Green Nanoengineered Keratin Derived Bio‐Adsorbent for Heavy Metals Removal from Aqueous Media

Abstract Exploiting poultry chicken feathers, a keratin‐rich by‐product offers a sustainable raw material for bio‐adsorbents in water remediation. This study developed a bio‐adsorbent from chicken feathers keratin (CFK), functionalized with surface‐modified graphene oxide (SMGO). The bio‐adsorbent was tested for adsorbing metal cations (Pb, Cd, Ni, Zn, Co) and oxyanions (As, Se, Cr) from water contaminated with 600 µg/L of each metal at pH 5.5, 7.5, and 10.5. Results showed optimal removal efficiencies at pH 7.5, with anions achieving ≥91.10% for As (III), ≥89.55% for Cr (VI), and ≥74.33% for Se (IV). Cations removal reached 96.34% for Co (II), 97.36% for Ni (II), 99.03% for Cd (II), 99.21% for Pb (II), and 59.06% for Zn (II). Kinetic studies indicated rapid initial uptake within the first 6 hours, reaching equilibrium at 24 hours. The bio‐adsorbent maintained high adsorption capacities over four regeneration cycles with minimal efficiency loss, showing strong stability and reusability. Removal efficiency followed the order: Pb (II) 〉 Cd (II) 〉 Ni (II) 〉 Co (II) 〉 Zn (II), correlating with their ionic radii. Ni ²⁺ adsorbed more effectively than Co ²⁺ due to a smaller ionic radius and stronger electrostatic attraction. These findings highlight CFK‐SMGO's efficacy in wastewater treatment, promoting bio‐based sustainable adsorbents.