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Silver nanoparticle (Ag-NP) retention and release in partially saturated soil: column experiments and modelling†
Environmental Science: Nano ( IF 7.3 ) Pub Date : 2017-12-08 00:00:00 , DOI: 10.1039/c7en00990a
Yinon Yecheskel 1, 2, 3, 4 , Ishai Dror 1, 2, 3, 4 , Brian Berkowitz 1, 2, 3, 4
Affiliation  

The need for better understanding of the environmental fate and transport of engineered nanoparticles (ENPs) is now a scientific consensus. However, the partially saturated zone, a critical region that links the earth's surface to aquifers, has to date received only minor attention in the context of ENP mobility. We investigate the transport and fate of a representative ENP, silver nanoparticles (Ag-NPs), in partially saturated soil. Here we present a set of column experiments and modelling simulations to examine breakthrough curves (BTCs), retention profiles, and mass balances that characterize Ag-NP transport, and gain insights into retardation mechanisms. Unlike Ag-NP transport in sand columns, where the BTC pattern often resembles that of a conservative tracer, Ag-NP transport in soil columns shows moderate mobility and more complex BTC patterns; these results also emphasize the importance of employing realistic porous media in environmental studies. Overall, Ag-NP mobility decreases in the presence of Ca(NO3)2, and increases when the solution contains humic acid, at higher water saturation levels, or at higher input concentrations of Ag-NPs. In addition, a different pattern was observed for Ag-NP aggregates, indicating nanospecific behaviour. Modelling analysis of Ag-NP transport in partially saturated soil suggests that a two-site kinetic model with a time-dependent retention function quantifies the transport behaviour of Ag-NPs.

中文翻译:

银纳米颗粒(Ag-NP)在部分饱和土壤中的保留和释放:色谱柱实验和建模

现在,需要更好地了解工程纳米颗粒(ENP)的环境命运和运输已成为科学共识。但是,在ENP流动性的背景下,部分饱和带是将地球表面与含水层连接起来的关键区域,迄今只受到了很少的关注。我们研究了部分饱和土壤中具有代表性的ENP银纳米颗粒(Ag-NPs)的运输和命运。在这里,我们介绍了一组柱实验和建模模拟,以检查表征Ag-NP转运的突破曲线(BTC),保留曲线和质量平衡,并深入了解阻滞机理。与砂柱中Ag-NP的运输不同,BTC模式通常类似于保守示踪剂的模式,Ag-NP在土壤柱中的迁移显示出中等的迁移率和更复杂的BTC模式。这些结果也强调了在环境研究中采用现实的多孔介质的重要性。总体而言,在Ca(NO3 2,并且在溶液中含有腐殖酸,更高的水饱和度或更高的Ag-NPs输入浓度时增加。另外,对于Ag-NP聚集体观察到不同的模式,表明纳米特异性行为。Ag-NP在部分饱和土壤中的迁移的模型分析表明,具有时变保留函数的两点动力学模型量化了Ag-NPs的迁移行为。
更新日期:2017-12-08
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