Development of activated carbon from KOH activation of pre-carbonized chickpea peel residue and its performance for removal of synthetic dye from drinking water

In this study, we report the synthesis of activated carbon from chickpea ( Cicer arietinum ) peel waste via carbonization and KOH chemical activation method. Porous texture and elemental analysis were analyzed using scanning electron microscopy, and surface functional groups were analyzed using Fourier transform infrared spectroscopy. The effect of pre-carbonized chickpea peel/KOH ratio and activation temperature on dye removal kinetics was investigated. The peels pre-carbonized at 400℃ and activated with KOH ratio of 1:3 at 800 °C resulted in a porous carbon with a specific surface area of 917 m 2 /g and demonstrated to be excellent adsorbent for methylene blue dye. The adsorption kinetics data was well described by the pseudo-second-order kinetic model and equilibrium data was favorably fitted with the Langmuir isotherm model. The maximum adsorption capacity was found to be 448.43 mg/g and 523.56 mg/g at 25 °C and 35 °C, respectively, at neutral pH. These findings provide the feasibility of chickpea peel waste to be used as a low-cost and sustainable precursor for the preparation of activated carbon material to be used in drinking water purification.