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Engineered nanoparticles (ENPs), defined by their nanoscale size (<100 nm) and high specific surface area, exhibit unique physicochemical properties that enable widespread applications in fields such as biomedicine, catalysis, electronics, energy, and environmental technologies (Nowack & Bucheli, 2007). However, their increasing release into the environment raises concerns regarding their potential risks to ecosystems and groundwater systems. Understanding the transport of ENPs in porous media is therefore essential for predicting their environmental fate. While previous studies have investigated nanoparticle transport in the presence of dissolved organic matter (Fazeli Sangani et al., 2018), only a limited number of studies have considered model porous media with immobilized organic coatings, such as humic acid (HA)–coated sand (Wang et al., 2022), resulting in significant knowledge gaps regarding nanoparticle behavior in more realistic soil systems. In this study, nanoparticle interactions with modified porous media will be investigated with a focus on particle–scale processes. Surface-functionalized gold nanoparticles (AuNPs) with contrasting surface charges will be employed to examine the role of particle–surface interactions. Single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) will be applied as a key analytical tool, enabling the determination of particle number concentrations and size distributions.
Porous media were modified through HA–coating to represent surface–bound organic matter in natural systems (Wang et al., 2022; Yin et al., 2019; Zhuang & Jin, 2003). The coated media were characterized using scanning electron microscopy and an energy dispersive spectrometer (SEM–EDS) to confirm the presence of organic layers on sand surfaces. The amount of coating and its stability were evaluated using total organic carbon (TOC) measurements in solid and liquid phases, respectively. Batch experiments are being conducted to investigate nanoparticle interactions with coated media, with sp-ICP-MS enabling size–resolved analysis of particle number concentrations and distributions.
First results confirm the successful formation of HA–coatings on sand surfaces, as evidenced by SEM–EDS analysis. The amount of organic coating was quantified at approximately 1 g C/kg of dry material. Stability tests indicate that the HA–coating is largely stable under aqueous conditions, with less than 10% release of loosely bound organic matter. Transport experiments will allow us to assess size-dependent nanoparticle mobility and evaluate how particle properties, including size and surface charge, influence transport behavior in model porous media.
These findings demonstrate that HA–coated porous media can be reliably prepared and remain largely stable under aqueous conditions, providing a suitable model system for investigating nanoparticle interactions. Additional surface modifications, including mineral and organo–mineral coatings, are being explored to assess the role of surface heterogeneity. The integration of sp-ICP-MS will enable a size-resolved characterization of nanoparticle populations, offering new opportunities to investigate size-dependent transport behavior. Future work will further examine the role of nanoparticle surface charge in controlling particle–surface interactions and transport dynamics. This work should establish a foundation for size-resolved studies of nanoparticle transport in model porous media with controlled conditions.
| References | Fazeli Sangani, M., Owens, G., & Fotovat, A. (2018). Transport of engineered nanoparticles in soils and aquifers. Https://Doi.Org/10.1139/Er-2018-0022, 27(1), 43–70. https://doi.org/10.1139/ER-2018-0022 Nowack, B., & Bucheli, T. D. (2007). Occurrence, behavior and effects of nanoparticles in the environment. Environmental Pollution, 150(1), 5–22. https://doi.org/10.1016/J.ENVPOL.2007.06.006 Wang, K., Ma, Y., Sun, B., Yang, Y., Zhang, Y., & Zhu, L. (2022). Transport of silver nanoparticles coated with polyvinylpyrrolidone of various molecular sizes in porous media: Interplay of polymeric coatings and chemically heterogeneous surfaces. Journal of Hazardous Materials, 429, 128247. https://doi.org/10.1016/J.JHAZMAT.2022.128247 Yin, X., Jiang, Y., Tan, Y., Meng, X., Sun, H., & Wang, N. (2019). Co-transport of graphene oxide and heavy metal ions in surface-modified porous media. Chemosphere, 218(11), 1–13. https://doi.org/10.1016/j.chemosphere.2018.11.089 Zhuang, J., & Jin, Y. (2003). Virus Retention and Transport as Influenced by Different Forms of Soil Organic Matter. Journal of Environmental Quality, 32(3), 816–823. https://doi.org/10.2134/JEQ2003.8160;WEBSITE:WEBSITE:ACSESS.ONLINELIBRARY.WILEY.COM;WGROUP:STRING:PUBLICATION |
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| Country | France |
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