A comprehensive evaluation of inherent properties and applications of nano-biochar prepared from different methods and feedstocks

Biochar a carbonaceous solid easily scale up into nano biochar (N-BC) by various physical and chemical activation methods to acquire the suitable physicochemical and surface properties wide applicability in a different field. The focus of this review is to provide comprehensive and up-to-date information on the production method and inherent properties of N-BC. This review thoroughly summarized the production, techno-economic advantages, and disadvantages of different methods of N-BC. The composition, size, morphology, surface area, and functional groups of N-BC prepared from different methods and feedstocks have been compared. The mechanism of N-BC production methods and the relation between the properties of N-BC and the process used for production are discussed. The review gives insight on the environmental application of N-BC as removal of contaminants, sustained release of allopathic compounds, enzyme immobilization, fuel additives, photocatalyst, and filler for reinforcement comprehensively and comparison with other nanomaterial and bulk biochar (B-BC). This review provides state-of-art knowledge about N-BC production, properties, and applications and the knowledge gap that need to be addressed in future experiments.