Nano-zno And Its Antibacterial Properties

Nano-ZnO has been an important one of photocatalysis-type inorganic antibacterial agents by its excellent Photocatalytic property. However, there are the shortcomings such as low quantum efficiency, weak Photocatalytic property, and poor antibacterial property and so on in nano-ZnO without modification. To address the above issues, the ion doping technique was applied to improve Photocatalytic property with modern preparation technologies of nanophase materials. Sb³⁺ and Mg²⁺ were doped into nano-ZnO lattice separately. Meanwhile, the antibacterial property and mechanism of nanophase powders prepared were studied on. In addition, the Photocatalytic degradation property of organic dye by doped nano-ZnO and its degraduation mechanism were also discussed in this research.In the research, a precipitation-condensation technique with non-aqueous ion exchange for removal of chlorine' was applied to prepare nanometer material. This technique has the hydrolysis of metal ions and the removal of chlorine ion occur at the same time, the anion exchange resin providing hydrolytic reagent OH and removing by-product Cl^- as well. Hydrolysis rate of Zn, Sb (or Mg) was accelerated and the preparation period was short. Non-aqueous preparation circumstance prevented polyreaction caused by moisture, and reduced agglomeration among particles. Under the condition, dehydration generated easily between metal hydroxide molecules, which leads to generation of corresponding metal oxide crystal directly. Doped nano-ZnO was analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurement. The result showed that when the ion doped concentration was lower, the lattice structure remained ZnO hexagonal lattice structure. But novel lattice structure formed as the increasing of ion doped concentration. When the mol ratio of Zn to Sb (or Mg) reached 5:1 and the ion doped concentration fell outside the doping range of ZnO solid solution, ZnO hexagonal lattice structure would be destructed thoroughly.Drying is a key step in the preparation process of nano-powders by solution chemistry method. Iso-amyl acetate was chosed as azeotropic desiccant which has polar group (carbonyl group). It can take the place of water molecule on particle surface, and formed weaker absorption with polar groups on particle surface.Two alkane chains in molecule of isopentyl acetate can stretch on the surface of particles to cover more surface areas, which is effective to prevent particles from directly contacting each other and agglomerating.The controllability of particle size was improved in the preparation process. Because of higher boiling point (142℃) of iso-amyl acetate, dehydration efficiency by azeotropic distillation was also improved.The antibacterial property of different nanophase materials was researched under luminous and non-luminous condition. The result showed that luminous condition is a sufficient condition for antibacterial property of nanometer zinc oxide. Under luminous condition, the antibacterial property of doped nano-ZnO is far higher than which of non-doped nano-ZnO. Among them, the antibacterial property of nano-ZnO doped with Sb³⁺ was higher than which of nano-ZnO doped with Mg²⁺. E.coli,S.aureus,Saccharomyces and Aspergillus niger were taken as strain tested to research the antibacterial property of different nano-powders prepared. It was found that the antibacterial property of nano-ZnO was increased remarkably by microscale dope. Especially, when mol ratio of Zn and Sb was 10:1, it was obvious to enhance antibacterial property. However, the antibacterial property of nanophase materials fell down. Antibacterial result was related to photo catalytic activity of nanophase materials, as well as cell wall structure and constitute of strain tested.Self-made photo-catalytic reactor was adopted and methyl red was taken asphotodegradation substrate in the photodegradation experiment. It was ensured that photodegradation optimum condition was ultraviolet light and ventilation.By Photocatalytic degradation experiment of methyl red, Sb³⁺ and Mg²⁺ doping increased the photo-catalytic activity of ZnO greatly, and the fitting doping mole ratio was Zn:Sb 10:1. Action mechanism of Sb³⁺ and Mg²⁺ doping on Photocatalytic activity of ZnO samples was discussed. Meanwhile, Degradation mechanism of methyl red was preliminarily studied on by degradation process tracking.