There are several methods for the extraction of silica from biomass. Many authors [2,3,4,5], have
suggested that acid preliminary treatment before thermal treatment is a reasonable method for natural
silica extraction. The high purity of silica and low mineral impurity are retrieved by boiling in
hydrochloric solution for 1 h followed by burning in the atmosphere at 650-700 °C for 4 h [3]. By
means of this method, the extracted silica is found in a form of amorphous structure which is the most
reactive form for silylation reaction