Microporous activated carbon from Siris seed pods by microwave-induced KOH activation for metronidazole adsorption

In this study, microwave-assisted KOH activation was adopted for preparation of a microporous activated carbon from an agricultural waste, Siris seed pods. Carbon with high BET surface area of 1824.88 m2/g and 0.782 cm3/g total pore volume has been obtained from these precursors. The influences of radiation time, radiation power, and impregnation ratio on yield and iodine number of prepared carbon have been studied and the best conditions were determined. The sorption mechanisms of a nitroimidazole antibiotic, metronidazole (MNZ), onto such carbon have been investigated. The adsorption data of MNZ were analyzed by Langmuir, Freundlich, and Temkin isotherms and the best correlation was achieved by the Langmuir isotherm with maximum capacity of 196.31 mg/g. The analyses of kinetic data showed that the adsorption of MNZ on prepared carbon follow closely the pseudo-second order model. Results of thermodynamic studies showed endothermic and spontaneous natures of MNZ adsorption under examined conditions.