Green-synthesized magnetic iron oxide nanoparticles for the adsorptive removal of CD2+ and PB2+ from aqueous solution

The toxic persistence of cadmium and lead in water supplies demands sustainable and high‐performance remediation strategies. This study reports the green synthesis of magnetic Fe 2 O 3 nanoparticles (IONPs) using leaf extracts of Icacina oliviformis (false yam) as a benign reducing and capping agent. Batch adsorption experiments were carried out with initial metal ion concentrations of 0.5–3.5 mg L −1 , varying pH, temperature (30–90 °C), adsorbent dose (0.03–0.15 g per 100 mL), and contact time (5–60 min). Under optimized conditions, (2.5 mg L −1 metal ion concentration, pH 10, 0.05 g IONP, 25 °C, 150 rpm), the nanoparticles achieved 94% Cd (II) and 93% Pb (II) removal within 30 min. The experimental equilibrium capacities reached up to 3.48 mg g −1 for Cd ions and 2.75 mg g −1 for Pb (II). Isotherm analysis showed that adsorption conforms best to the Freundlich model (R 2 ≈ 0.70), indicating heterogeneous, multilayer uptake, while kinetic data fitted best the pseudo-second-order model (R 2 > 0.79), consistent with chemisorption via surface complexation. The regeneration study resulted in adsorption efficiency decreasing from 96.80 to 52.10% during the course of four regeneration cycles for Pb and 92 to 41.3% for Cd. The rapid kinetics, high efficiency, and magnetic recoverability underscore the potential of these IONPs as cost-effective, recyclable adsorbents for heavy-metal remediation. Future studies will target column performance and real‐effluent trials to advance toward pilot‐scale implementation.