Single and binary adsorption of some heavy metal ions from aqueous solutions by activated carbon derived from olive stones

In the present work, activated carbon synthesized from olive stones was used for heavy metal ions (Cu(II), Ni(II), and Pb(II)) removal in single and binary aqueous solutions. The effect of initial solution pH was studied. The equilibrium isotherms for single systems were evaluated in terms of maximum adsorption capacity and adsorption affinity by the application of Langmuir model. Metal ions adsorption increases in the following order: Pb(II) > Ni(II) ≥ Cu(II). The examination of binary adsorption systems: Cu–Ni and Cu–Pb shows that the affinity of copper on the activated carbon surface was strongly dependent on initial concentration of nickel and lead. Copper adsorption was found to increase in the presence of nickel and to decrease in the presence of lead.