Optimization of Activated Carbons Prepared from Parinari macrophylla Shells

Abstract

Plant matter constitutes an important source for producing carbonaceous materials. This work deals with the preparation of active carbons from shells of Parinari macrophylla (agricultural waste in Niger). Physical, chemical and mixed activations are considered. Several parameters of preparation are optimized, as the nature of the activation gas (N2 or CO2, dry and wet), the concentration of the activating agent (H3PO4), the time of impregnation and the pyrolysis temperature program. The active carbons are characterized through their iodine numbers, their specific surface areas and their porous volumes. Active carbons, produced from shells of Parinari macrophylla display iodine numbers up to 599 mg I2/g and specific surface areas up to 727 m2/g. They also show microporous characteristics, with a mean pore diameter, usually, lower than 20 Å and a microporous surface percentage up to 88.7% and a microporous volume percentage up to 82.1%. The microporosity is far more developed for the active carbons produced by chemical activation.