Effect of Additives on Bactericidal Effect of ZnO Solid Solutions

摘要

Effect of doping amount of either MnO_2 or CaO in ZnO solid solutions on bactericidal characteristics was studied by colony count method without the presence of tight. A single phase of ZnO with hexagonal type was obtained in the powder samples with the molar ratio below 0.11, whereas the ratio above 0.15 resulted in two phases of γ-Mn_2O_3 and solid solution. A single phase of ZnO was obtained in the samples prepared with the molar ratio below 0.11. In the molar ratio above 0.18, however, diffraction peaks corresponding to CaO with cubic type were detected in addition to solid solution. Bactericidal effect of ZnO-MnO_2 and ZnO-CaO solid solutions increased with increasing powder concentration in the medium. In the case of ZnO-MnO_2 solid solution, the bactericidal effect increased with increasing the doping amount of MnO_2 in the powder samples with the molar ratio below 0.11. In the samples with the ratio above 0.15, the effect rapidly decreased with increasing the doping amount of MnO_2. On the other hand, the bactericidal behavior of ZnO-CaO solid solution with the molar ratio below 0.11 was similar to that of ZnO-MnO_2 solid solution with the molar ratio below 0.11. At the molar ratio above 0.18, the bactericidal effect of ZnO-CaO solid solution was stronger than that of the samples with the molar ratio below 0.11.