Photoelectrochemical and optical fenton properties of Cu-doped ZnFe2O4 composites synthesized by hydrothermal method

The non-homogeneous photo- Fenton technology has been widely used in the field of water treatment due to its environmental friendliness and non-production of iron sludge. However, the recombination of electron–hole pairs limits the catalytic activity of photo- Fenton materials. In this study, a simple hydrothermal method was designed to prepare Cu-doped ZnFe₂O₄ for the efficient removal of tetracycline The material composition and optical properties of the catalyst were characterized using x-ray diffractio scanning electron microscopy transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy. The results showed that the doping of transition metals was introduced to significantly increase the catalytic activity of the catalyst. At a pollutant concentration of 50 mg L⁻¹, ZnFe₂O₄ doped with 1% Cu degraded 97.9% of tetracycline in 60 min with a degradation rate of 0.0498 min⁻¹, which was 12.8 times higher than that of pure ZnFe₂O₄. O₂⁻ and ·OH were found to be the main reactive oxygen species (ROS) causing the degradation. The photo-Fenton efficiency of Cu/ZnFe₂O₄ is still very efficient after five tetracycline degradations (87.2%), and the crystal structure is stable, indicating good stability and the possibility of recycling in photo-Fenton applications.