Adsorption of copper(II) from aqueous solutions on activated carbon prepared from grape bagasse

Abstract

Activated carbons were prepared from grape bagasse by chemical activation using phosphoric acid and the prepared activated carbons were used to remove copper(II) from aqueous solutions. The effects of impregnation ratio (IR) and activation temperature on activated carbon production were investigated. The produced activated carbons were characterized by N2 adsorption, scanning electron microscopy (SEM), Boehm titration and Fourier transform infrared (FTIR) techniques. The highest surface area (1455 m2/g) and total pore volume (0.88 cm3/g) were obtained at a carbonization temperature of 500 °C with an impregnation ratio of 5/1. The resulting activated carbon was used for removal of copper(II) from aqueous solution. The effects of initial pH, temperature and contact time were investigated. The adsorption isotherm studies were performed and the obtained data were analyzed using Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R) equations. The Langmuir and Dubinin–Radushkevich isotherm equations showed better fit for all temperatures and the maximum adsorption capacity of copper(II) was obtained as 43.47 mg/g at 45 °C. Pseudo first order, pseudo second order, Elovich and intraparticle diffusion kinetic models were used in this study to describe the adsorption process. The rate of adsorption was found to conform to the pseudo second-order kinetic model.