MnFe2O4磁性纳米棒非均相Fenton催化降解水中四环素的研究

采用水热合成法成功制备出MnFe₂O₄磁性纳米棒（s-MnFe₂O₄），并考察了商品化的Fe₃O₄、MnFe₂O₄和合成的s-MnFe₂O₄纳米棒这3种磁性纳米颗粒作为非均相Fenton催化剂降解水中四环素抗生素的性能.同时，采用X射线衍射（XRD）、透射电镜（TEM）、N₂吸附-脱附、振动样品磁强计（VSM）及X射线光电子能谱（XPS）等技术对催化剂的理化性质进行了表征.非均相Fenton催化降解四环素的结果表明，s-MnFe₂O₄具有最高的催化活性，反应180 min，四环素的去除率可以达到87.6%，TOC的去除率达到47.5%.自由基捕获试验证实了羟基自由基（·OH）是非均相Fenton氧化过程中的主要活性物种.s-MnFe₂O₄磁性纳米棒的高催化活性归因于其表面拥有较高含量的Mn³⁺和Fe²⁺物种，它们的存在能加速界面电子的转移效率，从而促进·OH的生成.合成的s-MnFe₂O₄催化剂具有良好的稳定性，循环使用6次，四环素的去除率仅从87.6%降低到80.2%，且氧化过程中活性组分的流失很少.

Heterogeneous Fenton degradation of tetracycline in water catalyzed by magnetic MnFe2O4 nanorods

Magnetic MnFe₂O₄ nanorods (s-MnFe₂O₄) were successfully prepared by the hydrothermal synthesis. The commercial Fe₃O₄, MnFe₂O₄ and the synthesized s-MnFe₂O₄ were tested as heterogeneous Fenton catalysts in the degradation of tetracycline antibiotic in water. The physical and chemical properties of these catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂ adsorption-desorption, vibrating sample magnetometer (VSM) and X-ray photoelectron spectroscopy (XPS). The results showed that s-MnFe₂O₄ exhibited the highest catalytic activity in the degradation of tetracycline. After the reaction of 180 min, the removal rate of tetracycline and TOC were 87.6% and 47.5%, respectively. Based on the quenching experiments, hydroxyl radicals (·OH) were confirmed to be the main active species during the heterogeneous Fenton reaction. The enhanced catalytic activity of s-MnFe₂O₄ was ascribed to the higher content of Mn³⁺ and Fe²⁺, which enhanced the interfacial electron transfer and promoted the generation of ·OH radicals. The stability of s-MnFe₂O₄ catalyst was confirmed to be fairly good and a slight leaching of active component was observed.