STUDIES OF SILVER ORGANOSOLS - PREPARATION, CHARACTERIZATION, AND CYANIDE-INDUCED AGGREGATION

A new simple chemical reduction method for producing silver colloids in slightly polar organic solvents is presented. The organosols in a variety of organic liquids are characterized by transmission electron microscopy, UV-visible absorption spectroscopy, and photon correlation light scattering. Typically approximately 10 nm diameter silver particles are found, stabilized by the adsorption of an organic acid additive and surfactants. Cyanide-induced aggregation is studied by the UV-visible extinction spectroscopy and surface enhanced Raman spectroscopy. The kinetics are found to be of second order and are analyzed in terms of thc colloidal structure and composition. The identities of the adsorbed cyanide species are investigated and their origin is discussed. Transitions between the various species are observed and analyzed in the light of the characteristics of the colloid. The effect of oxygen on the colloids in the presence of cyanide is investigated and compared in organosols and hydrosols.