PRODUCTION OF NANOPARTICLES OF AgAsS2 AND Ag3AsS3 COMPOUNDS

Abstract

Synthesis of ternary sulfides AgAsS2 and Ag3 AsS3 from systems AgNO3– As2S3, AgNO3 – NaAsO2 – Na2S and AgNO3 – As2S3 – HNO3 in ethylene glycol medium, obtained nano- and microparticles of compounds, their physicochemical properties studied. The solution stirred for 30 minutes, poured into an experimental bowl, placed in a Teflon cuvette, sealed and placed in a microwave electric heater and heated for a day at a temperature of 373-453 K. After synthesis, the precipitate filtered. For extraction, excess of arsenic washed with 0.1 M nitric acid solution, distilled water and ethanol. The purified precipitate dried at 353 K for 1 hour. It has been established that at pH = 4-6 and molar ratios of the initial components AgNO3 : As2S3  3: 2 and AgNO3: As2S3  3:1,
AgAsS2 and Ag3 AsS3 compounds, respectively, are obtained. At 373-453 K, nanoparticles formed, the size of which varies depending on the temperature and duration of heat treatment. The individuality of the synthesized compounds controlled by differential thermal and X-ray diffraction methods of analysis. According to the DTA results, the AgAsS2 and Ag3AsS3 compounds revealed two endothermic effects. The endothermic effect observed at 695 ± 2 K and 763 ± 2 K corresponds to the melting temperature of the AgAsS2 and Ag3AsS3 compounds, respectively. The endothermic effect observed at 594 K and 465 K corresponds to a polymorphic transition. According to SEM data, it found that the synthesized compound has nano- and microsizes at 413-433 K. The sizes and shapes of nanoparticles and microparticles vary depending on conditions, temperature and pH.