State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
Bren School of Environmental Science and Management, University of California, Santa Barbara, CA, 93106, USA.
Adv Colloid Interface Sci. 2015 Dec;226(Pt A):24-36. doi: 10.1016/j.cis.2015.07.002. Epub 2015 Jul 22.
The application of nanoparticles has raised concern over the safety of these materials to human health and the ecosystem. After release into an aquatic environment, nanoparticles are likely to experience heteroaggregation with biocolloids, geocolloids, natural organic matter (NOM) and other types of nanoparticles. Heteroaggregation is of vital importance for determining the fate and transport of nanoparticles in aqueous phase and sediments. In this article, we review the typical cases of heteroaggregation between nanoparticles and biocolloids and/or geocolloids, mechanisms, modeling, and important indicators used to determine heteroaggregation in aqueous phase. The major mechanisms of heteroaggregation include electric force, bridging, hydrogen bonding, and chemical bonding. The modeling of heteroaggregation typically considers DLVO, X-DLVO, and fractal dimension. The major indicators for studying heteroaggregation of nanoparticles include surface charge measurements, size measurements, observation of morphology of particles and aggregates, and heteroaggregation rate determination. In the end, we summarize the research challenges and perspective for the heteroaggregation of nanoparticles, such as the determination of αhetero values and heteroaggregation rates; more accurate analytical methods instead of DLS for heteroaggregation measurements; sensitive analytical techniques to measure low concentrations of nanoparticles in heteroaggregation systems; appropriate characterization of NOM at the molecular level to understand the structures and fractionation of NOM; effects of different types, concentrations, and fractions of NOM on the heteroaggregation of nanoparticles; the quantitative adsorption and desorption of NOM onto the surface of nanoparticles and heteroaggregates; and a better understanding of the fundamental mechanisms and modeling of heteroaggregation in natural water which is a complex system containing NOM, nanoparticles, biocolloids and geocolloids.
纳米颗粒的应用引起了人们对这些材料对人类健康和生态系统安全性的关注。纳米颗粒释放到水生环境后,很可能与生物胶体、地质胶体、天然有机物(NOM)和其他类型的纳米颗粒发生异质聚集。异质聚集对于确定纳米颗粒在水相和沉积物中的命运和传输至关重要。本文综述了纳米颗粒与生物胶体和/或地质胶体之间异质聚集的典型案例、机制、模型以及用于确定水相异质聚集的重要指标。异质聚集的主要机制包括电力、桥接、氢键和化学键。异质聚集的建模通常考虑 DLVO、X-DLVO 和分形维数。研究纳米颗粒异质聚集的主要指标包括表面电荷测量、粒径测量、颗粒和聚集体形态观察以及异质聚集速率测定。最后,我们总结了纳米颗粒异质聚集的研究挑战和展望,例如确定α hetero 值和异质聚集速率;更准确的分析方法代替 DLS 进行异质聚集测量;在异质聚集体系中测量低浓度纳米颗粒的敏感分析技术;在分子水平上适当表征 NOM 以了解 NOM 的结构和分馏;不同类型、浓度和分数的 NOM 对纳米颗粒异质聚集的影响;NOM 在纳米颗粒和异质聚集体表面的定量吸附和解吸;以及更好地理解含有 NOM、纳米颗粒、生物胶体和地质胶体的复杂天然水系统中的异质聚集基本机制和建模。