Comparing the Degradation Potential of Copper(II), Iron(II), Iron(III) Oxides, and Their Composite Nanoparticles in a Heterogeneous Photo-Fenton System

Heterogeneous photo-Fenton systems offer efficient solutions for the treatment of wastewaters in the textile industry. This study investigated the fabrication and structural characterization of novel peculiar-shaped Cu^IIO, Fe^III₂O₃, and Fe^IIO nanoparticles (NPs) compared to the properties of the iron(II)-doped copper ferrite Cu^II_0.4Fe^II_0.6Fe^III₂O₄. The photocatalytic efficiencies of these NPs and the composite of the simple oxides (Cu^IIO/Fe^IIO/Fe^III₂O₃) regarding the degradation of methylene blue (MB) and rhodamine B (RhB) as model dyes were also determined. The catalysts were synthesized via simple co-precipitation and calcination technique. X-ray diffractometry (XRD), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS) were utilized for structural characterization. The structure of Cu^IIO was bead-like connected into threads, Fe^III₂O₃ was rod-like, while Fe^IIO pallet-like, with average crystallite sizes of 18.9, 36.9, and 37.1 nm, respectively. The highest degradation efficiency was achieved by Cu^IIO for RhB and by Cu^II_0.4Fe^II_0.6Fe^III₂O₄ for MB. The Cu^IIO/Fe^IIO/Fe^III₂O₃ composite proved to be the second-best catalyst in both cases, with excellent reusability. Hence, these NPs can be successfully applied as heterogeneous photo-Fenton catalysts for the removal of hazardous pollutants. Moreover, the simple metal oxides and the iron(II)-doped copper ferrite displayed a sufficient antibacterial activity against Gram-negative Vibrio fischeri.