Chemistry and Materials Research www.iiste.org ISSN 2224- 3224 (Print) ISSN 2225- 0956 (Online) Vol.3 No.4, 2013 68 Extraction and characterization of Amorphous Silica from Corn Cob Ash by Sol-Gel Method E. A. Okoronkwo 1* P. E. Imoisili 1, 2 , S.O.O. Olusunle 2 1. Chemistry Department, Federal University of Technology Akure. Ondo State, Nigeria 2. Engineering Materials Development Institute P.M.B. 611, Akure. Ondo state, Nigeria * E-mail of the corresponding author: afamex@yahoo.com Abstract Extraction of amorphous silica from Corn cob Ash (CCA) was carried out in this study. Silica xerogel was produced by dissolving CCA with alkali solution to form sodium silicate solution and lowering the pH to7.0 by adding hydrochloric acid to form silica aquagel followed by drying to form silica xerogel. The silica xerogel was characterized using XRF, XRD and FTIR techniques. Silica and mineral contents of CCA and xerogel were determined by XRF, X-ray diffraction patterns revealed amorphous nature of extracted silica. Fourier transform infrared (FTIR) data indicated the presence of siloxane and silanol groups. Silica yield from CCA was 52.32% while moisture content was 2.89%. Keywords: corn cob ash; amorphous silica; xerogel; aquagel 1. Introduction Silica has been widely used in pharmaceutical products, chromatograph column packing, detergents, adhesives, electronics, dental material, and ceramics. (Brinker and Scherer, 1990; Proctor et al 1995; Sun and Gong, 2001). Silica has also been used as a major precursor for a variety of inorganic and organometallic materials which have applications in synthetic chemistry as catalysts, and in thin films or coatings for electronic and optical materials (Kalapathy, et al 2002). A low energy method to produce pure silica from rice husk ash with 91% extraction yield, has been developed (Kalapathy et al., 2000; Kamath and Proctor, 1998), acid leaching (Chakraverty and Kaleemullah, 1991) and gasification (Luan and Chou, 1990) methods have also been investigated for recovering silica from rice hull. Corn, is a main staple food in Nigeria, with an annual production of 9.4 million tons, The cobs produced from corn are mainly used as manure for agricultural production. (Latif and Rajoka 2001). Silica has been successfully extracted from different agricultural materials like rice husk (Kamath, and Proctor, 1998, Polska and Radzki, 2008; Yalcin and Sevinc 2001; Sidheswaran and Bhat 1996), sugar cane Bagasse (Affandi et al 2009, and Espindola- Gonzalez et al 2010) coffee husk (Espindola-Gonzalez et al 2010) and wheat husk (javed et al 2011). Mohanraj et al (2012), Prepared and characterized nano SiO 2 from corn cob ash by precipitation method. Hence, objective of this work is to extract amorphous silica from corn cob Ash, using the sol gel technique. This method has dual benefit; valuable silica particle at lower cost can be produce with reducing disposal as well as pollution challenges. The prepared amorphous silica has been characterized using XRF, XRD, and FTIR technique. 2. Materials and Methods Corn cob (zea rugosa), was obtained from south western Nigeria, after the harvest seasons, the corn cobs was washed and sun dried. The combustion were carried out at 650 o C for 3 hours at a heating rate of 10 o C/min in a muffle furnace, and left over night to cool in the furnace. 2.1 Silica Extraction Silica was extracted from Corn Cob Ash, (CCA) adapting the method of Kamath and Proctor (1998), 250 ml portions of 1N NaOH were added to 50g CCA samples and boiled in covered 500ml Erlenmeyer flask for 1 h with constant stirring to dissolve the silica and produce a sodium silicate solution. The solutions were filtered through a