Sulfidation processes of PVP-coated silver nanoparticles in aqueous solution: impact on dissolution rate
|Title||Sulfidation processes of PVP-coated silver nanoparticles in aqueous solution: impact on dissolution rate|
|Publication Type||Journal Article|
|Year of Publication||2011|
|Authors||Levard, C, Reinsch, BC, Michel, FM, Oumahi, C, Lowry, GV, Brown, Jr, GE|
|Journal||Environmental Science & Technology|
Despite the increasing use of silver nanoparticles (Ag-NPs) in nanotechnology and their toxicity to invertebrates, the transformations and fate of Ag-NPs in the environment are poorly understood. This work focuses on the sulfidation processes of PVP-coated Ag-NPs, one of the most likely corrosion phenomena that may happen in the environment. The sulfur to Ag-NPs ratio was varied in order to control the extent of Ag-NPs transformation to silver sulfide (Ag(2)S). A combination of synchrotron-based X-ray Diffraction (XRD) and Extended X-ray Absorption Fine Structure spectroscopy shows the increasing formation of Ag(2)S with an increasing sulfur to Ag-NPs ratio. TEM observations show that Ag(2)S forms nanobridges between the Ag-NPs leading to chain-like structures. In addition, sulfidation strongly affects surface properties of the Ag-NPs in terms of surface charge and dissolution rate. Both may affect the reactivity, transport, and toxicity of Ag-NPs in soils. In particular, the decrease of dissolution rate as a function of sulfide exposure may strongly limit Ag-NPs toxicity since released Ag(+) ions are known to be a major factor in the toxicity of Ag-NPs.