【作者】 倪明；

【导师】 何义亮；

【作者基本信息】 上海交通大学 ， 环境工程， 2011， 硕士

【摘要】 纳米技术的迅速发展在带给人类生产和生活巨大变化的同时,其潜在的环境负效应也引起了人们的广泛关注。纳米材料可以通过点源或非点源的途径释放进入到水环境中,其累积浓度随着纳米材料市场的逐渐增大、生产费用的逐渐降低和新产品的不断研发而逐渐增大。富勒烯（fullerene）是被广泛应用在物理化学、材料科学和生物医学等领域的碳纳米材料之一。在种类繁多的富勒烯家族中,C₆₀由于其奇特的物理、化学特性和结构的稳定性,是目前世界各国研究的一种新型纳米材料,其环境安全性日益受到关注。本论文依托国家自然科学基金课题（No. 20907030）,以C₆₀为模型碳纳米材料,研究了其在水介质中的光化学反应活性特征,为深入认识其在环境中的迁移转化特性及生物生态效应提供理论依据。论文主要针对水介质中C₆₀所形成的C₆₀纳米晶体颗粒(nC₆₀)的光化学反应活性进行了三个方面的研究工作:1.采用甲苯置换法及水溶液长期搅拌法制备nC₆₀,并通过透射电子显微镜、动态光散射、和Zeta电位等手段对制备的nC₆₀进行表征;2.探究水介质中nC₆₀的光化学反应活性特征,以及表面活性剂,包括非离子表面活性剂TX-100、TX-405,阳离子表面活性剂CTAB和阴离子表面活性剂SDS及天然有机物（腐植酸）对nC₆₀的光化学反应活性诱导特性和诱导机制,并探索了扩散状态对nC₆₀光化学反应活性产生的影响;3.研究了水介质中nC₆₀对过氧化氢和超氧阴离子自由基参与反应的作用以及环境因素对此作用的影响。论文研究结果表明:1.采用甲苯置换法和水溶液长期搅拌法能够成功制备出nC₆₀。表征结果显示,水介质中nC₆₀呈负电性,表面电位为-46mV,平均粒径约为115nm;2.对nC₆₀的光化学反应活性特征及诱导特性的研究表明,水介质中nC₆₀失去了其在分子态时所具有的光化学反应活性,而非离子表面活性剂TX-100能够诱导其恢复光化学反应活性,且诱导作用与其对nC₆₀的包裹、再分散作用有关;3.在光照条件下,水介质中nC₆₀能够对过氧化氢和超氧阴离子自由基参与的反应产生促进作用,且此作用会受到pH、光照等环境条件和nC₆₀浓度的影响。本课题研究发现了水介质中C₆₀纳米晶体颗粒能够被其共存物质诱导而恢复光化学反应活性,同时对某些氧自由基参与的反应有促进作用,对深入理解其在环境中的生物毒性及迁移转化归趋机制具有重要意义。更多还原

【Abstract】 While the rapid development of nanotechnology brings tremendous change to industrial production, as well as daily life of people, much attention has been paid to its potential negative effect on the environment. Nanomaterials are being discharged from point sources and nonpoint sources into water environment with the expansion of raw material market, the decline of production cost, and the development of new products, resulting in a continuously rising cumulative concentration of nanomaterials in water environment. Fullerenes have been found to have a wide application in the field of physical chemistry, material science and biomedicine so on. C₆₀ is one member of fullerenes. As a novel nanomaterial, C₆₀ has attracted worldwide attention because of its special physical, chemical properties, and its surprisingly stable structure, along with concerns over its environmental security. This research, supported by National Natural Science Foundation of China （No.20907030）, focusing on photochemical properties of nanoscale C₆₀ in water, so as to contribute to further academic study on its transport and transformation fate, and biological and ecological effect.The thesis consists of three main contents with respect to photochemical properties of C₆₀ nanocrystallines (nC₆₀) derived from C₆₀ in water. First, son/nC₆₀ and aqu/nC₆₀ were prepared via toluene solvent- exchange method and stirring method in the aqueous solution, respectively. The prepared nC₆₀ was characterized by TEM and zetasizer. Second, photochemical properties of nC₆₀ aggregates with no coexisting agents, nC₆₀ aggregates dispersed in surfactants （including anion surfactant SDS, cation surfactant CTAB, and non-ion surfactants TX-100 and TX-405）, and nC₆₀ aggregates dispersed in natural organic matter（humic acid）were evaluated. The mechanism of restoration of photochemical properties and the effect of dispersion status of nC₆₀ aggregates on the photochemical properties were explored and analysed. Third, this study evaluated the effect of nC₆₀ aggregates in water on reactions involving H₂O₂ or superoxide radicals, and probed in reaction mechanisms.The following conclusions have been drawn from this research: First, nC₆₀ could be prepared via toluene solvent-exchange method or stirring method in the aqueous solution. nC₆₀ aggregates were verified to be negatively charged, with surface potential of -46mv, and Z-average of 115nm. Second, nC₆₀ aggregates in water were found to be photochemical inert, losing photochemical reactivity that C₆₀ molecules would ever possess. However, photochemical reactivity of nC₆₀ aggregates could be restored by TX-100, which could encapsulate and disperse nC₆₀ aggregates. Third, nC₆₀ aggregates in water was found to have stimulative effect on reactions involving H₂O₂ or superoxide radicals, under UV irradiation, and this effect could be influenced by pH, irradiation intensity, and concentration of nC₆₀ in water.In conclusion, this subject study has demonstrated that photochemical reactivity of nC₆₀ aggregates in water can be restored by certain coexisting agents. And, nC₆₀ aggregates are liable to have stimulative effect on reactions involving certain reactive oxygen species. Such findings would profoundly facilitate understanding of biotoxicity and fate of transformation and transport of nC₆₀ aggregates.更多还原