Preparation of silica powder from rice husk

Abstract

Silicon dioxide (SiO₂) is the most abundant mineral in the world.  Plants are the source of this mineral.  In recent decades, with the advent of nanotechnology, silica nanoparticles have been found new applications in chemical industry, textile, packaging, biotechnology, agriculture and medicine.  Rice husk and straw are rich sources of minerals.  Rice husk (RH) has more than 20% silica.  Using thermal process in presence of different gasses, the sample of ash of husk and bran of rice produced.  To investigate the effect of heat treatment in different conditions, the properties of the samples were determined. Rice husk ash solution was poured on soda solution.  Then silica was separated and sodium silicate was formed.  By separation and titration of the solution, silica was obtained.  The obtained silica washed by hydrochloric acid and purified.  By repeating process on soda solution and titration under controlled conditions and by adding the surfactants silica nanoparticles were obtained.  In this study, amorphous silica nanoparticles with an average size of 60 nm were produced by chemical reduction method.  Fourier transform infrared (FT-IR) was used for Infrared spectroscopy analysis and X-ray diffraction was used for identification phase.  For elemental analysis, the inductively coupled plasma emission spectrometer (ICP/ES) and energy dispersive X-ray analysis (EDAX) were used.