Recyclable core-shell hydrogel doped with nano-β-FeOOH for efficient adsorption of copper ions

The remediation of wastewater contaminated with heavy metals remains a serious challenge due to the continuing threats posed to ecosystems and human health. While conventional methods such as membrane filtration and flocculation exist, developing sustainable adsorbents with high capacity and reusability is imperative. Therefore, we propose a novel strategy to overcome the limitations of natural polymer-based hydrogels by integrating β-FeOOH nanoparticles into sodium alginate matrices. FTIR, XPS and TG reveal that the incorporation of β-FeOOH not only increases the adsorption active sites but also improves the thermal stability of the composite hydrogels. The composite hydrogel exhibits exceptional adsorption capacity (581.40 mg/g). Crucially, the material maintains over 85 % of its initial efficiency after five adsorption-desorption cycles, demonstrating strong structural integrity and practical applicability. This work provides a mechanistic framework for designing multifunctional hydrogels through nanomaterial hybridization, offering a sustainable pathway for water purification technologies.