An investigation of adsorption of lead(II) and copper(II) ions by water-insoluble starch graft copolymers

An investigation was undertaken regarding the adsorption of lead(II) and copper(II) ions from aqueous solutions by water-insoluble starch graft copolymers containing tertiary amine groups, which were prepared by grafting dimethylaminoethyl methacrylate onto commercial crosslinked starch. The effects of treatment time, initial pH of the solution, metal ion concentration, and grafting percentage of the starch graft copolymers on the adsorption were considered. Two hour of adsorption time was found to be sufficient for reaching the adsorption equilibrium, and the adsorption equilibrium data correlate well with the Langmuir isotherm equation. For the starch graft copolymer with the grafting percentage of 60%, the saturation adsorption capacity evaluated from Langmuir isotherms toward lead(II) and copper(II) ions was found to be 2.09 and 2.12 mmol g−1 (dry weight), respectively.