Utilization of rice husk (Oryza sativa) for amorphous biosilica (SiO2) production as a bacterial attachment

Abstract

Rice husk as a by-product of the rice milling process has not been utilized optimally. The yield of rice husk waste continues to increase from year to year, considering that Indonesia is the third largest rice producer in the world. Rice husk has a fairly large silica content; therefore, rice husk is widely used as an alternative source of silica. The purpose of this study is to synthesize silica from rice husk and analyse its characteristics. The research method used in silica isolation was carried out by non-thermal and thermal methods. Non-thermal method for removal of inorganic compounds and hydrolysis of organic compounds by acidic solutions (HCl), while the thermal method is carried out by burning rice husks at a temperature of 500 °C to produce rice husk ash. The resulting rice husk ash was processed by the sol-gel method. The resulting silica was determined of its morphology by Scanning Electron Microscopy (SEM), composition, and structure with Fourier Transform Infrared Spectroscopy (FT-IR). The results obtained in this study were white silica with a yield of 84.782%. Biosilica produced is then mixed with certain bacteria, either Serratia sp or Bacilus pumilus. Then, the attachment of bacteria was evaluated by using SEM (Scanning Electron Microscopy).