The regional bio-wastes available in abundance in India were converted into porous carbon by heat treatment at different temperatures from 650-950℃. The wood retain shapes after pyrolysis though shrinkage occured both in axial and radial directions. The shrinkage in radial direction was found to be more than in axial direction in all woods. The density of woods and chars from these at a given temperature has been found to follow linear relationship. Chars were steam activated at temperature 700-800℃ for different times between 45-240 min. Both the temperature and time of activation with steam has a profound effect on surface area. Chars from softwoods like bagasse and castor oil plant were activated at lower temperature, i.e. 700-750℃ whereas hard wood chars have to be activated at higher temperature around 800℃. The morphology of wood as well as of chars has been studied by SEM. The comparison of the two showed that the nature of porosity in chars depends on precursor morphology, nature and physical state of wood and presence of inorganic compounds in the wood. Hard wood results in cross inter connected pores while softwood leads to fibriller structure. The present studies show that activated carbon with reasonably good surface area (~1000m2/gm) can be prepared from soft wood bio-wastes like bagasse and castor oil plant, while surface area ~1370m2/gm was achieved from hard wood bio waste of pine wood.

• Satish M. Manocha(Department of Materials Science, Sardar Patel University)
• Vanraj B. Chauhan(Department of Materials Science, Sardar Patel University)
• L.M. Manocha(Department of Materials Science, Sardar Patel University)