Abstract In this study four kinds of biochars were prepared from the KOH modified biomass. As carbon precursors there was used sawdust following trees: oak, hornbeam, apple and cherry. The physicochemical properties materials characterized by N 2 adsorption, scanning electron microscopy, thermal analysis (TG, DTG DTA), infrared spectroscopy, Boehm’s titration method. Moreover, pH pzc (the point...