Abstract
Background: Silver is the most often studied and the most used substance in the form of nanoparticles. Currently, the production of silver nanoparticles (SNPs) reached the level of 320 tons per year. SNPs consisting of approximately 20–15000 silver atoms. SNPs are most commonly used as antimicrobial and antifungal agents in production of clothing, cosmetics, toys, paints, and in water filters. In the field of medicine, SNPs are used in dentistry, orthopedics, surgery, and in the production of medicines.
Methods: During electric discharge between silver electrodes, plasma is produced under the effect of strong electric field with high temperature causing the removal of silver atoms from surface of the electrodes. In aqueous solutions, dissociation of water into oxygen and hydrogen atoms occurs. The interaction of active silver atoms with oxygen and hydrogen atoms and water particles causes the formation of stable nanoparticle colloid.
Results: The arc discharge produces metallic silver nanoparticles and silver ions in water, tri-Sodium citrate dehydrate (TSC), and ethanol. The size distribution of obtained SNPs has maximum size between 7 and 20 nm. The properties of colloidal silver prepared with HVAD method are analyzed by UV-Vis spectroscopy, dynamic light scattering, and transmission electron microscopy. The stability of silver colloids is tested thermal treatment under high pressure. On the basis of AAS measurements of centrifuged colloids, silver ion to SNP ratio was estimated.
Conclusions: Using HVAD method, one can produce SNPs quickly with silver concentration of approximately 15 ppm in various dispersant such as water, TSC solution, and ethanol. The aqueous solution contains 4.5% silver ions and the 3.3 μM TSC solution contains 0.5% silver ions.
Keywords: Arc discharge, ionic silver, silver colloids, silver electrodes, silver nanoparticles, tri-Sodium citrate.
Graphical Abstract