Change in Antibacterial Activity with Doping Amount of MnO₂ in ZnO-MnO₂ Solid Solution

Abstract

Antibacterial activity of ZnO-MnO₂ solid solution was studied by a colony count method.ZnO-MnO₂ solid solution powders were prepared by heating at 1400 for 3h in air.After milling the solid solution powders, the average particle size became 0.5 μm, which were used in antibacterial tests.A single phase with hexagonal type structure was obtained in the samples doped below 10 mol% MnO₂ in solid solution.From the results of antibacterial tests, the activity increased with increasing the powder concentration in the medium.At the doping amount of 5 mol% MnO₂ in solid solution, it was found to show a strong antibacterial activity.In the doping amount above 5 mol%, the activity decreased with increasing the amount of MnO₂.The occurrence of antibacterial activity was supposed to be due to the generation of active oxygen from solid solution.