Silica Nanoparticles Synthesized from Maize Cob using Modified Sol-Gel Method

Abstract

Silica has found applications in many industries. Its production from agricultural wastes has been reported but with marked agglomeration of the final product. This work investigated production of silica nanoparticles from maize cob and effect of sol-gel modification with ethylene glycol on degree of agglomeration was also examined. This work also explored the effects of acid pre/post calcination treatments of the maize cob. Maize cob was treated with HCl prior to and after calcination. Using sol-gel method, silica was produced from both untreated and treated maize cobs. Ethylene glycol was also added to sodium silicate prior to precipitation of silica gel for modification of the conventional sol-gel procedure. The results showed that acid treatments affect the purity of silica nanoparticles. Ethylene glycol was observed to reduce degree of agglomeration in silica nanoparticles production from agricultural wastes. Silica nanoparticles of sizes between 5 and 50 nm were successfully synthesized.

Keywords: Agricultural Wastes, Maize cob, Amorphous silica, Agglomeration, Sol-gel, Acid pre-treatment.