Estrone removal by horseradish peroxidase immobilized on a nanofibrous support with Fe3O4 nanoparticles

Abstract

The occurrence, fate, and removal of estrone (E₁) from environmental systems have attracted considerable research interests in recent years because of the potential risks of human and wildlife exposure to E₁. This study aims to develop an efficient enzymatic method to remove E₁ from water. Electrospinning composite fibers (200–300 nm in diameter), comprising poly(vinyl alcohol) (PVA), poly(acrylic acid) (PAA), SiO₂, and Fe₃O₄ nanoparticles (NPs), were used as supports for horseradish peroxidase (HRP) immobilization. The immobilized HRP was used for E₁ removal. The effects of Fe₃O₄ NPs on the degradation and adsorption of E₁ by the prepared materials were investigated. The results showed that the immobilized HRP was less sensitive to the changes in pH and temperature compared with free HRP. The immobilized HRP also exhibited relatively high stability and reusability. HRP-PAA/PVA/SiO₂ nanofibrous membranes with Fe₃O₄ NPs (HRP-Fe₃O₄ NPs/NFM) showed a significantly higher relative activity for E₁ removal (84.5%) than the nanofibrous membranes without Fe₃O₄ NPs (79.4% P < 0.05). This improvement can be attributed to the addition of Fe₃O₄ NPs which increased the adsorption ability of the membranes and improved the catalytic activity of the immobilized HRP. The HRP-Fe₃O₄ NPs/NFM is suitable for use in wastewater treatment owing to its high reusability.