NANOSILVER COLLOIDAL SOLUTION AND PREPARATION METHOD THEREOF Russian patent published in 2012 - IPC C22B11/00 C25C1/20 B82B3/00 

FIELD: chemistry.

SUBSTANCE: method involves electrochemical stripping of silver in deionised water. Electrochemical stripping is carried out using silver in form of a fine powder with chemical purity 99.999% and particle size of up to 100 nm. The process is carried out in an electrolysis cell, inside of which there are electrodes in form of containers made from chemically neutral material which hold 100-150 g of the fine silver powder and, through a conductor which is in a chemically neutral cladding, supply constant voltage of 30-45 V. Electrolysis is carried out in conditions of cyclic variation of voltage polarity every 2 hours, and the solution is stirred twice a day until achieving silver concentration in the colloidal solution of 5.0-100.0 mg/l. The fraction of nanoparticles of silver metal ranges from 5 to 90% of the total concentration of silver in the solution, the fraction of nanoparticles with size from 2 to 15 nm ranges from 65 to 85% of the total volume of nanoparticles in the solution, the fraction of nanoparticles with size from 15 to 35 nm ranges from 15 to 35% respectively, the remaining fraction of total concentration of silver in the solution is composed of silver ions.

EFFECT: obtaining a stable colloidal solution of nanosilver.

6 cl, 1 ex