Ball milling of pyrite in air to significantly promote the Fenton reaction: A mechanistic study.

Natural pyrite (FeS) has been widely used as heterogenous Fenton catalyst due to the unique iron supplying and ferrous regeneration performance, however, natural pyrite has poor catalytic activity due to the low surface reactivity. Ball milling is commonly used to modify pyrite, but the mechanism has not been thoroughly studied. In our work, by optimizing the ball milling conditions, the catalytic efficiency of modified pyrite is increased by 60 times compared to natural pyrite, and the ball milled pyrite Fenton system was able to degrade dyes and a series of antibiotics within 30 min. Compared to ball milling in nitrogen and vacuum, ball milling in air increased the proportion of S and active iron sites on the surface of pyrite, which assisted and accelerated the regeneration of ferrous and enhanced the iron supplying performance. This work explored the mechanisms of ball milling to modify the properties of pyrite, reported a green and efficient ball milled pyrite Fenton system, and provided a new insight in regulating ball milling conditions for mechanochemical modification.