| Because each component of matrix magnetic nanocomposites showes its unique properties, we can choose different components of a nanocomposite to endow them some special properties according to the needs of practical application, which make them have excellent comprehensive performance. In recent years, magnetic nanocomposites with different performance have been successively synthesized and widely used in biomedicine, environmental chemistry, sensors, sample separation, analysis and detection, etc. Although a variety of technology and methods has been reported for the preparation of magnetic nanocomposites, most of the preparation methods require toxic or expensive chemical reagent, or the preparation process is relatively complex. At the same time, the obtained magnetic nanocomposites have poor stability, low catalytic activity and cannot satisfy the actual needs. Therefore, developing a simple, green and low-cost method for the preparation of the magnetic nanocomposite is particularly important.Considering the ferroferric oxide nanoparticles (Fe3O4NPs) have superparamagnetism and their surface can be further modified, and gold nanoparticles’(Au NPs) excellent catalytic properties, this dissertation focus on the study of Au doped magnetic multifunctional nanocomposite’s preparation and application, and carried out the following research:1. Based on the unique catalytic properties of Au NPs, a highly efficient catalyst was synthesized by self-assembly and in situ growth of Au NPs on the surface of GO-Fe3O4support. And investigated its catalytic performance, stability, and reuse on the degradation of nitrophenol (4-NP);2. Via electrostatic self-assembly combined with in situ growth method, a multifunctional, core-satellites structural magnetic-Au NPs (Fe3O4@C16@CTS-Au NPs(G)) catalyst was prepared, and its catalytic activity, stability and reuse on degradation of common organic pollutants were studied.This dissertation is divided into three chapters, and a brief introduction is as follows:Chapter1This chapter briefly introduced the development of nanotechnology, magnetic materials, precious metals nanomaterials and the preparation methods of gold doped multifunctional magnetic nanocomposite and their application in various fields.Chapter2In this chapter, the GO-Fe3O4nanocomposite support was synthesized firstly by a one-step method. Then using the APTES to make its surface amination, through self-assembly and in situ growth method, the GO-Fe3O4-Au NPs(G) magnetic nanocomposite was synthesized. Its morphology and structure has been characterized and the stability, reutilization, catalytic performance were investigated. The results have shown that in the presence of NaBH4, the obtained magnetic nanocomposite could effectively catalyse degradation of nitrophenol(an environmental pollutant). The newly prepared catalyst aqueous solution could be stored more than one month and still very stable.In addition, even after runing for10times the catalyst still maintains high catalytic activity.Chapter3The magnetic Fe3O4NPs was prepared by a simple hydrothermal method. The hexadecyl silane was modified on the surface of magnetic Fe3O4NPs to form a fluffy skeleton with high specific surface area. Then the skeleton surface was wrapped with crosslinked with chitosan through crosslinking effect, which is rich in amino functional groups on its surface and hydrophilic. Small Au NPs as Au seeds can anchore on the chitosan surface through static adsorption to form stable core-satellites structure, then HAuCl4was reducted on the surface of the seeds and in situ growth to form Au nanoclusters, finally obtained the Fe3O4@C16@CTS-Au NPs(G) magnetic nanocomposite. The morphology and structure of the Fe3O4@C16@CTS-Au NPs(G) were characterized and the catalytic performance, reutilization, stability were investigated. Results show that in the presence of NaBH4, Fe3O4@C16@CTS-Au NPs(G) can effectively catalyze degradation of some common organic pollutants. The newly prepared catalyst can be stored more than one month and still had good stability, enve after running for eleven times it still maintain excellent catalytic activity. In addition, the nanocomposite has been successfully applied to the degradation of organic pollutants in Yellow River water samples. |
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