Novel fluorescent hydrogel for the adsorption and detection of Fe (III)

A novel PNIPAAm-CD hydrogel with good adsorption property and stable fluorescence detection for Fe3+ was prepared by copolymerizing PCDs with NIPAAm monomers. As a fluorescence probe, carbon quantum dots (CDs) were modified by glycidyl methacrylate (GMA) to obtain PCDs, which had double bond and could react with N-isopropyl acrylamide to form hydrogel. The functionalization of the amine groups on the surface of the PCDs enables PNIPAAm-CD hydrogel also exhibits photoluminescence behavior. In addition, the PNIPAAm-CD hydrogels stably shows higher adsorption performance for Fe3+ than the pure PNIPAAm hydrogel. The honeycomb PNIPAAm-CD hydrogel had a good quenching response to metallic iron ions, and the detection limit was as low as 0.27 μM in the range of 1μM～1mM. The results of adsorption isotherms and adsorption kinetics showed that the adsorption procedure of metal ions conforms to the pseudo-second-order model and langmuir model, respectively. The effective detection and the high adsorption of PNIPAAm-CD hydrogel for Fe3+ make it an effective portable platform potential, which has the dual functions of visual detection and adsorption of Fe3+.