Targeted Ni( <scp>II</scp> ) Removal by Synergistic <scp>PVA</scp> / <scp>AMPy</scp> Co‐Modification of Starch‐Based Hydrogel Microspheres From Simulated Multi‐Ion Wastewater

ABSTRACT The selective removal of nickel ions (Ni 2+ ) from multicomponent wastewater represents a significant environmental challenge. In this study, a novel composite hydrogel microsphere adsorbent, PVA/AMPy‐SH, was developed by synergistically integrating a polyvinyl alcohol (PVA)‐reinforced starch network for structural stability and 2‐(aminomethyl)pyridine (AMPy) as a specific chelating ligand for Ni 2+ . This synergistic design, which integrates the PVA network with AMPy functionalization, relative to conventional adsorbents, provides improved mechanical strength, enhanced adsorption capacity, and superior ion selectivity. The adsorption process followed the Langmuir isotherm model, with a fitted maximum adsorption capacity of 272.64 mg g −1 , and the adsorption kinetics were consistent with the pseudo‐second‐order kinetic model. Notably, the adsorbent demonstrated exceptional selectivity toward Ni 2+ , with separation factors ( β ) reaching 56 against competing ions, and retained 86.13% of its initial adsorption capacity over six consecutive adsorption–desorption cycles. This work presents a rational design strategy for developing reusable adsorbents for targeted metal recovery from complex wastewater systems.