Fabrication of chitosan supported Fe/Co/Ni trimetallic nanocomposite multifunctional catalyst for reduction of Rhodamine-B, Methylene Blue and Potassium ferricyanide

This study reports the facile in-situ fabrication of a chitosan-supported Fe/Co/Ni trimetallic nanocomposite designed as a high-performance catalyst for environmental remediation. Structural and surface analysis, including XRD, XPS, FESEM and EDS, confirmed the formation of a highly crystalline trimetallic spinel oxide phase uniformly anchored within the biocompatible chitosan scaffold. Spectroscopic investigations (FTIR and XPS) elucidated a synergistic mixed-valence electronic environment involving Fe 2+ /Fe 3+ , Co 2+ and Ni 2+ cations. These metallic centers are stabilized through coordination with the nitrogen and oxygen lone pairs of the chitosan backbone, and ensuring long-term structural integrity. The catalytic efficiency was evaluated through a comparative kinetic study focusing on the reductive degradation of Methylene Blue (MB), Rhodamine B (RhB), and the inorganic probe potassium ferricyanide (K 3 [Fe(CN) 6 ]). All reduction processes obeyed pseudo-first-order kinetics, revealing the catalyst’s superior electron-transfer capabilities. The nanocomposite demonstrated multifunctional utility by facilitating the oxidative photo-Fenton mineralization of organic dyes under visible light via hydroxyl radical (⋅OH) generation. The catalyst exhibited excellent reusability and magnetic recoverability, retaining > 91% of its initial activity over five consecutive cycles. These findings highlight the Fe/Co/Ni-chitosan nanocomposite as a versatile and sustainable material for the comprehensive treatment of industrial wastewater.