Synthesis of silver nanopowders at high concentrations via green nanotechnology

Abstract

A novel technique for a mass scale production of spherical silver particles powders was developed. A green chemical technique was employed for the preparation of high concentration silver particles colloid (50000 – 100000 ppm). The silver particles powder could be easily precipitated from the colloid. The results from scanning electron microscope (SEM) and dynamic light scattering particle size analyzer indicated a controllable size from nano-scale to micro-scale ranges associated with the employed conditions including concentration of silver salt, concentration of reducing saccharine, pH, and the mixing sequence. Since the synthetic system was designed to meet green chemistry protocols (i.e., using natural substances as the environmentally reducing agent, controlling the complete reduction of silver salt, reducing derivatives, generating no by-products, and performing all procedure under the atmospheric conditions), the production cost is very low and very economic competitive compared that using the conventional borohydride chemistry. The silver particles powders can be employed as raw materials in various industries, such as filler for nanocomposites, conductive silver ink in electronic industry, surface coating for antibacterial applications, and nanosilver clay in jewelry industry.