Biochar from Wood Waste: Textural and Structural Properties Depending on Production Method

Biochar is a carbonaceous product from biomass obtained by heat treatment of organic materials such as wood, by-products of wood processing, and plant residues. Biochar can be obtained as a result of thermal processing, which can be divided into three main processes: pyrolysis, torrefaction, and hydrothermal carbonization. The resulting biochar has different composition, structural and textural properties, strength, etc. Despite of numerous studies, the investigation of biochar production and properties are of great interest. Modification of carbonaceous products obtained from biomass is one of the actual tasks to produce the tailor-made materials. This article presents a comparison of the characteristics of biochar obtained by three methods: pyrolysis, torrefaction, and hydrothermal carbonization. Another task was the evaluation of the modifier addition to biochar to form materials with higher surface area and abrasion resistance for catalyst applications. The biochar obtained by the torrefaction from different lignocellulosic feedstock (hydrolysed and non-hydrolysed pine and birch sawdust) was found to have the highest carbonization degree, and the highest specific surface area. It was found that the additional modification of biochar with silica provides an increase its abrasion resistance, and higher porosity that allows the material obtained to be used for different purposes (as filler and binder for the construction materials, catalyst support etc.).