Ion Release Kinetics and Particle Persistence in Aqueous Nano-Silver Colloids

Many important aspects of nanosilver behavior are influenced by the ionic activity associated with the particle suspension, including antibacterial potency, eukaryotic toxicity, environmental release, and particle persistence.The present study synthesizes pure, ion-free, citrate-stabilized nanosilver (nAg) colloids as model systems, and measures their time-dependent release of dissolved silver using centrifugal ultrafiltration and atomic absorption spectroscopy. Ion release is shown to be a cooperative oxidation process requiring both dissolved dioxygen and protons. It produces peroxide intermediates, and proceeds to complete reactive dissolution under some conditions. Ion release rates increase with…

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  Brown University