MnFe2O4磁性纳米棒非均相Fenton催化降解水中四环素的研究

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

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.

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.