Removal of Pb (II) from aqueous solution by adsorption using activated carbon developed from Apricot stone: equilibrium and kinetic

Activated carbons were developed from Apricot stone, by chemically treating with sulfuric acid. Batch adsorption experiments were performed to find out the effective lead removal at different metal ion concentrations, adsorbent size, and dosage. Adsorption of Pb2+ ion was strongly affected by pH. Apricot stone exhibited the highest lead adsorption capacity at pH 6.0. Isotherms for the adsorption of lead on Apricot stone were evaluated with the Langmuir, Freundlich adsorption isotherm models. The equilibrium data fitted well to the Langmuir and Freundlich isotherm models. Adsorption kinetics data were modeled using the pseudo-first and pseudo-second-order models. The results indicate that the second-order model best describes adsorption kinetic data. The estimated maximum capacities of lead ions adsorbed by Apricot stone activated with sulfuric acid were 21.38 mg g(-1). This high uptake showed Apricot stone activated carbon as among the best adsorbents for Pb(II).