Analysis of environmental particles by atomic force microscopy, scanning and transmission electron microscopy
Analysis of environmental particles by atomic force microscopy, scanning and transmission electron microscopy
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DOI：
10.2166/wst.2004.0690
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发表时间：
2004-01-01
影响因子：
2.7
通讯作者：
Boller, M
中科院分区：
文献类型：
--
作者：
Mavrocordatos, D;Pronk, W;Boller, M
由于其大的比表面积和丰富的含量，微纳米颗粒在环境中的微污染物的传输中起着重要的作用。天然颗粒通常由无机无定形或结晶材料（主要是FeOOH、FexOy、MnxOy和粘土）和有机材料（腐殖酸和多糖）的混合物组成。它们都倾向于以非常小的颗粒（直径1- 1，000 nm）出现。大多数天然无定形颗粒是不稳定的，并且倾向于随着时间的推移通过老化或可能通过溶解和再结晶而向更多的结晶形式转化。这种转化影响了吸附的微污染物的命运，因此清除性能也发生了变化。由于这些实体对脱水（聚集，形态变化）敏感，因此在其自然环境中观察其形态并了解其在单个颗粒尺度上的组成非常重要。纳米颗粒的存在和行为对于水处理技术的理解和优化也是非常重要的，本文介绍了一些可能的颗粒分析方法：聚集过程、生物矿化、细菌粘附、淡水中的生物膜、水铁矿作为雨水中重金属的去除剂。这些示例展示了显微镜的功能和焦点。原子力显微镜（AFM）允许在其自身环境中分析颗粒，即在空气中或水中。因此，可以观察到颗粒的天然方面。同样，颗粒之间或颗粒与其他表面（如膜）之间的相互作用力将是非常有价值的数据。扫描电子显微镜（SEM）和更高的横向分辨率，透射电子显微镜（TEM）允许测量的形态和组成。特别是，TEM与电子能量损失谱（TEM-EELS）耦合是一种强大的元素分析技术。最后，提供了有效使用显微技术的一般准则。
Due to their large specific surface and their abundance, micro and nano particles play an important role in the transport of micropollutants in the environment. Natural particles are usually composed of a mixture of inorganic amorphous or crystalline material (mainly FeOOH, FexOy, MnxOy and clays) and organic material (humics and polysaccharides). They all tend to occur as very small particles (1-1,000 nm in diameter). Most natural amorphous particles are unstable and tend to transform with time towards more crystalline forms, either by aging or possibly, by dissolution and re-crystallization. Such transformations affect the fate of sorbed micropollutants and the scavenging properties are therefore changed. As these entities are sensitive to dehydration (aggregation, changes in the morphology), it is highly important to observe their morphology in their natural environment and understand their composition at the scale of the individual particles. Also for the understanding and optimization of water treatment technologies, the knowledge of the occurrence and behavior of nano-particles is of high importance.Some of the possible particle analysis methods are presented: aggregation processes, biomineralization, bacterial adhesion, biofilms in freshwaters, ferrihydrite as heavy metals remover from storm water. These examples demonstrate the capabilities and focus of the microscopes. Atomic Force Microscopy (AFM) allows to analyze the particles in their own environment, meaning in air of in the water. Thus, native aspects of particles can be observed. As well, forces of interactions between particles or between particles and other surfaces such as membranes will be highly valuable data. Scanning Electron Microscopy (SEM) and for higher lateral resolution, Transmission Electron Microscopy (TEM) allow measurement of the morphology and composition. Especially, TEM coupled with Electron Energy Loss Spectroscopy (TEM-EELS) is a powerful technique for elemental analysis. Finally, general guidelines for the effective use of microscopic techniques are provided.