Peroxidase-Like Activity of Ferrihydrite and Hematite Nanoparticles for the Degradation of Methylene Blue

الملخص EN

The peroxidase-like catalytic properties of 2-line ferrihydrite (2LFh) and hematite nanoparticles (NPs) for the degradation of methylene blue (MB) were studied.

It is highlighted that the hematite NPs were prepared from the transformation of the metastable 2LFh NPs.

It was found that the 2LFh NPs exhibited poor crystallinity with an average size of 5 nm, while the hematite NPs exhibited high crystallinity with an average size of ca.

100 nm.

It was found that the total degradation of MB occurred for hematite NPs, while only a maximum degradation of 69% was possible for the 2LFh NPs.

The Michaelis–Menten parameters indicated that the hematite NPs present higher catalytic activity than the 2LFh NPs at basic pH.

It was found that the ordered surface of the hematite NPs has a stronger effect for the degradation of MB than its low surface area.

It was concluded that the crystal planes of the hematite NPs affect the catalytic process more significantly than the high surface area of 2LFh NPs.