METHOD OF PRODUCING SILVER NANOPARTICLES WITH SIZE OF 30 ± 3 NM Russian patent published in 2020 - IPC B01J13/00 B82B3/00 B22F9/24 

FIELD: chemistry.

SUBSTANCE: invention relates to colloidal chemistry, particularly to production of conditioned colloidal silver nanoparticles by a nitrate method, which can be used in medicine, agriculture, biology, etc. Silver nanoparticles of size 30 ± 3 nm are obtained by reduction and stabilization of silver nitrate (AgNO₃) with sodium citrate (Na₃C₆H₅O₇) at ratio of concentrations of AgNO₃/Na₃C₆H₅O₇ solutions - 1:0.75 and their volumes of 5:1. In the Erlenmeyer flask one prepares 80 ml of 0.002 M AgNO₃ solution and adds a "stirring" rod of the magnetic mixer. Refluxer is put on flask and installed on magnetic stirrer with heating, where temperature is set to 300 °C and mixing mode is 375 rpm. When the first signs of boiling, which confirm the beginning of condensate flowing along the walls of the dephlegmator and/or bulb, 16 ml of 0.0075 M solution of Na₃C₆H₅O₇ are added. When colour of solution changes to yellowish one changes mixing mode by 500 rpm, temperature by 200 °C. From the moment of change of colour of the solution to its yellow one boils for 20 minutes, after which the return cooler is disconnected, the flask is removed from the magnetic mixer and allowed to cool at room temperature for 18–24 hours.

EFFECT: invention enables to obtain colloidal silver series standard series size 30 ± 3 nm without signs of aggregation and crystallisation.

1 cl, 2 dwg, 4 tbl