Synergistic effect between pyrite and Fe-based metallic glass for the removal of azo dyes in wastewater

Fe-based metallic glasses (FeMGs) are popular reductants for the restoration of wastewater containing various pollutants, but it still suffers from surface passivation and a narrow applicable pH range. In this work, pyrite, an abundant iron sulfide, was used to enhance the reactivity of FeMGs for the removal of azo dye. Synergetic effects between pyrite and FeMGs improved the removal of Orange II when using an FeMGs/pyrite mixture, where the reaction rate constant kobs was 0.218 min-1, which was higher than when using FeMGs alone (0.114 min-1). Orange II was removed at pH0 ranging from 5.0 to 10.0 in the presence of pyrite, while it was inefficiently removed by FeMGs alone (10 g/L) at pH0 10.0. Mechanistic investigations showed that the synergistic effect between FeMGs and pyrite enhanced the surface corrosion of FeMGs and accelerated the Fe3+/Fe2+ redox cycle to generate more sorbed Fe2+, which was the dominant reactive species during Orange II removal. This study proposes an approach for enhancing the removal of dye wastewater by using FeMGs to treat mine waste.

Automated summary

This study finds that the reactivity of Fe-based metallic glasses (FeMGs) for the removal of azo dye can be enhanced by using abundant pyrite, an iron sulfide. The synergetic effects between pyrite and FeMGs improve the removal efficiency of Orange II, and it can be applied in a wide range of pH values. This study proposes a new approach for treating dye wastewater in mine waste using FeMGs.