Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung, Chinese Taiwan.
Water Sci Technol. 2010;61(1):127-33. doi: 10.2166/wst.2010.787.
The application of nanoparticles in the processes of making commercial products has increased in recent years due to their unique physical and chemical properties. With increasing amount of commercial nanoparticles released into nature, their fate and effects on the ecosystem and human health are of growing concern. This study investigated the stability and morphology of three metal oxide nanoparticles in aqueous solutions. The commercially available nanoparticles, TiO(2), ZnO, SiO(2), aggregated quickly into micrometer-size particles in aqueous solutions, which may not threaten human health. Their changes in morphology and characteristics were further examined by dynamic light scattering (DLS) method and transmission electron microscopy (TEM). Among the several dispersion approaches, ultrasonication was found to be the most effective for disaggregating nanoparticles in water. For these three selected nanoparticles, ZnO could not remain stable in suspensions, presumably due to the dissolution of particles to form high concentration of ions, resulting in enhanced aggregation of particles. In addition, the existence of dissolved organic matters stabilized nanoparticles in lake water and wastewater for several hours in spite of the high concentration of cations in these real-water samples. The fate of metal oxide nanoparticles in natural water bodies would be determined by the type and concentration of cations and organic matters. Results obtained in this study revealed that the stability of nanoparticles changed under different aqueous conditions and so did their fate in the environment.
近年来，由于纳米粒子具有独特的物理和化学性质，其在商业产品制造过程中的应用有所增加。随着越来越多的商业纳米粒子被释放到自然界中，它们对生态系统和人类健康的命运和影响引起了越来越多的关注。本研究调查了三种金属氧化物纳米粒子在水溶液中的稳定性和形态。市售的纳米粒子 TiO(2)、ZnO 和 SiO(2)在水溶液中迅速聚集成长为微米级颗粒，这可能不会对人体健康构成威胁。通过动态光散射 (DLS) 方法和透射电子显微镜 (TEM) 进一步研究了它们的形态和特性变化。在几种分散方法中，发现超声处理最有效地将纳米粒子在水中解团聚。对于这三种选定的纳米粒子，ZnO 不能在悬浮液中保持稳定，可能是由于颗粒溶解形成高浓度离子，导致颗粒聚集增强。此外，尽管这些实际水样中的阳离子浓度很高，但溶解的有机物仍能使纳米粒子在湖水和废水中稳定存在数小时。金属氧化物纳米粒子在天然水体中的命运将取决于阳离子和有机物的类型和浓度。本研究的结果表明，纳米粒子在不同的水相条件下稳定性发生变化，因此它们在环境中的命运也会发生变化。
