Adsorption of Ni 2+ from aqueous solutions by novel polyethyleneimine‐attached poly( p ‐chloromethylstyrene) beads

In this study Ni 2+ adsorption properties of polyethyleneimine (PEI)‐attached poly( p ‐chloromethylstyrene) (PCMS) beads were investigated. Spherical beads with an average size of 186 μm were obtained by the suspension polymerization of p ‐chloromethylstyrene conducted in an aqueous dispersion medium. Owing to the reasonably rough character of the bead surface, PCMS beads had a specific surface area of 14.1 m 2 /g. PEI chains could be covalently attached onto the PCMS beads with equilibrium binding capacities up to 208 mg PEI/g beads, via a direct chemical reaction between the amine and chloro‐methyl groups. After PEI adsorption with 10% (w/w) initial PEI concentration, free amino content of PEI‐attached PCMS beads was determined as 0.91 mEq/g. PEI‐attached PCMS beads were utilized as adsorbents in the adsorption/desorption of Ni 2+ ions from synthetic solutions. The adsorption process was fast; 90% of adsorption occurred within 90 min, and equilibrium was reached at around 2 h. Adsorption capacity was obtained to be 78.2 mg/g at a pH of about 6.0. The chelating beads can be easily regenerated by 0.1 M HNO 3 with higher effectiveness. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2467–2473, 2002