Production and characterization of microporous activated carbons and metallurgical bio-coke from waste shell biomass

To produce activated carbon and bio-coke, palm kernel shells (PKS), walnut shells (WNS) and cashew nut shells (CNS) were carbonized and (or) activated. The activation was conducted using CO₂ in a fixed bed reactor. In the activation of PKS, the influence of CO₂ flow rate on the surface area development was also examined. Meanwhile, to evaluate the suitability of chars obtained from CNS as metallurgical bio-coke, carbonization was carried out in N₂ at temperatures of 700-800 °C. The maximum surface areas of the resultant activated carbons derived from each biomass were about 700-810 m²/g, and all the activated carbons had a microporous nature. At a CO₂ flow rate of 1 NL/min, the activated carbon obtained from PKS showed the highest surface area of 912 m²/g. The char produced from CNS, with its low ash and volatile matter contents and its sufficient compressive strength, demonstrated promising potential as metallurgical bio-coke.