Journal of Sol-Gel Science and Technology https://doi.org/10.1007/s10971-020-05353-5 REVIEW PAPER: SOL-GEL, HYBRIDS AND SOLUTION CHEMISTRIES Utilization of secondary agricultural products for the preparation of value added silica materials and their important applications: a review Jyoti Singh 1 ● Rajamouli Boddula 1 ● Harishchandra Digambar Jirimali 1 Received: 22 April 2020 / Accepted: 25 June 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Silica and its compounds are widely used in the industries like pharmaceutical, chemical, agricultural, and research sectors. Generally, silica is obtained from natural precursors available in the form of silicates. Extensive use of silica makes it necessary to find the new sources and methods of synthesis. Secondary agricultural products and by-products like rice husk, sugar cane bagasse, corn cabs, wheat straw, rice straw, grasses, and coconut husk contains considerable amount of silica. The methods for the extraction of silica includes burning of materials to make it ash, acid treatment, base treatment, ionic liquids, and sol-gel methods. Among all the methods, sol-gel is an important method of silica synthesis. Highly pure and desirable silica materials can be synthesized by the chemical leaching process, where metallic impurities can be removed by the acid treatment. This review describes the selected secondary agricultural products and their utilization for the value-added silica synthesis. Graphical Abstract Keywords Sol-gel Silica Nano-materials ● Agricultural waste ● Sustainable development ● Catalysis ● Biomedical applications ● Polymer nano-composite Highlights ● Secondary agricultural products and by-products contains considerable amount of silica. ● Simple methods can be utilized for the extraction of silica from agricultural waste. ● Sol-gel process is one of the effective method for the extraction of silica. ● The Extracted silica can be utilized for various important applications. 1 Introduction Silicon dioxide is a widely distributed compound along with the earth’s crust, its most abundant form is known as silicic acid (Si(OH) 4 ). It is having wide applications in the various fields from the basic scientific labs to the large industries. Silicates are the stable complexes of the minerals and some of them are useful as fused silica, quartz, feldspars, fumed, * Harishchandra Digambar Jirimali hdj739@gmail.com 1 Department of Chemistry, Uka Tarsadia University, Maliba Campus, Gopal-Vidya Nagar, Surat, Gujarat 394350, India 1234567890();,: 1234567890();,: