Novel polyamidoamine‐based hydrogel with an innovative molecular architecture as a Co2+‐, Ni2+‐, and Cu2+‐sorbing material: Cyclovoltammetry and extended X‐ray absorption fine structure studies

An amphoteric polyamidoamine (PAA)‐based hydrogel, named INT‐PAA1, with a novel molecular architecture was prepared and studied as a Co²⁺‐, Ni²⁺‐, and Cu²⁺‐sorbing material. This hydrogel was obtained by the synthesis of a PAA in the presence of a second presynthesized PAA carrying many primary amino groups as side substituents, which acted as a macromolecular crosslinking agent. Therefore, it had an intersegmented structure. INT‐PAA1 exhibited a remarkable sorption capacity and sorption rate for Co²⁺, Ni²⁺, and Cu²⁺ that were advantageously in situ monitored by cyclic voltammetry. An extended X‐ray absorption fine structure spectroscopy characterization of the Co²⁺/INT‐PAA1 complex was also performed. The very fast and quantitative metal‐ion uptake, made apparent by an intense coloring of the hydrogel, showed remarkable potential for environmental applications such as heavy‐metal detection, recovery, and elimination. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2316–2327, 2006