Magnetically separable TiO2/FeOx/POM accelerating the photocatalytic removal of the emerging endocrine disruptor: 2,4-dichlorophenol

This study presents the magnetically separable TiO2/FeOx microstructure decorated with poly-oxo-tungstate (POM) leading to the endocrine disruptor 2,4-dichlorophenol (2,4-DCP) under low intensity solar light. The fastest 2,4-DCP degradation kinetics was obtained by way of the TiO2/FeOx(25%)/POM(1%) composite in acidic media. The use of magnetized photocatalysts avoids the high cost separation of the catalysts from the solution by conventional treatments after 2,4-DCP-degradation. Reactive oxygen species (ROS) leading to the 2,4-DCP degradation were identified by use of appropriate scavengers. The 2,4-DCP degradation increased with the applied light intensity (fluence rate) providing evidence for the semiconductor behavior of the composite material. FeOx/Fe2O3 infra-gap states were identified by X-ray photoelectron spectroscopy (XPS) leading to 2,4-DCP degradation. A scheme for the interfacial charge transfer (IFCT) between the oxides is suggested based on the electronic energy position of the oxides making up the photocatalytic composite.