Degradation of perfluorooctanoic acid by inductively heated Fenton-like process over the Fe3O4/MIL-101 composite

To efficiently remove perfluorooctanoic acid (PFOA), we developed a composite of magnetic Fe3O4 nanocrystals and MIL-101 (an iron-based metal organic framework). Because of its high surface area, porous structure, and complexation between PFOA as confirmed by experimental results and density functional theory simulation, the magnetic composite showed a Langmuir adsorption capacity of 415 mg/g in the presence of various groundwater components, and thus adsorbed PFOA at environment-relevant concentration within 20 min. The catalyst loaded with PFOA can then be magnetically separated from the synthetic groundwater. This adsorption step concentrated PFOA near MIL-101 and resulted in a fast decomposition rate in the decomposition step, where MIL-101 served as an efficient Fenton agent due to its abundant Fe3+/Fe2+ sites. Meanwhile, the alternative magnetic field was introduced to change the production pathway of reactive oxygen species and superoxide radical anions were produced, which was critical for PFOA degradation. In addition, the inductive heating effect heat the magnetic particles to 445 K through an in-situ approach, which thus further accelerated Fenton reactions rate. In addition, and achieved a complete degradation of PFOA within 30 min. This newly developed Fenton catalyst demonstrates advantages over conventionally heterogeneous and homogeneous catalysts, and thus is promising for practical applications.