Biogenic Silica from Rice Husk Ash - Sustainable Sources for the Synthesis of Value Added Silica

Abstract

Ordered mesoporous silica with two dimensional MCM-41 or three dimensional MCM-48 pore structure are prepared via pseudomorphic transformation. Rice husk ash (RHA) with high purity was used as silica source for the first time. Additionally, the kinetics of pseudomorphic transformation of rice husk ash into MCM-41 was studied. MCM-48 was synthesized by pseudomorphic transformation of preformed MCM-41. The obtained MCM-41 and MCM-48 materials possess high specific surface areas of 1,210 and 815 m2 g- 1, respectively. Both materials are characterized by uniform mesopores and high pore volumes (pore width of 4.1 nm and pore volume of 1.0 cm3 g-1 for MCM-41, whereas MCM-48 exhibits a mean pore width of 3.3 nm and pore volume of 0.75 cm3 g-1). In addition, the preservation of the macroscopic morphology of rice husk ash after pseudomorphic transformation is shown.