Synthesis and Ion-Binding Properties of Polymeric Pseudocrown Ethers. III. Ion-Binding Studies

ABSTRACT

An ion-induced templatization strategy was used to prepare crosslinked polymeric pseudocrown ethers (PCEs) in situ during a one-step free-radical polymerization. These studies bring to a conclusion the fundamental studies on the templatization process reported in the first two papers of this series. For the PCEs, with nickel as the templating ion and hydroxyethyl methacrylate as the monovinyl comonomer, the ion-binding studies revealed a significant enhancement in the ion-binding capacity associated with the inclusion of the template ion during synthesis. For example, a PCE synthesized with a monomer-to-solvent ratio of 20/80 exhibited an ion-binding capacity that was 7.5 times higher than a control polymer produced under identical conditions except for the absence of the template cations. A PCE synthesized with a monomer-to-solvent ratio of 20/80 exhibited a capacity of 0.3 mg/g polymer for Ni²⁺ cations. Finally, it was observed that the column could be fully regenerated by elution with a small volume of a 1 M HCL solution at 60°C, resulting in the recovery of the bound ions as a concentrated solution.