The untreated and pretreated D.fir samples were pyrolysed in an auger screw driven reactor. Briefly, about half a kilogram of bone dry biomass was fed through the hopper and pyrolysed at a temperature of 500 ° C. residence time of 1 min. and carrier gas flow rate of (Nz) of 20L / min. A slight negative pressure was maintained inside the pyrolytic vapours.The produced biochar was collected in a of condensers.