The Investigation of SiO₂ structure obtained from the combustion of rice husk

Abstract

In this work, SiO2 was obtained from the combustion of rice husk. The influence of temperature on its structure and morphology was investigated. At low combustion temperatures, the rice husk ash appeared to be black due to an insufficient temperature for the oxidation process. When the temperature was raised to 1000°C, the color changed to a pale pink. The elemental composition of the rice husk ash was determined by means of x-ray photoelectron spectroscopy. The survey analysis of the XPS spectra revealed the existence of Si, O, C, Ca P, K and N. The elemental fraction of Si was increased as a function of temperature. However, the N 1s XPS signal can be collected from the rice husk after the combustion at 300°C only. Si L edge XANES spectra were recorded to determine the structure of the SiO2. The results suggested the similarity between the SiO2 structure of the rice husk ash and the standard SiO2. The microstructure of the rice husk ash was studied by SEM. It was clearly seen that the pores were created on the rice husk ash. By increasing the pyrolysis temperature, the cellulosic material was removed and consequently produced channels.