Research On Synthesis Mechanism And Property Of Sliver Phosphate/yeast Nanocomposites And Nano-silver

Nano-materials possess unique optical and physical properties, which have already been widely used for a leading direction of the development of materials science. Mesoporous materials play an important role as one member of nano-materials, while the development of nano-materials can also promote the development of mesoporous materials. There are many different types of mesoporous materials. Hollow spheres have caught more attention because of their core-shell structure and unique shape. They can be widely applied in drug delivery, adsorption, catalyst and so on.In this paper, we used yeast cell as a template to synthesize silver phosphate/yeast nanocomposites under normal temperature and pressure. The orthogonal test was used to optimize the synthesis conditions. Furthermore, the synthesis mechanism and properties were studied systematically. The present technology has many advantages including the mild reaction condition, the simple process, and a good structure repetition. The silver phosphate/yeast nanocomposites are characterized by X-ray diffraction, infrared spectroscopy, transmission electron microscopy and so on. Their electrochemical properties and fluorescence identification performance are studied, which show that the silver phosphate/yeast nanocomposites have efficient electrochemical properties and specific fluorescence performance. They also have important applications in optical, electrical and other fields. A detailed analysis and argumentation are given on the synthesis method by using of yeast as a template according to the hard and soft acid base theory, ion exchange and redox mechanisms, biomineralization and crystal nucleation and growth theory, which suggest that yeast cells act as catalyst and template in the synthesis of silver phosphate/yeast nanocomposites.In our work, uniform sized nano-silver hollow spheres were prepared using yeast cells as the template and characterized by XRD, TEM, SEM and UV-visible absorption spectra. We also studied the photocatalytic degradation properties of mesoporous titanium dioxide modified by nano-silver hollow spheres in degrading methyl orange. The results show that nano-silver hollow spheres have a synergy to photocatalytic degradation properties of titanium dioxide.We have also prepared hydroxyapatite carrying silver mesoporous material. Its structure and antibacterial property are characterized. Experiments show hydroxyapatite had no antibacterial property , while hydroxyapatite carrying silver can effectively kill Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Ntibacterial activity of silver phosphate and nano-silver were further characterized, which revealed that silver materials prossess good antibacterial effects.