Removal of As(Ⅲ) and As(Ⅴ) from mine groundwater using bimetallic Fe/Cu nanoparticles.

The elimination of arsenic (As) from arsenic-contaminated mine groundwater has become a worldwide problem because it causes environmental degradation and poses serious risks to human health. In this study, biosynthesized Fe/Cu nanoparticles (Fe/Cu NPs) were used for the simultaneous elimination of As(Ⅲ) and As(Ⅴ) from aqueous solution, resulting in their maximum amounts removed at 8.5 and 17.5 mg/g, respectively. SEM, FTIR, and XPS characterizations indicate that the Fe component on the Fe/Cu NPs acted as an adsorption and catalyst, while the Cu component mainly developed into a co-precipitation reaction with the As species, also facilitating the Fe catalytic processed. Meanwhile, adsorption isotherms, kinetics, and DFT calculations reveal that the removal of As(Ⅲ) was primarily physical/chemical adsorption and oxidation, while the elimination of As(Ⅴ) was co-precipitation and chemisorption. The most stable adsorption site, receiving 0.252 and 0.306 electrons from As(Ⅲ) and As(Ⅴ), respectively, was the unsaturated complexes of iron on the Fe/Cu NPs. Finally, the measurements and XPS results of Fe/Cu NPs in the treatment of groundwater show that the reduced capacity to remove As was attributed to a complex reaction system that disrupted the function of the Cu component, including co-precipitation and made the catalytic process possible. This explains there are differences in the reaction processes of biosynthetic Cu/Fe NPs in aqueous solution and groundwater. [ABSTRACT FROM AUTHOR]