Size-Controlled Dissolution of Organic-Coated Silver Nanoparticles
- Duke
The solubility of Ag NPs can affect their toxicity and persistence in the environment. We measured the solubility of organic-coated silver nanoparticles (Ag NPs) having particle diameters ranging from 5 to 80 nm that were synthesized using various methods, and with different organic polymer coatings including poly(vinylpyrrolidone) and gum arabic. The size and morphology of Ag NPs were characterized by transmission electron microscopy (TEM). X-ray absorption fine structure (XAFS) spectroscopy and synchrotron-based total X-ray scattering and pair distribution function (PDF) analysis were used to determine the local structure around Ag and evaluate changes in crystal lattice parameters and structure as a function of NP size. Ag NP solubility dispersed in 1 mM NaHCO{sub 3} at pH 8 was found to be well correlated with particle size based on the distribution of measured TEM sizes as predicted by the modified Kelvin equation. Solubility of Ag NPs was not affected by the synthesis method and coating as much as by their size. Based on the modified Kelvin equation, the surface tension of Ag NPs was found to be {approx}1 J/m{sup 2}, which is expected for bulk fcc (face centered cubic) silver. Analysis of XAFS, X-ray scattering, and PDFs confirm that the lattice parameter, {alpha}, of the fcc crystal structure of Ag NPs did not change with particle size for Ag NPs as small as 6 nm, indicating the absence of lattice strain. These results are consistent with the finding that Ag NP solubility can be estimated based on TEM-derived particle size using the modified Kelvin equation for particles in the size range of 5-40 nm in diameter.
- Research Organization:
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
- Sponsoring Organization:
- NSFEPA
- OSTI ID:
- 1036890
- Journal Information:
- Environ. Sci. Technol., Journal Name: Environ. Sci. Technol. Journal Issue: (2) ; 01, 2012 Vol. 46; ISSN ESTHAG; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- ENGLISH
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Related Subjects
ABSORPTION
COATINGS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DISSOLUTION
DISTRIBUTION FUNCTIONS
FINE STRUCTURE
GUM ACACIA
LATTICE PARAMETERS
MORPHOLOGY
ORGANIC POLYMERS
PARTICLE SIZE
SCATTERING
SILVER
SOLUBILITY
SPECTROSCOPY
SURFACE TENSION
SYNTHESIS
TOXICITY
TRANSMISSION ELECTRON MICROSCOPY