Peptidyl Resins as Efficient Adsorbents for Ag+ and Cd2+ Removal from Aqueous Solutions

Heavy metal contamination of water by cadmium (Cd2+) and silver (Ag+) represents a significant environmental concern due to their toxicity and persistence. In this study, peptide-functionalized resins were evaluated as bio-inspired adsorbent materials for metal removal from aqueous solutions. Glycine-based and histidine-containing peptide sequences were synthesized via solid-phase peptide synthesis and immobilized onto Wang and Rink amide resins, with and without N-terminal acetylation. Adsorption capacity (Q, mg g−1) was determined for each material. The results showed that adsorption performance strongly depends on both peptide structure and metal type. Higher adsorption capacities were consistently observed for Cd2+ (up to 7.9 mg g−1) compared to Ag+ (up to 2.4 mg g−1). Interestingly, histidine-containing resins exhibited superior performance, likely due to the presence of imidazole groups that enhance metal coordination. In contrast, the influence of resin type and N-terminal acetylation was less consistent, suggesting a secondary role of these factors. Overall, the findings provide an initial screening or proof-of-concept for peptide-functionalized resins and highlight the potential of these peptidyl resins as effective adsorbent materials for the removal of heavy metals from aqueous environments.