Heavy-Metal Ion Extracting Agents Based on Crosslinked Polyethylenimine

New porous polymer materials based on crosslinked highly branched polyethylenimine (PEI) are synthesized. Epichlorohydrin, diethylene glycol diglycidyl ether, and chloroacetic acid diesters with ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol-400 are used as crosslinking agents. The PEI/crosslinking agent ratio and means of polymerization, which substantially affect the water uptake of the products, are varied. It is shown that these materials exhibit high sorption activity with respect to metal cations that form complexes with amino groups of PEI: up to 172, 116, and 106 mg/g for copper(II), cobalt(II), and nickel(II), respectively, in an acetate buffer solution at a pH 5.