Synthetic Approach to Rice Waste-Derived Carbon-Based Nanomaterials and Their Applications

The utilization of biomass waste to produce valuable products has extraordinary advantages as far as both the economy and climate are concerned, which have become particularly significant lately. The large-scale manufacturing of agricultural waste, mainly rice by-products (rice husk, rice straw, and rice bran), empowers them to be the most broadly examined biomasses as they contain lignin, cellulose, and hemicellulose. Rice waste was first used to incorporate bulk materials, while the manufacturing of versatile nanostructures from rice waste at low cost has been developed in recent years and attracts much consideration nowadays. Carbon-based nanomaterials including graphene, carbon nanotubes, carbon dots, fullerenes, and carbon nanofibers have tremendous potential in climate and energy-related applications. Various methods have been reported to synthesize high-value carbon nanomaterials, but the use of green technology for the synthesis of carbon nanomaterials is most common nowadays because of the abundant availability of the starting precursor, non-toxicity, low fabrication cost, ease of modification, and eco-friendly nature; therefore, reusing low-value biomass waste for the processing of renewable materials to fabricate high-value products is remarkable. Carbon nanomaterials derived from rice waste have broad applications in various disciplines owing to their distinctive physicochemical, electrical, optical, mechanical, thermal, and enhanced biocompatibility properties. The main objective of this review and basic criteria of selecting examples and explanations is to highlight the green routes for the synthesis of carbon nanomaterials—i.e., graphene, carbon nanotubes, and carbon dots—from rice biomass waste, and their extensive applications in biomedical research (bio-imaging), environmental (water remediation), and energy-related (electrodes for supercapacitors, Li-ion battery, fuel cells, and solar cells) applications. This review summarizes recent advancements, challenges, and trends for rice waste obtained from renewable resources for utilization in the fabrication of versatile carbon-based nanomaterials.