Iron nanoparticles decorated TiO₂ hollow microspheres for boosting degradation of tetracycline in a photo-Fenton catalytic system

The problem of water pollution caused by antibiotic contamination is essential for human health and the ecological environment. In this study, Fe-doped TiO2 (FT-2) photocatalyst with a hollow microsphere structure was fabricated for efficient photocatalytic-Fenton removal of tetracycline (TC) under visible light irradiation. The unique hollow microsphere structure of FT-2, iron doping and oxygen vacancies enhance the photo-Fenton activity and stability of the material. The results showed that the degradation rate of tetracycline in the FT-2 photoFenton system at 60 min was 98.18%, with a degradation efficiency of mostly 90% after five successful reuses. The efficient TC degradation activity should be mainly ascribed to the structure of hollow microspheres and oxygen vacancies, resulting in the extended optical light absorption in the visible light region, reduced compound efficiency of electron cavitation pairs, and accelerated separation and migration of photogenerated carriers. In addition, this highly benefits the formation of reactive radicals center dot O-2(-) and h(+) play a key role in the TC degradation in a photo-Fenton reaction system and thus lead to great improvement in TC removal according to the capture experiments and EPR. This study provides an idea for the construction of semiconductor catalysts with oxygen vacancy and doped with transition metal elements for the effective photocatalytic remediation of wastewater containing antibiotic contaminants.