Highly Efficient Photo-Fenton Ag/Fe2O3/BiOI Z-Scheme Heterojunction for the Promoted Degradation of Tetracycline

Abstract

Novel Ag/Fe2O3/BiOI Z-scheme heterostructures are first fabricated through a facile hydrothermal method. The composition and properties of as-synthesized Ag/Fe2O3/BiOI nanocomposites are characterized by powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, UV-Vis diffuse reflectance spectra, etc. The Ag/Fe2O3/BiOI systems exhibit remarkable degradation performance for tetracycline (TC). In particular, the composite (Ag/Fe2O3/BiOI-2) shows the highest efficiency when the contents of Ag and α-Fe2O3 are 2 wt% and 15%, respectively. The effects of operating parameters, including the solution pH, H2O2 concentration, TC concentration, and catalyst concentration, on the degradation efficiency are investigated. The photo-Fenton mechanism is studied, and the results indicated that •O2− is the main active specie for TC degradation. The enhanced performance of Ag/Fe2O3/BiOI heterostructures may be ascribed to the synergic effect between photocatalysis and the Fenton reaction. The formation of Ag/Fe2O3/BiOI heterojunction is beneficial to the transfer and separation of charge carriers. The photo-generated electrons accelerate the Fe2+/Fe3+ cycle and create the reductive reaction of H2O2. This research reveals that the Ag/Fe2O3/BiOI composite possesses great potential in wastewater treatment.