Flower-like magnetized photocatalysts accelerating an emerging pollutant removal under indoor visible light and related phenomena

This study presents the first evidence for FeOx intra-gap states on Bi2WO6- magnetized materials enhancing the Norfloxacin (NFX) degradation with respect to Bi2WO6 within acceptable times under indoor visible light (< 5 mW/cm(2)). The kinetically faster photocatalyst Bi2WO6-FeOx contained magnetite (Fe3O4). This material lead to NFX removal within one hour and was able to degrade NFX showing a stable performance over many cycles. Evidence for the Bi2WO6-FeOx photocatalyst behaving predomonantly as a semiconductor is described in this study. Evaluation of the magnetic field effect due to the FeOx intra-gap states and the applied light intensity are correlated with acceleration of the NFX-degradation kinetics. Bi2WO6-FeOx samples show a weak photoluminescence. The pH of the solution was monitored in situ and became more alkaline by 0.3 units within the time of NFX degradation. Reactive oxygen species (ROS) have been identified to account for this observation and a preliminary mechanistic scheme is suggested consistent with the experimental runs involving redox reactions. Several surface techniques have been used to characterize the nanoparticles (NPs) surfaces of the materials used during the course of this study. Magnetic photocatalysts are shown to have a potential for practical applications compared to more traditional methods currently used in the separation of dispersed catalysts at the end of environmental cleaning processes.