Development of functionalized supports for the decontamination of complex surfaces contaminated by chemical agents

In the case of contamination by a toxic chemical agent, treatment begins with rapid emergency decontamination. Those working in the field must take into account the risk of contamination transfer, in particular by wearing suitable protective clothing. These clothing, as well as the small equipment used, must then be decontaminated before considering undressing to avoid self-contamination. The procedure includes a “dry” decontamination phase generally by applying powders (often clays) which are then wiped off using a glove or sponge. However, this device does not neutralize chemical contaminants and the powder re-aerosolizes easily, so its use is limited to unconfined and ventilated environments. The objective of this thesis is to develop an alternative technology for the decontamination of complex surfaces (clothing, small equipment). We propose to study the functionalization of different supports (such as gloves, wipes, microfibers, sponges, hydrogels, etc.) by adsorbent particles (zeolites, ceramic oxides, MOFs, etc.). A preliminary bibliographic study will allow us to select the most suitable adsorbents and supports for the capture of model chemical agents. The work will focus on the preparation of the supports, and different ways of incorporation of the particles in/on these supports will be compared. The materials will be characterized (incorporation rate, homogeneity, mechanical strength, non-reaerosolization, etc.), then their transfer, sorption and inactivation properties will be evaluated with model molecules.

This subject is aimed at dynamic chemists, motivated by the multidisciplinarity (chemistry of mineral and/or polymer materials, solid characterization and analytical chemistry), and having a particular interest in the development of experimental devices. The candidate will work within the Supercritical Processes and Decontamination Laboratory at the Marcoule site, and will benefit from the laboratory's expertise in decontamination and the development of adsorbent materials, as well as the support and expertise of the ICGM institut in Montpellier on functional polymers and hydrogels. The student will interact with the laboratory's technicians, engineers, doctoral students and post-doctoral fellows. The doctoral student will be involved in the different stages of the project, the reporting and publication of its results, and the presentation of its work in conferences. He/She will develop solid knowledge in the fields of nuclear and environmental science, as well as in project management.

Elaboration and durability evaluation of water-permselective multilayer membranes for the CO2 conversion into e-fuels

The catalytic hydrogenation of CO2 into e-fuels is considered to decarbonize certain modes of transport that are difficult to electrify. However, some of the considered reactions are thermodynamically balanced (limited CO2 conversion efficiencies) and catalyst degradation by the produced water is observed. The use of membrane reactors, allowing water separation, is envisaged. For this, the development of water-permselective membranes, without defects and resistant to synthesis conditions, is necessary. Previous studies have targeted LTA and SOD zeolite membranes for this application. However, the presence of defects reduces their selectivity, and their performance deteriorates during operation. The objective of this thesis is therefore to study the sealing of membrane defects and the deposition of protective layers on their surface to improve their performance and durability. To achieve this, the deposition of permselective zeolite layers will first be carried out hydrothermally on suitable porous supports. The sealing of defects by impregnation/conversion of silica precursors in a supercritical CO2 environment will then be studied. Finally, different protective layers (zeolite, ceramic oxide, etc.) will be deposited on the membranes (sol-gel, supercritical CO2, hydrothermal methods). The coatings will be characterized (XRD, SEM, porosimetry, elipsometry, etc.) to ensure their chemical nature, thickness/homogeneity, and porosity. Gas permeation performance will be evaluated at the various stages of preparation, and the durability of the membranes will be studied in the presence of water vapor at different temperatures.
The candidate will work within the Supercritical Processes and Decontamination Laboratory (Marcoule), and will benefit from the laboratory's expertise in ceramic membranes. The student will interact with the laboratory's technicians, engineers, doctoral students and post-doctoral fellows and will exchange with the collaborators of the Reactors and Processes Laboratory (Grenoble). The doctoral student will be involved in the different stages of the project, the publication of results and the presentation of their work at conferences. They will develop solid scientific knowledge in the fields of environment and energy, as well as in project management.