Adsorption of Ni2+ from aqueous solutions by novel polyethyleneimine‐attached poly(p‐chloromethylstyrene) beads

In this study Ni²⁺ 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 m²/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 Ni²⁺ 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 HNO₃ with higher effectiveness. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2467–2473, 2002