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Description
The broad application of engineered nanoparticles in various fields leads to their inevitable release into the natural environment, causing soil and groundwater contamination. Bacteria, ubiquitous in the subsurface, can alter the transport behavior of nanoparticles. Hence, it is imperative to understand the interactions between nanoparticles and bacteria in the subsurface to protect drinking water wells from contamination. This study investigated the cotransport of metal oxide nanoparticle aggregates (zinc oxide, nZnO, and titanium dioxide, nTiO2) with E. coli in saturated porous media in 1 mM NaCl and pH 8 under various flow velocities (0.26 - 1.02 cm/min) through column experiments and mathematical modeling. The injection concentrations of nanoparticles and E. coli were 15 mg/L and 107 CFU/mL, respectively. We observed enhanced transport of nZnO and nTiO2 and reduced transport of E. coli during their cotransport compared to nanoparticle-only and E. coli-only transport. The contrasting transport behaviors of nanoparticles and E. coli are due to the formation of nanoparticle-E. coli heteroaggregates, which have different transport properties than free nanoparticles and E. coli, and the preferential attachment of nanoparticles over E. coli to sand surfaces. Further, nZnO transport was enhanced to a greater extent than nTiO2 transport due to the greater rate of heteroaggregation of nZnO and E. coli in comparison to nTiO2 and E. coli. The experimental results were successfully simulated using a model that accounted for the kinetics of heteroaggregation of nanoparticles and E. coli, and heteroaggregate retention in sand.
Keywords: Metal oxide nanoparticles; Escherichia coli; sand; heteroaggregate; two-way coupled model
| References | [1] Manik, R., Seetha, N., Deeksha, W., & Rajakumara, E. (2025). Cotransport of zinc oxide and titanium dioxide nanoparticle aggregates with bacteria in saturated porous media: A coupled experimental and modeling approach. Journal of Hazardous Materials, 139941. https://doi.org/10.1016/j.jhazmat.2025.139941 [2] Seetha, N., & Hassanizadeh, S. M. (2022). A two-way coupled model for the co-transport of two different colloids in porous media. Journal of Contaminant Hydrology, 244, 103922. https://doi.org/10.1016/j.jconhyd.2021.103922 [3] Xu, N., Cheng, X., Wang, D., Xu, X., Huangfu, X., & Li, Z. (2018). Effects of Escherichia coli and phosphate on the transport of titanium dioxide nanoparticles in heterogeneous porous media. Water Research, 146, 264–274. https://doi.org/10.1016/j.watres.2018.09.047 |
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| Country | India |
| Green Housing & Porous Media Focused Abstracts | This abstract is related to Green Housing |
| Student Awards | I would like to submit this presentation into the Earth Energy Science (EES) and Capillarity Student Poster Awards. |
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