Electroenzymatic catalyzed oxidation of bisphenol-A using HRP immobilized on magnetic silk fibroin nanoparticles

Electroenzymatic oxidation is an interesting approach that combines enzyme catalysis and electrode reactions. The catalytic oxidation of bisphenol-A (BPA) by an electroenzymatic method using the immobilized horseradish peroxidase (HRP) was investigated in a membraneless electrochemical reactor. To introduce HRP in the membraneless electrochemical reactor, the silk fibroin and poly (amido amine) (PAMAM) were covalently bonded onto the magnetic Fe3O4 nanoparticles to give an aminated magnetic silk fibroin nanoparticle for immobilize HRP. To evaluate the electroenzymatic degradation of bisphenol-A, electrolytic experiments were carried out with 0.5 U/mL HRP at applied potential 1.6 V, pH 5.0, 25 °C and oxygen flow rate 25 mL/min, respectively. Under the optimum condition, the removal efficiency of bisphenol-A reached 80.3%. Compared with other methods, the bisphenol-A was degraded more effectively through electroenzymatic process. The results obtained in this work provided theoretical basis for the practical application of the electroenzymatic process in the treatment of organophosphorus compounds in wastewater.