Removal of metals by Fe3O4 loaded activated carbon prepared from plum stone (Prunus nigra): Kinetics and modelling study

This study investigates the adsorption of Cu(II) and Pb(II) ions onto magnetic-plum stone activated carbon (m-PSAC). Plum stone-activated carbon (PSAC) was produced by chemical activation of plum stone (PS) with phosphoric acid (H3PO4\) in N-2\ inert atmosphere. The effects of activator ratio, activation temperature, and impregnation temperature were examined. m-PSAC was prepared by co-precipitation method which is a combination of PSAC with Fe2+:Fe3+ salts. The prepared m-PSAC was characterized by scanning electron microscopy (SEM) and Fourier Transform infrared spectrophotometer (FT-IR). Then m-PSAC was used for the removal of Cu(II) and Pb(II) ions from aqueous solutions. The effects of initial pH, the amount of m-PSAC, temperature, contact time, and the initial concentration of Cu(II) and Pb(II) were investigated during the equilibrium and kinetics studies. Adsorption isotherms for the Cu(II) and Pb(II) on m-PSAC was determined and correlated with Langmuir, Freundlich, Scatchard and D-R isotherm equations. The adsorption data showed that adsorption of Cu(II) and Pb(II) was fitted by Langmuir isotherm model and pseudo-second-order kinetics model. Under the optimized conditions, maximum adsorption capacities of Cu(II) and Pb(II) ions determined by Langmuir model were enhanced 48.31 and 80.65 mg/g, respectively. Thermodynamic parameters such as Delta G degrees, Delta H degrees, Delta S degrees, E-a were calculated and the interaction of metals with m-PSAC was found to be exothermic and spontaneous in nature. (C) 2017 Elsevier B.V. All rights reserved.