Reference : UPR3407-ARLVEG-002
Workplace : VILLETANEUSE
Date of publication : Tuesday, May 10, 2022
Scientific Responsible name : Arlette VEGA-GONZALEZ
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 3 October 2022
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
-Per- and poly-fluoroalkyl substances (PFAS) are anthropogenic chemicals that have been widely used in consumer and industrial products. Throughout their production, application, and waste disposal, these chemicals are discharged into the environment, where their persistence leads to major environmental and health issues. Over the last decade, the United States and the European Union have regulated or limited the production of PFOA and PFOS, and set a health advisory concentration for these compounds in drinking water (US EPA 70 ng/L; EU Drinking Water Directive, 0.5µg/L for total PFAS concentration). Because PFAS' stable and strong C-F bonds provide extreme thermal and chemical stability, they show high resistance to degradation. Despite the fact that sorption- and membrane-based processes are effective in controlling these contaminants, they do not destroy PFAS. Thus, further in-situ treatment is needed and novel destructive techniques for PFAS removal, such as electric discharges (plasmas) generated directly into contaminated water, are an interesting option for the treatment of water containing these emergent pollutants.
The use of OH radicals (•OH), which have high oxidation potential, is a promising option for the treatment of persistent organic compounds. Applying the Plasma-Liquid Interaction (PLI) process to an aqueous solution will cause the formation of radicals and ions such as •OH, •H, H2O+ and e-. From an environmental point of view, PLI techniques at Patm/Tamb are promising not only because of their low energy consumption, but above all because of their capacity to generate such highly reactive species offering the possibility of having a rather complex chemistry, while limiting the use of solvents and other chemical products. It is particularly this last point which justifies the adoption of this technique for PFAS degradation.
The objective of this thesis will be, in a first step, to develop a plasma process generated in a liquid medium containing PFAs, based on previous work of the LSPM. Secondly, the study will consist in the implementation of a new method to follow the evolution of the model compound concentration during the PLI process; this study will be carried out in collaboration with the University of Chicago. Finally, the thesis work will focus on the evaluation of the efficiency of a PLI process in the degradation of two model PFAs, by studying the opportunities of optimization of the process (gap distance, voltage polarity, discharge duration, frequency, temperature, etc.).
The PhD work will be carried out in the team “Polyphasic Plasma Processes for the Environment - 3PE” of the Laboratoire des Sciences des Matériaux et des Procédés (LSPM). The PhD student will be co-supervised by two researchers.
This research project is the result of an application to the Joint Call for Proposals in 2021-2022 Research Collaboration Program between the University of Chicago and the Centre National de la Recherche Scientifique (CNRS). It involves three major institutions: CNRS, University of Chicago and Argonne National Laboratory (https://pme.uchicago.edu/ ; https://www.anl.gov/). Thus, during the 3-years period of the PhD, a stay of several weeks in the UChicago/Argonne laboratory is planned each year.
Applicants must hold a Master's degree (or be about to earn one) or have a university degree equivalent to a European Master's (5-year duration) in chemistry, environmental chemistry/electrochemistry, chemical ecology or closely related sciences. A background in physicochemical analysis techniques is desirable.
The applicant should have a strong motivation for experimental work (including strong skills for data synthesis and analysis), strong organizational skills, and must be able to communicate fluently in English.
Applications should include a detailed CV, two references, a letter of motivation, a summary of the Master's internship, as well as the grades of Master 1 and 2.
Application deadline: May 31, 2022
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