Rice Husk at a Glance: From Agro-Industrial to Modern Applications

Excessive waste production has led to the concept of a circular bioeconomy to deliver valuable by-products and improve environmental sustainability. The annual worldwide rice production accounts for more than 750 million tons of grain and 150 million tons of husk. Rice husk (RH) contains valuable biomaterials with extensive applications in various fields. The proportions of each component depend primarily on rice genotype, soil chemistry, and climatic conditions. RH and its derivatives, including ash, biochar, hydrochar, and activated carbon have been placed foreground of applications in agriculture and other industries. While the investigation on RH's compositions, microstructures, and by-products has been done copiously, owing to its unique features, it is still an open-ended area with enormous scope for innovation, research, and technology. Here, we reviewed the latest applications of RH and its derivatives, including fuel and other energy resources, construction materials, pharmacy, medicine, and nanobiotechnology to keep this versatile biomaterial in the spotlight.