Speciation and lability of Ag-, AgCl-, and Ag2S-nanoparticles in soil determined by X-ray absorption spectroscopy and diffusive gradients in thin films.
Speciation and lability of Ag-, AgCl-, and Ag2S-nanoparticles in soil determined by X-ray absorption spectroscopy and diffusive gradients in thin films.
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DOI：
10.1021/es504229h
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发表时间：
2015-01
影响因子：
11.4
通讯作者：
R. Sekine;G. Brunetti;E. Donner;M. Khaksar;K. Vasilev;Å. Jämting;K. Scheckel;P. Kappen;H. Zhang-H.-Zha
中科院分区：
文献类型：
--
作者：
R. Sekine;G. Brunetti;E. Donner;M. Khaksar;K. Vasilev;Å. Jämting;K. Scheckel;P. Kappen;H. Zhang-H.-Zha
通过 X 射线吸收光谱 (XAS) 和新开发的“纳米”薄膜扩散梯度 (DGT) 装置研究了土壤中银 (Ag-)、氯化银 (AgCl-) 和硫化银纳米颗粒 (Ag2S-NP) 的长期形态和稳定性。这些纳米 DGT 设备经过专门设计，以避免在纳米颗粒存在的情况下测量元素不稳定性时出现混杂效应。在长达 7 个月的时间内，在三种不同的土壤 pH 值下检查了土壤中三种纳米颗粒和 AgNO3（离子型银）的老化曲线和稳定性。离子型 Ag、Ag-NP 和 AgCl-NP 的转化取决于 pH 值。在酸性条件下观察到 AgCl 的形成和持久性，而硫结合形式的 Ag 在中性至碱性土壤中占主导地位。人们发现 Ag2S-NP 在所有测试条件下都非常稳定，并且在孵育 7 个月后仍保持硫结合状态。含有Ag2S-NPs 的土壤中Ag 的不稳定性具有较低的特征。其他形式的 Ag 与 DGT 测定的较高不稳定性有关，并且这种不稳定性随着衰老和 XAS 测定的相关形态变化而变化。这些结果清楚地表明，Ag2S-NP 是进入土壤的与环境最相关的银形式，具有化学稳定性，并且在较长时间内具有极低的银不稳定性。这可以最大限度地减少土壤环境中银毒性的长期风险。
Long-term speciation and lability of silver (Ag-), silver chloride (AgCl-), and silver sulfide nanoparticles (Ag2S-NPs) in soil were studied by X-ray absorption spectroscopy (XAS), and newly developed “nano” Diffusive Gradients in Thin Films (DGT) devices. These nano-DGT devices were designed specifically to avoid confounding effects when measuring element lability in the presence of nanoparticles. The aging profile and stabilities of the three nanoparticles and AgNO3 (ionic Ag) in soil were examined at three different soil pH values over a period of up to 7 months. Transformation of ionic Ag, Ag-NP and AgCl-NPs were dependent on pH. AgCl formation and persistence was observed under acidic conditions, whereas sulfur-bound forms of Ag dominated in neutral to alkaline soils. Ag2S-NPs were found to be very stable under all conditions tested and remained sulfur bound after 7 months of incubation. Ag lability was characteristically low in soils containing Ag2S-NPs. Other forms of Ag were linked to higher DGT-determined lability, and this varied as a function of aging and related speciation changes as determined by XAS. These results clearly indicate that Ag2S-NPs, which are the most environmentally relevant form of Ag that enter soils, are chemically stable and have profoundly low Ag lability over extended periods. This may minimize the long-term risks of Ag toxicity in the soil environment.