Extraction of Silica Content from the Cymbopogan citratus (Lemon Grass) and Its Performance as Reinforcement for Polymers

Silica is widely used as sources for adsorption materials, medical additives and fillers in composite and rubber industries. The manufacturing process of commercial silica use in various industries is very expensive and energy extensive. Therefore, agricultural waste material such as lemon grass is seen as a potential alternative silica sources for replacement of commercial silica which is currently available in the industry. In this research, a simple method based on the acid leaching treatment with hydrochloric acid (HCl) was developed to produce purified silica from lemon grass, followed by thermal combustion at 600 degrees C. Acid leaching temperatures of 33, 50, 80 and 110 degrees C were used. The silica content, shape and texture of the lemon grass ash was characterized using scanning electron microcopy-energy-dispersive X-ray (SEM-EDX) analysis. The SEM analysis indicated the presence of tubular-shaped porous aggregates, spherical and fibrous shapes of untreated and treated lemon grass at 33 degrees C to 110 degrees C. The highest silica content recorded was 73.46% for lemon grass treated at the highest leaching temperature of 110 degrees C. The thermal stability of lemon grass ash was examined by using a thermogravimetric analysis (TGA) instrument. The TGA analysis shows that the untreated and treated lemon grass ash start to decompose at lower temperature (90 to 100 degrees C). Lemon grass treated at the highest leaching temperature 110 degrees C exhibit the highest thermal stability.