Separation and Speciation of Iron Ions by Using Colorimetric Hydrogels

In this study, Fe³⁺ ion selective N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine (RH6GAC) monomer was synthesized. Then, p(Acrylamide-co-N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine) (p(AAm-co-RH6GAC)) and p(2-hydroxyethyl- methacrylate-co- N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine) (p(HEMA-co-RH6GAC)) colorimetric hydrogels were synthesized by using acrylamide (AAm) and 2-hydroxyethylmethacrylate (HEMA) as primary monomers. FT-IR, SEM, polymerization yield and swelling characterizations were conducted for the resulting hydrogels. Then, these hydrogels were used in selective absorption of Fe³⁺ ions from aqueous media. The hydrogels, which could absorb Fe³⁺ ions selectively from a mixture of metal ions, were used as column packing material. The solutions containing Fe²⁺ and Fe³⁺ ions at different concentrations were separated at a rate of 97.7 ± 0.7%.