State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control, Department of Environmental Science & Engineering, North China Electric Power University, Baoding 071000, China.
J Environ Sci (China). 2023 Aug;130:14-23. doi: 10.1016/j.jes.2022.10.025. Epub 2022 Oct 25.
The application of selenium nanoparticles (SeNPs) as nanofertilizers may lead to the release of SeNPs into aquatic systems. However, the environmental behavior of SeNPs is rarely studied. In this study, using alginate-coated SeNPs (Alg-SeNPs) and polyvinyl alcohol-coated SeNPs (PVA-SeNPs) as models, we systematically investigated the aggregation and stability of SeNPs under various water conditions. PVA-SeNPs were highly stable in mono- and polyvalent electrolytes, probably due to the strong steric hindrance of the capping agent. Alg-SeNPs only suffered from a limited increase in size, even at 2500 mmol/L NaCl and 200 mmol/L MgCl, while they underwent apparent aggregation in CaCl and LaCl solutions. The binding of Ca and La with the guluronic acid part in alginate induced the formation of cross-linking aggregates. Natural organic matter enhanced the stability of Alg-SeNPs in monovalent electrolytes, while accelerated the attachment of Alg-SeNPs in polyvalent electrolytes, due to the cation bridge effects. The long-term stability of SeNPs in natural water showed that the aggregation sizes of Alg-SeNPs and PVA-SeNPs increased to several hundreds of nanometers or above 10 µm after 30 days, implying that SeNPs may be suspended in the water column or further settle down, depending on the surrounding water chemistry. The study may contribute to the deep insight into the fate and mobility of SeNPs in the aquatic environment. The varying fate of SeNPs in different natural waters also suggests that the risks of SeNPs to organisms living in diverse depths in the aquatic compartment should be concerned.
硒纳米颗粒（SeNPs）作为纳米肥料的应用可能导致 SeNPs 释放到水生系统中。然而，SeNPs 的环境行为很少被研究。在这项研究中，我们使用海藻酸钠包覆的硒纳米颗粒（Alg-SeNPs）和聚乙烯醇包覆的硒纳米颗粒（PVA-SeNPs）作为模型，系统地研究了 SeNPs 在各种水条件下的聚集和稳定性。PVA-SeNPs 在单价和多价电解质中高度稳定，这可能是由于包覆剂的强大空间位阻。Alg-SeNPs 仅在 2500mmol/L NaCl 和 200mmol/L MgCl 下尺寸略有增加，而在 CaCl 和 LaCl 溶液中则明显聚集。钙和镧与海藻酸钠中的古洛糖醛酸部分结合诱导交联聚集的形成。天然有机物增强了 Alg-SeNPs 在单价电解质中的稳定性，同时加速了 Alg-SeNPs 在多价电解质中的附着，这是由于阳离子桥接效应。SeNPs 在天然水中的长期稳定性表明，Alg-SeNPs 和 PVA-SeNPs 的聚集尺寸在 30 天后增加到几百纳米或 10μm 以上，这意味着 SeNPs 可能悬浮在水柱中或进一步沉降，这取决于周围的水化学。该研究可能有助于深入了解 SeNPs 在水生环境中的归宿和迁移性。SeNPs 在不同天然水中的不同归宿也表明，应该关注 SeNPs 对生活在水生环境中不同深度的生物的风险。
