Application of response surface methodology ( RSM) for optimization of Cu2+, Cd2+, Ni2+, Pb2+, Fe2+, and Zn2+ removal from aqueous solution using microwaved olive stone activated carbon.

BACKGROUND The efficiencies of removal of Cu²⁺, Cd²⁺, Ni²⁺, Pb²⁺, Fe²⁺, and Zn²⁺ from aqueous solution with olive stone activated carbon ( OSAC) were investigated in this work. A central composite design ( CCD) method was used to optimize the preparation of OSAC using microwave assisted potassium hydroxide. RESULTS The optimum conditions obtained were 565 W radiation power, 7 min radiation time, and 1.87 impregnation ratio. This resulted in 98.55% removal of Cu²⁺, 95.32% of Cd²⁺, 98.19% of Ni²⁺ 98.83% of Pb²⁺, 99.32% of Fe²⁺, 98.36% of Zn²⁺, and 85.15% of OSAC yield. The surface characteristics of the AC prepared under optimized conditions were examined by pore structure analysis, scanning electron microscopy ( SEM) and Fourier transform infrared spectroscopy ( FT-IR). The BET surface area, total pore volume and average pore diameter of the prepared AC were 1280.71 m² g⁻¹, 0.604 cm³ g⁻¹ and 4.63 nm, respectively. The equilibrium data of the adsorption was well fitted to the Langmuir equation and the highest value of adsorption capacity ( Q) on the OSAC was found for Fe²⁺ (62.50 mg g⁻¹), followed by Pb²⁺ (23.47 mg g⁻¹), Cu²⁺ (22.73 mg g⁻¹), Zn²⁺ (15.08 mg g⁻¹), Ni²⁺ (12.00 mg g⁻¹), and Zn²⁺ (11.72 mg g⁻¹). CONCLUSIONS OSAC prepared by microwaves can be used for the removal of metals from contaminated wastewater. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]