<p>Adsorbents incorporating the natural polysaccharide chitin show significant potential for heavy metal enrichment. However, existing chitin hydrogels suffer from poor recyclability and low adsorption capacity, limiting their practical applications. To address these limitations, an interpenetrating network hydrogel (TOChNs-G) for the adsorption of heavy metal ions was prepared by cross-linking TEMPO-oxidized chitin nanofibers-composite gelatin with glutaraldehyde supramolecules. The morphology and graft modification of chitin were evaluated by TEM, XRD, and ATR-FTIR. The microstructure and mechanical strength of the hydrogel were characterized by SEM, rotational rheometer, and tensile testing. The adsorption capacities for the heavy metal ions Fe³⁺, Cr³⁺, Cu²⁺, and Mn²⁺ were investigated, yielding results of 613.8 ± 18&#xa0;mg/g, 223.3 ± 11&#xa0;mg/g, 85.9 ± 12&#xa0;mg/g, and 87.4 ± 9&#xa0;mg/g, respectively. The adsorbed metal ions in the hydrogel can be readily desorbed using a 0.3&#xa0;M hydrochloric acid solution. The hydrogel demonstrated the ability to maintain its adsorption capacity over multiple adsorption/desorption cycles. It was concluded that the interpenetrating network hydrogels can effectively enrich heavy metal ions through electrostatic interaction between the positively charged metal ions and negatively charged carboxyl groups present in the structure. This environmentally friendly hydrogel material has the potential to serve as a high capacity, reusable, low-cost, and biomass-based sorbent for the removal of heavy metal ions from wastewater.</p> Graphical Abstract <p></p>