Synthesis of Fe3O4/Fe2O3 nanoparticles modified with peroxidase with incorporated chromium and manganese ions

Abstract

This paper presents a process for synthesising iron oxide nanoparticles modified with Cr(II), Cr(III) and Mn(II) ions and immobilised peroxidase. The obtained bionanocatalyst can be successfully applied to biocatalytic hydrogen peroxide decomposition reactions in pollutant removal processes. The iron oxide nanoparticles formed by Fe₃O₄ with Fe₂O₃ displayed sizes below 10 nm. The sorption capacities of the material for Cr(II), Cr(III) and Mn(II) ions were 8.81, 5.30, and 5.01 mg g⁻¹, respectively. In the second step, after adsorption of the ions, the materials were subjected to peroxidase immobilisation processes, yielding biocatalysts with hydrogen peroxide degradation activities of, respectively 1.5, 2.1 and 1.4 units per mg. For H₂O₂ degradation, values of 27.9, 14.8, 20.4 and 0. 2 μg H₂O₂ per unit POX were achieved for Cr(II)/Fe₃O₄/Fe₂O₃/POX, Cr(III)/Fe₃O₄/Fe₂O₃/POX, Mn(II)/Fe₃O₄/Fe₂O₃/POX and pure peroxidase (POX), respectively, confirming the catalytic efficiency of the carrier-embedded enzyme, demonstrating that the developed method enhances the peroxidase efficiency.