Adsorption of Cd ions from aqueous solutions by iron modified pomegranate peel carbons: kinetic and thermodynamic studies

The experimental conditions for preparation of pomegranate peel carbon and Fe(III) modified pomegranate peel carbon were studied. The effects of main experimental parameters on carbon preparation such as carbonization time, carbonization temperature and Fe(III) impregnation ratio in pomegranate peel were investigated. The prepared carbons in various conditions were characterized by consideration of the production yield, ash content, iodine number, pH of zero point charge and their ability for adsorption of methylene blue. After preparation of carbons, their efficiency for removal of Cd²⁺ species from aqueous solution was investigated. The effect of experimental parameters such as Cd²⁺ initial concentration, pH of solution and contact time was studied by batch adsorption experiments. The fitting of experimental data in thermodynamic isotherms matched the linear results with Langmuir and Freundlich isotherms. The adsorption capacity for Cd²⁺ species on Fe(III) modified pomegranate peel carbon was 22.72 mg/g and the adsorption kinetic presented the pseudo-second-order kinetic model.