Mesoporous silica powder for dental restoration composites from rice husk: a green sol–gel synthesis

Morphologically organized non-crystalline silica powder was synthesized from rice husk by a green sol–gel route. Amorphous sphere-shaped silica powder with a surface area of ~ 370 m2 g−1, particle size in the range of 70–250 nm and pore size of ~ 8 nm was synthesized using sodium silicate extracted from rice husk at most favourable conditions and adding up of phosphoric acid. The degree of accumulation of the mesoporous particles was extremely reliant on sodium silicate predecessor concentration, solvent and pH. For the characterization of silica powder, various techniques were used such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) and N2 adsorption/desorption, and the morphology of the mesoporous powder was characterized via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The synthesis method adopted was kept green and ecofriendly. The end product silica is a favourable choice in dental composite production.