Bioactivity Characterization of Amorphous Silica Ceramics Derived from Rice Husk Ash

Rice husk ash has been used to prepare amorphous silica bioactive ceramics. Three varieties of silica powders, namely brown ash, white ash and silica gel containing 96.0, 99.8 and 99.9% silica respectively, were used to prepare silica ceramics. The bioactivity and biodegradability properties of these ceramics were evaluated. The formation of crystalline apatite was observed on all the specimens in simulated body fluid. The phase composition, morphology and calcium/phosphorous ratio of the apatite layer formed were evaluated by X-ray Diffraction, Scanning Electron Microscopy and Energy Dispersive Spectroscopy. Controlled biodegradability of amorphous silica in Tris buffer solution was found. These results suggest that the amorphous silica derived from rice husk ash is a promising and cost effective biomaterial.