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Reference : FR2488-BEABEC1-002
Workplace : BOUGUENAIS
Date of publication : Wednesday, July 21, 2021
Scientific Responsible name : Denis COURTIER-MURIAS
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 4 October 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Nanoparticles (NPs), emerging pollutants and tiny particles under 100 nanometres in size, represent a special threat due to the broad and efficient application within modern technologies (1-3). They can enter the soil through industrial spills but they can also be used intentionally to clean the soil (e.g. they have been used to remove a range of pollutants from soil (4)). Models suggest that soil is a major receptor of NPs —more so than air or water but NPs can also infiltrate through the vadose zone to the water-table and the groundwater flow.
Due to the complexity of soils (minerals, organic matter, microbes …) and the technical difficulties to measure soil contamination in situ, many powerful environmental models predicting the fate and transport of contaminants in soils are being developed (5–7). However, there are still limitations with respect to comprehensive predictions of contaminant fate in soils. For instance, the transport mechanisms are inferred from particle breakthrough curves (BTCs) measured in the column effluents, which interpretation is likely to be non-unique (8).
Originality of the project:
To better analyze BTCs data, we have used during recent years Magnetic Resonance Imaging (MRI) to obtain images inside the studied samples to observe both dynamic and static phenomena of NPs during transport experiments (9). However, this has been done in model systems (mineral part of soils) without taking into account the interactions with soil organic matter (SOM). In this project, we will study the interactions between NPs and SOM in systems of different complexity (up to real soils) in order to be able to better modeling the transport of NPs in real soils.
The experimental conditions will be designed to mimic the interactions of NPs in urban soils. NPs will be prepared and characterized in terms of size and surface properties (e.g zeta potential, single particle inductively coupled plasma mass spectrometry (spICP-MS)). The suspensions will be injected soils of different complexity (up to real soils) prepared in the laboratory. In addition, the characterization of the retention process will be done by NMR to understand the interactions with SOM at the molecular level. The NMR part will be carried out by supervising Master students with model samples (e.g. humic acids, IHSS soils), and then it will be applied by the PhD student in real soils by collaborating with the University of Toronto (trips of about 3 weeks each year). Moreover, NPs with different functional groups will be used to investigate the consequence of adsorption of contaminants into the well characterized porous surface. Finally, soils samples with different textures (which have already been well characterized by our team) will be used.
(1) Hagens, W. I.; Oomen, A. G.; de Jong, W. H.; Cassee, F. R.; Sips, A. J. A. M. What Do We (Need to) Know about the Kinetic Properties of Nanoparticles in the Body? Regulatory Toxicology and Pharmacology 2007, 49 (3), 217–229.
(2) Nemmar, A.; Hoet, P. H. M.; Vanquickenborne, B.; Dinsdale, D.; Thomeer, M.; Hoylaerts, M. F.; Vanbilloen, H.; Mortelmans, L.;Nemery, B. Passage of Inhaled Particles Into the Blood Circulation in Humans. Circulation 2002, 105 (4), 411–414.
(3) Takenaka, S.; Karg, E.; Roth, C.; Schulz, H.; Ziesenis, A.; Heinzmann, U.; Schramel, P.; Heyder, J. Pulmonary and Systemic Distribution of Inhaled Ultrafine Silver Particles in Rats. Environmental Health Perspectives 2001, 109 (suppl 4), 547–551. https://doi.org/10.1289/ehp.01109s4547.
(4) Araújo, R.; Castro, A. C. M.; Fiúza, A. The Use of Nanoparticles in Soil and Water Remediation Processes. Materials Today: Proceedings 2015, 2 (1), 315–320. https://doi.org/10.1016/j.matpr.2015.04.055.
(5) Alexander, M. Aging, Bioavailability, and Overestimation of Risk from Environmental Pollutants. Environmental Science &Technology 2000, 34 (20), 4259–4265. https://doi.org/10.1021/es001069+.
(6) McGinley, P. M.; Katz, L. E.; Weber, W. J. A Distributed Reactivity Model for Sorption by Soils and Sediments. 2.Multicomponent Systems and Competitive Effects. Environmental Science & Technology 1993, 27 (8), 1524–1531.
(7) Lafolie, F.; Hayot, C.; Schweich, D. Experiments on Solute Transport in Aggregated Porous Media: Are Diffusions Within Aggregates and Hydrodynamic Dispersion Independent? Transport in Porous Media 1997, 29 (3), 281–307.
(8) Tufenkji, N.; Elimelech, M. Breakdown of Colloid Filtration Theory: Role of the Secondary Energy Minimum and Surface Charge Heterogeneities. Langmuir 2005, 21 (3), 841–852. https://doi.org/10.1021/la048102g.
(9) Nestle, N.; Baumann, T.; Niessner, R. Peer Reviewed: Magnetic Resonance Imaging in Environmental Science. Environmental Science & Technology 2002, 36 (7), 154A-160A. https://doi.org/10.1021/es0222723.
(10) Courtier-Murias, D.; Michel, E.; Rodts, S.; Lafolie, F. Novel Experimental–Modeling Approach for Characterizing Perfluorinated Surfactants in Soils. Environ. Sci. Technol. 2017, 51 (5), 2602–2610. https://doi.org/10.1021/acs.est.6b05671.
(11) Lehoux, A. P.; Faure, P.; Michel, E.; Courtier-Murias, D.; Rodts, S.; Coussot, P. Transport and Adsorption of Nano-Colloids in Porous Media Observed by Magnetic Resonance Imaging. Transport in Porous Media 2017, 119 (2), 403–423.
(12) Lehoux, A. P.; Faure, P.; Lafolie, F.; Rodts, S.; Courtier-Murias, D.; Coussot, P.; Michel, E. Combined Time-Lapse Magnetic Resonance Imaging and Modeling to Investigate Colloid Deposition and Transport in Porous Media. Water Research 2017, 123,12–20. https://doi.org/10.1016/j.watres.2017.06.035.
(13) Lehoux, A. P.; Rodts, S.; Faure, P.; Michel, E.; Courtier-Murias, D.; Coussot, P. Magnetic Resonance Imaging Measurements Evidence Weak Dispersion in Homogeneous Porous Media. Physical Review E 2016, 94 (5). https://doi.org/10.1103/PhysRevE.94.053107.
This thesis will be developed within the framework of a Research Collaboration Program between University of Toronto (UofT) and the “Centre National de la Recherche Scientifique” (CNRS). This thesis work will be supervised at the Eau et Environnement Laboratoire (LEE) from Université Gustave Eiffel (UGE) at Nantes campus and the Institut de Recherche en Sciences et Techniques de la Ville (IRSTV, FR2488). Moreover, the PhD student will expend 3 weeks each year at the University of Toronto. In addition, the PhD student will beneficiate from the information gained from another part of this Research Collaboration Program. A PhD student from UofT will be able to work with two French recognized experts in NMR (Jonathan Farjon, CEISAM, and Denis Courtier-Murias, LEE) on developing multi-scale (high and low field) liquid NMR as well as solid NMR experiments and also low field MRI (1D profiles) experiments to study NPs interactions with SOM.
Constraints and risks
Application file : curriculum Vitae, cover letter, recommendation letter, transcripts of records relative to the last two years of the Master Degree
Expected skills : environmental chemistry, solid physico-chemistry, spectroscopic and chemical analytical methods. An experience in NMR would be a plus but is not required. A strong interest in environmental issues is required.
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