A comprehensive review on biochar, with a particular focus on nano properties and applications

Abstract

Biochar is a carbon-based material obtained from the thermal decomposition of a wide range of organic biomass. Its earliest uses date back to ancient agricultural practices across the world, where it was used to enrich the soil. However, it has recently become an area of interest due to its potential in environmental remediation and industrial applications. This article provides a description of the main production techniques and their advantages. It offers an overview of the physical and chemical properties, including surface area, porosity, and elemental composition, as well as the factors that influence them. It also reviews different activation methods used to enhance biochar's properties, depending on its intended use. It discusses the applications that are now in use, such as its role in environmental remediation, energy production, and as a catalyst, analysing the possible future applications as well. All of this is realized with a careful examination of nanobiochar, investigating how certain properties, such as surface area and porosity, differ at nanoscale. Materials with a size of less than one hundred nanometers are classified as "nano" and tend to behave differently due to the significant increase in surface-to-volume ratio, which leads to the observation of quantum confinement effects.