| Budget Amount *help |
¥18,440,000 (Direct Cost: ¥15,500,000、Indirect Cost: ¥2,940,000)
Fiscal Year 2009: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2008: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2007: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2006: ¥5,700,000 (Direct Cost: ¥5,700,000)
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| Research Abstract |
In this study, novel adsorbents using nano-sized materials as the functioning sites for elimination of toxic chemicals from contaminated environmental samples have been established. First, as-received carbon nanotubes (CNTs) were used as absorbing sites and the study was focusing on evaluating the mechanism of absorbing volatile organic compounds (VOCs) with 23 VOCs as the targets. CNTs showed high selectivity and high affinity for absorbing aromatic VOCs (benzene, toluene, m-xylene, p-xylene, o-xylene, and p-dichlorobenezen). A model based on Fukui's frontier theory was proposed for explaining the adsorption mechanism. Next, CNTs of agglomerated forms were dispersed into individual tubes. The resultant dispersed-CNTs were inserted into cavities of diatomite to form composites of diatomite/CNTs. These composites were finally immobilized onto the cell walls of flexible polyurethane foams (PUF) through an in situ PUF formation process to produce the foam-like CNT-based adsorbent. Water-s
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oluble organic dyes were selected as the targeted chemicals for studying the adsorptive capabilities of the foam-like CNT-based adsorbent. The foam-like CNT-based adsorbents were found to have higher adsorptive capacities than the CNT agglomerates for all five dyes ; in addition, they are macro-sized, durable, flexible, hydrophilic and easy to use. Adsorption isotherms plotted based on the Langmuir equation gave linear results, suggesting that the foam-like CNT-based adsorbent functioned in the Langmuir adsorption manner. Moreover, in this study, double-helix DNA and sodium alginate, the naturally occurred nano-sized materials were also used as the functioning sites for building up the novel adsorbents for elimination of toxic chemicals. A novel approach by encapsulation of the absorbing sites based on in situation formation of polyurethane foams was developed. The adsorbent with DNA as the functioning site has shown high ability for absorbing chemicals of planar structures, such ethidium bromide based on intercalation interactions. While, the adsorbents with sodium alginate as the functioning sites has shown high selectivity for lead (II) ions with the chelating interaction as the dominating absorbing mechanism. Finally, in this study, evaluation of the possible toxicity of CNTs on rice cells and on Arabidopsis T87 suspension cells has also been carried out. Less
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