Magnetically Recoverable Halloysite–Chitin Bio‐Nanocomposite for Sustainable Zinc(II) Removal From Persian Gulf Coastal Waters

ABSTRACT A recyclable magnetic nano‐bio composite based on NiFe 2 O 4 , halloysite nanotubes (HNTs), and chitin was synthesized and applied for Zn 2+ removal from aqueous media. The composite was systematically characterized by Fourier‐transform infrared (FT‐IR), x‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET, vibrating sample magnetometry (VSM), and energy‐dispersive x‐ray spectroscopy (EDS) and exhibited rapid adsorption kinetics (equilibrium was reached within 10 min) with a maximum uptake of 357.14 mg/g at pH 6 and 25°C. Adsorption followed the pseudo‐second‐order and Langmuir models, indicating a chemisorption‐controlled monolayer process. Thermodynamic parameters confirmed that the adsorption process was spontaneous and exothermic. The material showed high reusability over 10 consecutive regeneration cycles, underscoring its stability. To demonstrate its environmental relevance, Zn 2+ monitoring data from the Persian Gulf Special Economic Zone (PGSEZ) demonstrated that shoreline concentrations frequently exceed international guideline values, highlighting urgent need for effective remediation strategies. Overall, the proposed composite thus represents not only a high‐performance sorbent for aqueous Zn 2+ removal but also a practical and sustainable option for coastal management strategies aimed at mitigating heavy metal pollution in marine ecosystems such as the Persian Gulf.