Preparation, characterization and anti-microbials application of Nanosilver/Clays
| Autor: | Ling-Yi Huang, 黃齡儀 |
|---|---|
| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 Although nanosilver has high anti-microbial capability, the self-aggregation and hard-to-dispersion property of nanosilver render its limitations on the anti-microbial applications. To overcome these problems, natural clays, montmorillonite, were applied as the carrier of nanosilver. Firstly, silver nitrate (AgNO3) was added and the dissociated silver ion would intercalate into the layers of clays. Then a reducing agent, sodium borohydride (NaBH4), was added to reduce silver ions into silver nanoparticles (AgNPs) in the clays. These AgNPs/Clays are expected to contact effectively with microbes to enhance their anti-microbial effects. In this thesis, two modified montmorillonite (CL120 and CL42) with different cation-exchanging capacity were used to prepare the AgNPs/Clay. And XRD, TGA, FT-IR, SEM and TEM are utilized to examine the content, morphology and distribution of nanosilver in AgNPs/Clay. The size of AgNPs ranged from 20 to 50 nm and randomly dispersed in the Clay. The calculated Ag reductant in CL42 and CL120 is 17.1%, 21.5%, 22.5% and 7.9%, 11.0%, 12.7%, respectively. In the microscopic observation of the AgNPs/Clay on E. coli, P. aeruginosa, S. aureus and S. cerevisiae, AgNPs/Clay can severely disrupt the bacteria, but less on yeasts which still maintain their structural integrity. In the aspect of anti-microbial property, E. coli, P. aeruginosa, S. aureus and S. cerevisiae were used to test their anti-microbial effect. The best anti-microbial ability of AgNPs/Clay-CL120 to E. coli, P. aeruginosa, S. aureus and S. cerevisiae is 97.6%, 100%, 52.2%, and 52.8%, respectively. And the anti-microbial effect of AgNPs/Clay-CL42 is 81.5%, 100%, 48.1%, and 24.6%, respectively.These results demonstrated that both kinds of AgNPs/Clays show higher anti-microbial ability to Gram negative bacteria and AgNPs/Clay-CL120 has higher anti-microbial ability than AgNPs/Clay-CL42. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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