Investigations of UV photolysis of PVP-capped silver nanoparticles in the presence and absence of dissolved organic carbon

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology 2013-05, Vol.15 (5), p.1, Article 1673
• Main Authors: Poda, Aimee R., Kennedy, Alan J., Cuddy, Michael F., Bednar, Anthony J.
• Format: Article
• Language: English
• Subjects: Carbon; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Dissolved organic carbon; Exact sciences and technology; Fractionation; Inorganic Chemistry; Irradiation; Lasers; Mass spectrometry; Materials Science; Nanocrystalline materials; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Nanotechnology; Optical Devices; Optics; Photolysis; Photonics; Physical Chemistry; Physics; Radiation effects on specific materials; Research Paper; Silver; Structure of solids and liquids; crystallography; Toxicity; Ultraviolet radiation; Zooplankton
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-013-1673-7

This study investigated the effect of UV irradiation on the characteristics and toxicity of 50 nm (nominal diameter) polyvinylpyrrolidone-capped silver nanoparticles (AgNPs) in the presence and absence of dissolved organic carbon (DOC). The photolysis resulted in a decrease in average particle size as measured by field flow fractionation interfaced with inductively coupled plasma mass spectrometry. The decrease in size was attributed to the photo-induced oxidation of the PVP and dissolution of metallic silver. Moreover, photolysis of the AgNPs in solutions containing DOC appeared to give rise to small nanoparticles (~5 nm) formed via reduction of dissolved silver ions. These results were consistent with photolysis of AgNO 3 solutions initially devoid of nanoparticles. Thus, the carbon-containing constituents of DOC serve as reducing agents for Ag + , primarily under conditions of UV irradiation. The standard zooplankton model, Daphnia magna , indicated that the toxicity of nanosilver was significantly reduced when the AgNPs have been exposed to UV light. Observed toxicity was further reduced when AgNPs in DOC-containing solutions were exposed to UV. These results suggest that environmentally relevant conditions such as DOC and UV light are important mitigating factors that mediate the aquatic toxicity of AgNPs.