Optimum features of wood-based biochars: A characterization study

Research on biochar is in current trend due to its vast applicability in various fields and has garnered everyone's attention due to its unique physicochemical properties and surface structures. The favourable properties of biochar include its high surface area and porosity and ability to adsorb various compounds, including nutrients, organic contaminants, and some gases. Physical and chemical properties of biochars are dictated by the feedstock and process parameters such as pyrolysis or gasification temperature, conversion technology and pre- and post-treatment processes, if any, which vary widely across biochars produced from different biomasses. This study focuses on wood biomasses, neem and old furniture waste wood (a mixture of different woods), one natural and the other, waste, to characterise their physical and chemical properties that can signify their relevant environmental applications. Physical properties such as surface area, morphology and surface characteristics and chemical properties like organic matter and organic carbon contents, pH, and electrical conductivity, carbon, nitrogen and hydrogen (CHN) elemental composition have been analysed in this study. In addition, raw biomass analysis is also done to understand the behaviour of the biomass in producing biochar. Also, thermogravimetric analysis has been performed using three models to study the effect of process parameters on biochars. A wide range of fixed carbon (11.8–35.73%), volatile matter (58.25–82.17%), and ash contents (1.98–4.06%) were observed among tested biochars. The H/C ratio accounts for the aromaticity of the material and with temperature, the ratio decreases. Lower H/C ratios demonstrate increased aromaticity caused by pyrolysis and therefore indicate higher stability of the material than the initial feedstock. This study will pave the way for understanding the behaviour of wood biochar as a type and its efficiency as a material in utilisation as an adsorbent, in filter media, remediating water and soil amelioration.