Change of antibacterial activity with oxidation of ZnS powder

Abstract

The antibacterial activities of samples prepared from oxidation of ZnS powder were studied by measuring the change in electrical conductivity with the growth of Escherichia coli. Oxidation of ZnS occurred at above 550°C in air and then the amount of ZnO increased with increasing the oxidizing temperature. The obtained crystal structure of ZnO was a zinc-blende type. From results of antibacterial tests on ZnS powder samples before and after oxidation, the antibacterial activity was found to increase with increasing the oxidizing temperature. However, no activity of ZnS was observed, irrespective of the powder concentration. The pH value after dispersing the powder samples in physical saline solution was in the range between 5.5 and 8.0, increasing with the formation of ZnO.