Isotherm and kinetic studies of adsorption of methylene blue using activated carbon from ackee apple pods

Abstract

Activated carbons of ackee apple pods were prepared at 400 °C (ZAc-400) and 500 °C (ZAc-500). The surface area and pore volume for ZAc-500 are 812.79 m2/g and 0.387 cm3/g as compared with ZAc-400 of 321.01 m2/g and 0.15 cm3/g respectively. Consequently, ZAc-500 showed better physicochemical properties and a more porous structure than ZAc-400. The presence of -OH, -CH, C=C and C-O were observed on the surfaces of both ZAc-400 and ZAc-500. ZAc-500 performed better than ZAc-400 for the removal of methylene blue (MB). The MB adsorption onto ZAc-400 and ZAc-500 was best described by the Langmuir isotherm with R2 ≥ 0.91 and pseudo-second-order kinetic models with closed values of qe, exp and qe, cal (49.96 and 50.2 for ZAc-500 and 48.99 and 51.2 for ZAc-400 respectively). Ackee apple pod is a potential agricultural waste for the production of activated carbon and the treatment of dye-laden industrial effluents.