Ion-imprinted polymers as useful modifiers of sorption properties of activated carbon for Co(II) and Pb(II) removal from aqueous solutions

Heavy metal contamination in water remains a major challenge for environmental protection and public health, creating demand for sorbents that are both efficient and economically viable. To address this need, ion‑imprinted polymers (IIPs) were synthesized using 4‑vinylpyridine (4‑VP), methacrylic acid (MAA), and ethylene glycol dimethacrylate (EGDMA) with Co(II) or Pb(II) as templates, and subsequently blended with DT0 activated carbon (AC) to produce low‑cost composite sorbents with enhanced selectivity. Six IIP–AC and NIP–AC composites were prepared and characterized using FT‑IR, SEM, and adsorption studies. The best-performing materials achieved sorption capacities of 52.97 mg/g for Co(II) and 41.70 mg/g for Pb(II), representing more than a fourfold improvement over unmodified carbon. Isotherm modelling indicated favourable adsorption behaviour, with the Freundlich and Dubinin–Radushkevich models providing the best fits. Thermodynamic parameters suggested that the adsorption process was spontaneous and energetically favourable. Kinetic analyses, demanded dividing the results for the AC and polymer phases, showed that particle diffusion dominated in the carbon matrix, while surface‑controlled processes were more relevant for the polymer domains. The composites also exhibited clear template‑oriented selectivity in multielement solutions, confirming their ability to discriminate between competing ions. Additionally, the materials maintained most of their sorption capacity over five regeneration cycles, demonstrating good operational stability. Overall, the results show that IIP‑functionalized activated carbon composites offer a practical and cost‑effective approach for selective heavy‑metal removal in scalable water‑treatment systems. • Novel composite materials developed for selective environmental remediation • Low-cost activated carbon enhanced with selective polymeric modifiers • Ion-imprinted polymers improve heavy metal removal from aqueous solutions • Adsorption driven by tailored cavities and functional group interactions