Synthesis and antimicrobial properties of CaCO₃-nAg and nAg-CaCO₃ nanocomposites

The nanocomposites of nAg-CaCO₃ and CaCO₃-nAg with different mass content of silver nanoparticles were obtained in a two-stage continuous microwave process. The nanocomposites were characterized by XRD, TEM, UV-vis, and FTIR spectroscopy. The effects of microwave radiation, silver nanoparticles content in the composite and the molar ratio of tannic acid to silver on the size of salt crystallites were studied. The effectiveness of combining silver nanoparticles with CaCO₃ was confirmed to exceed 99%. Depending on the input parameters applied, the size of salt crystals in nAg/CaCO₃ nanocomposites ranged from 25 to 45 nm, while the size of salt crystals in CaCO₃/nAg nanocomposites ranged from 26 to 41 nm. In addition, some of the compositions were tested for their antimicrobial activity on selected yeast and bacterial microorganisms. The prepared materials present a biocidal effect, which makes them suitable for use in antimicrobial preparations.