Production of Silica from Agricultural Waste

Abstract

The most common generated waste synthesized is rice husk and palm ash, which shown high silica contain as 90-98% and 45- 50%, in respectively [1,2]. Silica produced from these wastes were synthesized mainly using acid leaching treatment. In this study, we focused on the synthesized of other sources silica through sol-gel method. The source such as sugarcane bagasse, corn cob, bamboo stem, and bamboo leaf, till now is still not widely explored, hence become the basis to study the amount of silica that been extracted. Within the scope of study, it shown that several factors play a vital role in determining the silica content of the material, including the species of source material, soil content of source material, maturation etc. Sol-gel synthesis is one of the most common method of converting ash into silica gel. In this process, silica was synthesized from ash through simultaneous hydrolysis and condensation reaction where a sol of sodium silicate, silicon alkoxide or halide gels converted into a polymeric network of gel [3]. The synthesis of silica using this method, lead to silica precipitation under certain conditions like restriction of gel growth that involved coagulation and precipitation step during its preparation [4]. Silica gel synthesize through this method also known as xerogel. The purification and drying produce silica in amorphous powder form that remove any impurities or organic matter that usually contain in waste [1].