Efficient and Sustainable Bidentate Amines-Functionalized Resins for Removing Ag, Cu, Pb and Fe from Water.

We evaluate the effectiveness of chelating resins (CR) derived from Merrifield resin (MR) and 1,2-phenylenediamine (PDA), 2,2'-dipyridylamine (DPA), and 2-(aminomethyl)pyridine (AMP) as adsorbent dosimeters for Ag, Cu, Fe, and Pb cations from water under competitive and noncompetitive conditions. MR-PDA, MR-DPA, and MR-AMP were obtained in a 95-97% yield and characterized by IR, fluorescence, and SEM. The ability of CRs as adsorbents was determined by batch and flow procedures. MR-PDA showed a batch adsorption capacity order of Fe (29.8 mg/g) > Ag (2.7 mg/g) > Pb (2.6 mg/g) at pH 3.4. The flow adsorption showed affinity towards the Ag cation at pH 7 (18.4 mg/g) and a reusability of 10 cycles. In MR-DPA, the batch adsorption capacity order was Ag (9.1 mg/g) > Pb (8.2 mg/g) > Cu (3.5 mg/g) at pH 5. The flow adsorption showed affinity to the Cu cation at pH 5 (2.2 mg/g) and a reuse of five cycles. In MR-AMP, the batch adsorption capacity was Ag (17.1 mg/g) at pH 3.4. The flow adsorption showed affinity to the Fe cation at pH 2 (4.3 mg/g) and a reuse of three cycles. The three synthesized and reusable CRs have potential as adsorbents for Ag, Cu, Fe, and Pb cations and showed versatility in metal removal for water treatment.