Fabrication of nano-silica from agricultural residue and their application

Agricultural residues are used as sources to synthesize biogenic silica. It is renewable, environment friendly, and economical resource of high silica content. The biosilica obtained from agricultural wastes is claimed to be cheap and cost-effective substrate for silicon chip, silica gels, catalysts, silica-carbon composite, construction materials, battery materials, energy storage/capacitor, zeolites, carbon capture and cosmetic additive. The extensive uses of silica nanoparticles in various industrial and domestic products have led to the development of silica extraction and purification processes from various agricultural residues. The agricultural residues/lignocellulosic biomass (e.g., wheat straw, rice straw, bagasse, rice husk, etc.) are enriched with large quantity of biosilica materials. This chapter elaborates various silica extraction methodologies, like thermal and chemical processes. It also provides guidelines to new, efficient, and rapid microwave-assisted process for silica production. Thus, the commercial production of silica would not only support the protection of environmental pollution, due to large quantity of agricultural waste being burnt, but also provide additional income and enhance the sustainable economic growth of farmers of the developing countries.