A novel Ce-doped hydrotalcite for the efficient removal of tetracycline hydrochloride in the photo-Fenton system: from properties to mechanisms

In this study, a novel Ce-doped hydrotalcite (Ce-NiFe-LDHs) was synthesized by co-precipitation, which completely removed tetracycline hydrochloride (TC-HCl) in the photo-Fenton system within 60 min, and showed excellent stability and durability in cycling tests. In addition, the catalyst has demonstrated a wide range of adaptability to environmental conditions in the photo-Fenton system, maintaining efficient catalytic performance regardless of water quality differences, environmental factors or different types of antibiotics. The introduction of rare earth element Ce can not only effectively reduce the band gap width of the catalyst and broaden its absorption capacity in the visible light range, but also promote the efficient migration and separation of photogenerated carriers by optimizing the optical properties, further improving the catalytic efficiency. The free radical quenching experiment and electron spin resonance test revealed the core role of photogenerated hole as the main active substance. Combined with high performance liquid chromatography-mass spectrometry and density functional theory calculations, the degradation pathways were proposed. Meantime, through the Toxicity Estimation Software Tool and germination and growth test of soybean, it was found that the reaction was a process of toxicity reduction. This study provides a new strategy and theoretical basis for the future study of heterogeneous catalytic decomposition of antibiotic residues.