Maize Husk Ash as a Renewable Source for the Production of Value Added Silica Gel and Its Application

Nowadays, silica gels have developed a lot of interest due to their extraordinary properties and their existing and potential applications in science and technology. Silica gel has a lot of applications such as a desiccant, as a preservation tool to control humidity, as an adsorbent, as a catalyst and as a catalyst support. Silica gel is a rigid three-dimensional network of colloidal silica, and is classified as: aquagel, xerogel and aero-gel. Extraction of amorphous silica from Maize Husk Ash (MHA) was carried out in this study. Silica xerogel was produced by dissolving MHA with alkali solution to form sodium silicate solution and lowering the pH to7 by adding hydrochloric acid to form silica aquagel followed by drying to form silica xerogel. The silica xerogel was characterized using SEM, XRD and FTIR techniques. Silica and mineral contents of MHA and xerogel were determined by EDS, X-ray diffraction patterns revealed amorphous nature of extracted silica. Fourier transform infrared (FTIR) data indicates the presence of siloxane and silanol groups. Silica yield from MHA was 56.32% while moisture content was 2.89% and also the SEM presented appropriated morphological characteristics of the best silica. MHA proved to be a potential low cost raw material for the production of silica gel.