Synthesis and Characterization of Polystyrene-Supported Piperazine-Substituted Triazoles by CuAAC and First Evaluation for Metal Ion Extraction

The goal of this work was to synthesize substituted polystyrene for metal extraction and/or depollution by introduction of substituted piperazines as chelatants starting from Merrifield polymer. After transformation of Merrifield’s resin in azidomethyl polystyrene, click-chemistry using copper (I)-catalyzed Huisgen’s reaction (CuAAC) was performed to prepare different polymers grafted with 1,4-triazoles bearing the piperazines, containing an alkyne as the other counterpart in the CuAAC. The polymers were then first tested for their efficiency to remove various metal ions from neutral aqueous solutions (Fe(3+), Ni(2+), Cu(2+), Zn(2+) and Pb(2+)). The polymers were found to extract Ni(2+) and Zn(2+) with low efficiencies ≤40%. For Fe(3+) and Cu(2+), the average extraction was around 80%, and for Pb(2+) around 50%. The global selectivity for these polymers was found to be in the order of Fe(3+) ≥ Cu(2+) > Pb(2+) >> Ni(2+) > Zn(2+).