Mechanism of Ag-enhanced Bi2Fe4O9 photocatalytic Fenton system for inactivation of marine microorganisms

Abstract

In this work, Ag was loaded on the surface of Bi2Fe4O9 to constitute a composite photocatalyst by a photo-reduction method. Under visible light irradiation and accompanied by a small amount of H2O2 assisted to constitute a photocatalytic-Fenton coupling system, the highest sterilization rate of BFO-Ag-1 was obtained through sterilization experiments, and the sterilization rate after 30 min light irradiation reached 90.8%. This was mainly due to the fact that the silver loading not only improved the Fe(III)/Fe(II) cycle and H2O2 utilization efficiency, but also resulted in a positive shift of the valence band potential of the photocatalyst and an increase in the charge separation efficiency. Comprehensive radical trapping experiments showed that •OH and holes were the main active substances for inactivating marine microorganisms. In this work, by loading Ag nanoparticles on the surface of Bi2Fe4O9, the efficiency of the effective conversion of H2O2 to •OH was improved, which provided a new idea for the development of photocatalytic-Fenton coupling technology and ballast water treatment.