameter of about 9.0 ± 1.9 nm, narrow particle size distribution, high silica content of 99.56% and almost amorphous structure which has one peak at 2θ ~22.1°. Silica nanoparticles separated which may be due to the presence of hydrogen bonding between silanol groups of silica and –OH groups on the surface of chitosan. Fourier Transform Infra-Red spectra confirmed the presence of –OH groups and O-Si-O bonds of silica nanoparticles.