Nanoporous activated carbon prepared from karanj (Pongamia pinnata) fruit hulls for methylene blue adsorption

Abstract

In this study, karanj (Pongamia pinnata) fruit hulls were used as a precursor to prepare low-cost activated carbon with a large surface area through KOH activation. The prepared activated carbon (KFHAC) was characterized through pore structural analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. KFHAC presents a BET surface area of 828.30 m2/g, a micropore volume of 0.36 cm3/g, and an average pore size of 19.92 Å The adsorption performance of KFHAC was evaluated using methylene blue (MB) as the model adsorbate. Adsorption experiments indicated that the pseudo-second-order kinetic and Langmuir adsorption isotherm models can accurately describe the adsorption process. The maximum adsorption capacities (qm) of MB were 154.8, 203.4, and 239.4 mg/g at 30 °C, 40 °C, and 50 °C, respectively. This study indicates that karanj fruit hull is a promising precursor for the production of low-cost and efficient activated carbon with a large surface area.