RESEARCHER PROFILEFirst Stage Researcher (R1)
APPLICATION DEADLINE11/06/2021 23:59 - Europe/Brussels
LOCATIONFrance › NANTES
TYPE OF CONTRACTTemporary
HOURS PER WEEK35
OFFER STARTING DATE01/10/2021
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.
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). For instance, NPs find their way easily to enter the human body, and may reach the most sensitive organs, disrupting the cell normal biochemical environment. Moreover, there is also a great concern about their ecological risk. NPs 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)). The introduction of such particles into the natural environment could pose a threat to beneficial microbial communities, such as those found in soil (5, 6). Moreover, 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.
To improve environmental risk assessment of NPs, researchers are recommending performing experiments in soils. However, this is extremely complex and difficult to be studied in situ but also in the laboratory as soil constituents (minerals, organic matter, microbes …) can interact with contaminants. For instance, organic matter in soils is known for playing a critical role in the transport and fate of NPs in the environment (7,8) but also the mineral fraction (9). Due to the complexity of soils 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 (10–12). Even though models are often successfully used to fit a specific set of data to obtain meaningful physical and chemical information, there are still limitations with respect to comprehensive predictions of contaminant fate in soils. The transport mechanisms are inferred from particle breakthrough curves (BTCs) measured in the column effluents, which interpretation is likely to be non-unique. Likewise, good agreement between modelled and experimental BTCs may not be sufficient to validate the transport model hypotheses (13).
Originality of the project and objectives:
To overcome the limitations of BTCs analysis, the use of Magnetic Resonance Imaging (MRI) has shown in recent years, as a non-destructive and non-invasive technique, that can produce images inside the soil of both dynamic and static phenomena of NPs during transport experiments (14). However, this has been done in model systems so just taking into account NPs interactions with the mineral part of soils. This can be explained because the addition of soil organic matter (SOM) to model systems will complicate data interpretation and modeling due to the complexity of the interactions with SOM. However, the transport of NPs within in the porous media of a soil is not only affected by the porous network but also by the SOM, which can adsorb them but also increase their transport (15). In particular, Nuclear Magnetic Resonance (NMR) spectroscopy has provided a powerful framework to better understand contaminant fate, bioavailability, toxicity, sequestration and remediation at the molecular level (16). The information gained from “batch” experiments will be applied to the modeling approach.
Another important point of this PhD thesis will be the use of a novel NMR technology termed comprehensive multiphase (CMP)-NMR spectroscopy, which has been recently developed by André Simpson (University of Toronto) in collaboration with Bruker. Traditional NMR technologies namely solution-and solid-state focus on analysis in a single physical state. CMP-NMR can study the different phases such as these found in whole swollen soils and it can obtain different liquid-, gel-and solid-like NMR spectra in a single multiphase sample. In general, the proposed research aims to improve the understanding of NPs transport, and interactions with soil and their impact in water quality in urban soils.
Scientific methodology :
The experimental conditions will be designed to mimic the infiltration of water in urban soils. Nanoparticles 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 in model soils prepared in laboratory columns. The PhD student could benefit from the experimental apparatus to perform experiments in well-controlled conditions. The characterization of the transport and retention processes will be done by MRI and NMR to imaging transport and understanding interactions with SOM respectively.
Porous media with different pore sizes (glass beads, clays ... with added SOM) will be used as model samples to understand this effect on the transport of contaminants into soil. Then, reconstituted soils (used for urban gardens) will be used and real soils at the end. 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.
In the computer simulation part, based on previous our work on model systems (17–20), the impact of physical and/or chemical heterogeneities at the pore size scale will be considered. Particular attention will be paid to the modelling of the influence of physicochemical heterogeneities on electrostatic interactions and on hydrodynamics, which are two of the main processes governing the transport of NPs.
The student will be in charge of performing experiments to mimic the infiltration of runoff waters in basins or irrigation and modelling these data. Nanoparticles will be characterized in terms of size and surface properties (e.g zeta potential). The suspensions will be injected in model soils prepared in laboratory columns. The PhD student could benefit from the experimental apparatus of LEE to perform experiments in well-controlled conditions. The characterization of the retention processes could be done by imaging with MRI and with NMR to imaging transport and understanding interactions with SOM respectively. Moreover, he/she will work on the coupling between physical (water flux and nanoparticles retention processes) and chemical (nanoparticles interactions with SOM) information by and their integration in a numerical code at pore scale on the basis of numerical developments in progress at LEE.
(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) Simonin, M.; Richaume, A. Impact of Engineered Nanoparticles on the Activity, Abundance, and Diversity of Soil Microbial Communities: A Review. Environmental Science and Pollution Research 2015, 22 (18), 13710–13723.
(6) NANOMATERIALS FOR SOIL REMEDIATION; ELSEVIER: S.l., 2021.
(7) Yu, S.; Liu, J.; Yin, Y.; Shen, M. Interactions between Engineered Nanoparticles and Dissolved Organic Matter: A Review on Mechanisms and Environmental Effects. Journal of Environmental Sciences 2018, 63, 198–217.
(8) Sani-Kast, N.; Labille, J.; Ollivier, P.; Slomberg, D.; Hungerbühler, K.; Scheringer, M. A Network Perspective Reveals Decreasing Material Diversity in Studies on Nanoparticle Interactions with Dissolved Organic Matter. Proceedings of the National Academy of Sciences 2017, 114 (10), E1756–E1765. https://doi.org/10.1073/pnas.1608106114.
(9) Wang, R.; Dang, F.; Liu, C.; Wang, D.; Cui, P.; Yan, H.; Zhou, D. Heteroaggregation and Dissolution of Silver Nanoparticles by Iron Oxide Colloids under Environmentally Relevant Conditions. Environmental Science: Nano 2019, 6 (1), 195–206. https://doi.org/10.1039/C8EN00543E.
(10) 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+.
(11) 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.
(12) 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.
(13) 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.
(14) 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.
(15) Cuny, L.; Herrling, M. P.; Guthausen, G.; Horn, H.; Delay, M. Magnetic Resonance Imaging Reveals Detailed Spatial and Temporal Distribution of Iron-Based Nanoparticles Transported through Water-Saturated Porous Media. Journal of Contaminant Hydrology 2015, 182, 51–62. https://doi.org/10.1016/j.jconhyd.2015.08.005.
(16) Simpson, A. J.; Simpson, M. J.; Soong, R. Nuclear Magnetic Resonance Spectroscopy and Its Key Role in Environmental Research. Environmental Science & Technology 2012, 46 (21), 11488–11496. https://doi.org/10.1021/es302154w.
(17) 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.
(18) 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.
(19) 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.
(20) 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.
We seek candidates who demonstrate willingness and ability to study solute transport in complex porous media both on an experimental and modeling point of view. Previous experience with modeling would be highly appreciated. Previous experience with NMR or MRI is not mandatory. The candidates should hold a master degree in physics, fluid mechanics, physical chemistry, environmental sciences, computational sciences, or applied mathematics with excellent grades. Excellent oral and written command of English is required. Curriculum Vitae, cover letter, recommendation letter, transcripts of records relative to the last two years of the Master Degree will be provided in application file.
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YEARS OF RESEARCH EXPERIENCENone
REQUIRED EDUCATION LEVELEngineering: Master Degree or equivalentChemistry: Master Degree or equivalentPhysics: Master Degree or equivalent
REQUIRED LANGUAGESFRENCH: Basic
EURAXESS offer ID: 632122
Posting organisation offer ID: 20925
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