Removal of Pb2+ and Zn2+ from the aqueous solutions by activated carbon prepared from Dates stone

Abstract

The low-cost activated carbon prepared from Date stone, an agricultural solid waste by-product, were prepared by chemical activation with sulphuric acid for the removal of lead and zinc from aqueous solutions has been studied as a function of pH, contact time, metal concentrations and adsorbent concentrations. Adsorption equilibrium was reached after an equilibration time of 60 min and adsorption kinetics data were tested using Lagergren pseudo-first-order and pseudo-second order, the studies showed the adsorption process followed pseudo-second-order rate model. The maximum removal of Pb2+ and Zn2+ is observed at pH 6.0 (94.4%) and 7.0 (93.2%) respectively at initial concentration 20 mg/L. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models. The adsorption capacity q max) calculated from the Langmuir isotherm was 19.64 mg Pb2+/g and 10.41 mg Zn2+/g at an