Peroxymonosulfate activation by different iron sulfides for bisphenol-A degradation: Performance and mechanism

Iron sulfide has attracted ever-increasing attention as a new group of iron-based catalysts. However, there are various iron sulfide crystals and how the crystals affect the activation performance of peroxymonosulfate (PMS) is still unclear. Herein, three iron sulfides (FeS2, Fe7S8 and Fe3S4) were prepared by hydrothermal synthesis for PMS activation toward efficient bisphenol-A (BPA) degradation. The crystal structure and surface properties of the iron sulfides were characterized and the catalytic activity for BPA degradation were compared. According to the specific surface area-normalized rate constant (k'), Fe(3)S(4)was more reactive than FeS2 and Fe7S8 for the catalytic degradation of BPA by PMS. Experiments and XPS analyses demonstrated that the lattice S in iron sulfide crystals possessed electron donating capacity, which can facilitate the regeneration of Fe(II), especially for Fe3S4. Both sulfate radical (SO4 center dot-) and singlet oxygen (O-1(2)) were generated in the catalytic systems, while (1)O(2)was identified as the primary reactive oxygen species, which was generated with superoxide radical (O-2(center dot-)) as the essential precursor. Overall, this study illustrates the way in which iron sulfide crystals affect the activation of PMS for BPA degradation.

Automated summary

This study investigates the effect of iron sulfide crystals on the activation of peroxymonosulfate (PMS) for efficient bisphenol-A (BPA) degradation. The results show that Fe3S4 exhibits higher catalytic activity compared to FeS2 and Fe7S8, and the lattice sulfur in the iron sulfide crystals possesses electron donating capacity.