Synthesis of Silica from Rice Husk by Sol-Gel Method
Nurdi Setyawan1, Hoerudin1, and Sri Yuliani1

1Indonesian Center for Agricultural Postharvest Research and Development
Jl. Tentara Pelajar No.12, Kampus Penelitian Pertanian Cimanggu, Bogor, West Java, Indonesia

Email: setyawan.nurdi[at]gmail.com

Abstract

Rice husk is an agricultural by-product abundantly available and not optimally utilized yet in Indonesia. The waste contains silica able to substitute natural silica for various purposes. Extraction of silica from rice husk (RH) has been done using sol-gel method without involving high energy. Extraction was done with KOH at concentrations of 7, 10 and 13 percent for 90, 120, and 150 min. These processes resulted in silica (SiO2) 81.99 - 95.34 percent and yield ranged from 7.60 - 9.75 percent. The minimum concentration of KOH could produce the maximum yield of silica. Characterization by XRD showed that the silica has the same pattern with that of commercial product and it was categorized as amorphous silica indicated with the broad peaks at 2 theta = 22 degrees. An amorphous silica with purity above 95 percent was produced from rice husk by KOH 7 percent at 120 min. The process condition resulted in high reactivity and a high BET surface area. Washing process needs to be intensified to improve the purity of silica.

Keywords: synthesis, silica, rice husk, sol-gel method

Topic: WASTE AND ENVIRONMENTAL MANAGEMENT