Improvement in the degradation efficiency of amorphous zero-valent iron decorated with Fe3O4 using in situ thermal oxidation

In heterogenous Fenton systems, organic pollutant degradation mainly occurs at the catalyst surface. Therefore, the surface properties and structure of catalysts are key factors that determine catalytic performance. In this paper, we used in situ thermal oxidation to generate Fe 3 O 4 on the surface of AZVI. The catalyst prepared by thermal oxidation at 375 °C for 1 h showed the best degradation performance for p-nitrophenol compared with unmodified AZVI, and the value of the reaction rate constant k was 3.1 times higher than that of the original powder. Since Fe 3 O 4 is chemically bonded to AZVI, the catalyst exhibits stable cycling properties. After 7 cycles, the modified catalyst continued to show excellent degradation capacity, and more than 97 % degradation was achieved in 15 minutes. In addition, as the number of catalyst cycles increased, more zero-valent iron was exposed, which could enhance the catalyst performance.