Influence of concentration of pore forming agent on porosity of SiO2 ceramic from rice husk ash

Pore forming agent is a pyrolysable material which burns out during firing. Preparation of porous ceramics with controlled microstructure can be made using different pore forming agents such as wheat particles, starch, PMMA, poppy seed and saw dust. Porous silica, a ceramic, was successfully synthesised using rice husk ash as the silica precursor via sol-gel process and employing yeast as the pore forming agent. Yeast, a biological agent was added in increasing amounts to a sol-gel silica system at solution level along with additives such as glucose and water that allow the biological agent to multiply and grow and in the process form porous ceramic structure. The porous ceramic was dried in an oven at 110 degrees C overnight. The resultant ceramic was characterised in terms of product density, particle size, surface area and pore volume using gas pycnometer and BET sorptometer respectively. The specific surface areas ranged from 163.4 to 200.7 m(2) g(-1) while for the pore volume the range was from 0.3410 to 0.4879 cm(3) g(-1).