Synthesis and characterization of a novel bispyridylmethylamine-based copolymer for Co(II) chelation

Cobalt is a critical element used in several industries with limited natural sources. This study addresses the challenge of its recovery from solutions containing other transition metals, by synthesizing a novel chelating resin based on an original monomer, bis-AMP-MMA. bis-AMP-MMA was prepared through the introduction of a polymerizable methacrylic group into bis(2-pyridylmethyl)amine. The bis-AMP-MMA monomer was proven to form stable 1:1 and 1:2 stoichiometry complexes with Co(II) ions, indicating strong potential for cobalt recovery. To further assess its applicability, bis-AMP-MMA was copolymerized with ethylene glycol dimethacrylate (EGDMA) to prepare an adsorbent highly crosslinked resin, poly(bis-AMP-MMA- co -EGDMA). The new resin was characterized by FTIR, 13 C CPMAS NMR, SEM and BET method. It showed a surface area of 153.9 m 2 /g, and demonstrated a maximum Co(II) adsorption capacity, q e , of 54.0 mg/g at pH 6.5. It also exhibited selectivity for Co(II) over Ni(II), Cd(II), and Mn(II) ions, with selectivity coefficients, k , between 1.13 and 2.09. Additionally, the resin showed good reusability, maintaining 93 % of its efficiency after the first cycle and 65 % after five cycles. • A novel chelating monomer based on bis(2-pyridylmethyl)amine was synthetised. • The complex formation between the new monomer and Co(II) ions was studied in situ . • The new monomer exhibited stronger Co(II) chelation than bis(2-pyridylmethyl)amine. • The enhanced chelation properties likely result from the additional carbonyl group. • A new adsorbent with good Co(II) adsorption performance was produced and tested.