Visible-light-driven peroxymonosulfate activation by FeS₂ nanoplates for simultaneous oxidation of arsenite and organic dyes

Due to rapid industrial development, numerous dye pollutants and heavy metals, such as arsenic (As), have contaminated water sources, causing complex pollution that threatens both the ecological environment and human health. Therefore, there is an urgent need to design an effective strategy for treating complex dye wastewater. Herein, we have constructed high-purity pyrite FeS₂ nanoplates as bifunctional catalysts for the simultaneous removal of dyes and arsenite (As(III)). We have developed a visible light-assisted peroxymonosulfate (PMS) activation method to remove typical organic dye pollutants (e.g., rhodamine B, malachite green, methyl orange, methylene blue) and toxic As(III). The FeS₂/Light/PMS system can remove 100 % of all dye pollutants and more than 85 % of As(III) within 18 min simultaneously with high cyclic stability, which is believed to be effective in complex pollution control. It is confirmed that the multivalent Fe ions and S₂²⁻ are the main active centers, and the free radical and non-free radical pathways synergistically enhance the oxidation of dye pollutants, in which SO₄^·- and ¹O₂ are the main reactive oxygen species. This work presents a facile strategy for developing a metal sulfide-based Fenton-like system for treating complex dye wastewater.