2006 Fiscal Year Final Research Report Summary
Research work of the stabilizing and collapsing mechanism of nano-bubble
| Project/Area Number |
17201028
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nanomaterials/Nanobioscience
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| Research Institution | National Institute of Advanced Industrial Science and Technology (AIST) |
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Principal Investigator |
TAKAHASHI Masayoshi National Institute of Advanced Industrial Science and Technology (AIST), Institute for Environmental Management Technology, Senior researcher, 環境管理技術研究部門, 主任研究員 (00344151)
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| Project Period (FY) |
2005 – 2006
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| Keywords | microbubble / nano-bubble / collapse / free-radicals / salting-out phenomenon / disinfection / physiological activity |
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| Research Abstract |
Nano-bubble is a real new technology developed in research we have been conducting on the collapse of micro-bubbles for a new wastewater treatment method. Nano-bubbles, with diameters less than 1μm, do not ascend perceptibly and stabilize for several months in water. In addition, nano-bubbles show some intriguing properties. Both freshwater and marine fish survived simultaneously for several months in an aquarium filled with water containing oxygen nano-bubbles. Ozone nano-bubbles can be retained for several months in water and have a strong disinfecting ability, as demonstrated by the destruction of viruses inside oyster bodies. In the research we were clarifying the mechanism of stability of the tiny bubbles. Although small bubbles tend to be dissolved in the surrounding water very first, nano-bubbles can be existed for several months in the aqueous solution. As the results, the followings became clear.
* The concentration of the surface electric charge (ions) was confirmed at the col
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lapsing process of the microbubble.
* Free-radicals were generated at the collapsing process.
* The collapsing process is a phenomenon with a temporary break, and this leads to the stabilization of the tiny gas bubble.
* The stabilization of the tiny bubbles was related to the condensed electrolytes surrounding the gas-water interface of the tiny bubble.
* When the nano-bubbles were generated by the forcibly collapsing process, the tiny bubble stabilized for several months in water.
* For mechanism of the stabilization, a salting-out phenomenon with the ion concentration at the surface is regarded as the subject.
* The stabilization of the tiny bubbles might be destroyed by the drastic change of pH of the aqueous solution. About the application of the engineering, big influence was accepted by the germination and initial growth of the seeds such as sprouts Japanese radishes by the oxygen nano bubble. The negative effect of salt for the initial growth tended to be suppressed by the tiny bobbles. By the treatment of atomization of the water containing the ozone nano-bubbles more than 80% of the ability for oxidation was still maintained, and environmental sterilization can be used as a practical application. These results were published or submitted to the science journals such as Journal of Physical Chemistry. Less
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