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

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 Fe 3 O 4 with Fe 2 O 3 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 H 2 O 2 degradation, values of 27.9, 14.8, 20.4 and 0. 2 μg H 2 O 2 per unit POX were achieved for Cr( ii )/Fe 3 O 4 /Fe 2 O 3 /POX, Cr( iii )/Fe 3 O 4 /Fe 2 O 3 /POX, Mn( ii )/Fe 3 O 4 /Fe 2 O 3 /POX and pure peroxidase (POX), respectively, confirming the catalytic efficiency of the carrier-embedded enzyme, demonstrating that the developed method enhances the peroxidase efficiency. This paper presents a process for synthesising iron oxide nanoparticles modified with Cr( ii ), Cr( iii ) and Mn( ii ) ions and immobilised peroxidase.