科研之友
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摘要
Mn-oxide microstructures were investigated by XRD, FT-IR, TEM, FE SEM and EDS techniques. The oxidation of the aqueous solutions of manganese (II) chloride by hydrogen peroxide was employed to synthesize pure 20-30-nm pseudospherical hausmannite (Mn3O4) nanoparticles and manganite (gamma-MnOOH) nanowires. The alpha-MnO2 nanotubes and nanorods were hydrothermally synthesized starting from a KMnO4 precursor, then modified with the addition of divalent metal cations Mn2+, Cu2+, NO2+ and Fe2+. The modification with Mn2+ induced the transformation of alpha-MnO2 nanotube into 3D beta-MnO2 (pyrolusite) prismatic nanoparticles, whereas the low-crystalline a-MnO2 nanorods were transformed into disk-like gamma-MnO2 nanoparticles. The modification with Cu2+. and Ni2+ induced the structural transformation of alpha-MnO2 into a mixture of MnO2 polymorphs. The modification with Cu2+ decreased, whereas the modification with Ni2+ improved the crystallinity of MnO2. The modification with Fe2+ induced the structural transformation of alpha-MnO2 into gamma-MnO2, a decrease in crystallinity and the segregation of alpha-Fe2O3 (hematite). Thus the modification of MnO2 with Fe2+ (Mn2+) divalent metal cations that can be oxidized into Fe2+ (Mn4+) by a KMnO4 precursor differs significantly in comparison with, in this case, nonoxidizable cations such as Cu2+ and NO2+. On the other hand, the advantage that the modification of MnO2 with Mn2+ produces chemically identical compounds with different morphology can be used as a model system for toxicity studies. In this work the preliminary measurements of intracellular oxidative stress in epithelial cells induced by manganese oxide nanoparticles are reported.
- 出版日期2013-7-24
