Bioengineered Iron Nanoparticles From Canavalia cathartica Seeds: A Promising Nanobiosorbent for Cr (VI) Remediation

ABSTRACT

This study reports the green synthesis of iron nanoparticles (FeNP‐CC) using aqueous seed extract of Canavalia cathartica , a less explored mangrove associate, and evaluates their efficacy in the remediation of hexavalent chromium (Cr(VI)) from aqueous systems. Phytochemical and spectroscopic analyses using LC‐MS/MS, UV–visible spectroscopy, FTIR, HR‐TEM, and XRD confirmed that bioactive constituents such as polyphenols and L‐canavanine acted as both reducing and stabilizing agents during the synthesis of FeNP‐CC, resulting in nanoparticles with a nanocrystalline core–shell morphology. Adsorption experiments revealed that Cr(VI) removal followed pseudo‐second‐order kinetics, suggesting a chemisorption‐dominated mechanism. Equilibrium studies fitted best to the Freundlich isotherm model ( R ² = 0.99), indicating multilayer adsorption on a heterogeneous surface. Optimal removal (100%) was achieved for 10 mg/L Cr(VI) within 50 min under acidic conditions. Furthermore, FeNP‐CC successfully remediated complex, real‐world laboratory wastewater containing 30 mg/L Cr(VI) despite competitive matrix interferences. Overall, this biogenic nanobiosorbent represents a highly sustainable, low‐cost, and efficient candidate for practical wastewater purification.