{"id":20080,"date":"2025-11-26T10:49:37","date_gmt":"2025-11-26T09:49:37","guid":{"rendered":"https:\/\/navier-lab.fr\/?post_type=event&p=20080"},"modified":"2025-11-26T10:49:37","modified_gmt":"2025-11-26T09:49:37","slug":"seminaire-rmp-dr-adilson-samba-rmp-navier","status":"publish","type":"event","link":"https:\/\/navier-lab.fr\/en\/agenda\/seminaire-rmp-dr-adilson-samba-rmp-navier\/","title":{"rendered":"S\u00e9minaire RMP: Dr. Adilson Samba (RMP, Navier)"},"content":{"rendered":"

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Osmotic Compression\u2013Driven Zeolite Formation: In Situ Monitoring of Gel-to-Crystal Transition by \u00b9H NMR Relaxometry.<\/h1>\n<\/div>\n<\/div><\/div><\/div><\/div><\/section>
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Abstract:<\/strong><\/h2>\n
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Zeolites are crystalline aluminosilicates with high porosity and tunable surface properties, widely used as catalysts, adsorbents, and ion exchangers. Their conventional hydrothermal synthesis, however, is energy-intensive and poorly suited for real-time monitoring of the gel-to-crystal transition. In this work, we introduce an alternative, low-energy approach for zeolite synthesis based on osmotic compression of aluminosilicate gels. By applying a controlled osmotic pressure gradient using polyethylene glycol (PEG) solutions across a semi-permeable membrane, water is extracted from the gel, inducing densification and subsequent crystallization at room temperature.<\/p>\n

To probe the kinetics of water transport and gel-to-crystal transformation, we developed a non-invasive in situ monitoring strategy using \u00b9H NMR relaxometry. A custom-designed, 3D-printed miniaturized osmotic cell compatible with NMR measurements enables the real-time acquisition of T\u2082 relaxation distributions. These distributions provide quantitative information on water populations (free vs. bound) and their evolution during osmotic stress.<\/p>\n

Our results reveal a clear correlation between gel shrinkage, T\u2082 decay, and zeolite formation, confirming that proton NMR relaxation is a sensitive probe of structural evolution during osmotic compression. In addition, the water transfer measured by 1H NMR was successfully predicted by a diffusion-type model based on the aluminosilicate particle volume fraction. This methodology establishes a novel, energy-efficient, and physically insightful route for zeolite synthesis and opens prospects for monitoring and controlling phase transitions in colloidal or gel-based materials under osmotic confinement.<\/p>\n<\/div>\n

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Bio:<\/strong><\/h2>\n
Adilson Francisco Lu\u00eds SAMBA, \u00e0 la suite de mes \u00e9tudes d\u2019ing\u00e9nieur en g\u00e9nie des proc\u00e9d\u00e9s et bioproc\u00e9d\u00e9s \u00e0 l\u2019Ecole Polytechnique de l\u2019universit\u00e9 de Nantes (2016-2019) avec une sp\u00e9cialisation sur la mod\u00e9lisation des ph\u00e9nom\u00e8nes de transferts et les outils num\u00e9riques appliqu\u00e9s au g\u00e9nie des proc\u00e9d\u00e9s, j\u2019ai poursuivi une th\u00e8se de doctorat en G\u00e9nie des proc\u00e9d\u00e9s et des produits \u00e0 l\u2019universit\u00e9 de lorraine (2021-2024), au laboratoire LRGP de Nancy (Laboratoire de R\u00e9actions et G\u00e9nie des Proc\u00e9d\u00e9s). Mes travaux de th\u00e8se portaient sur la caract\u00e9risation exp\u00e9rimentale et mod\u00e9lisation des fluides rh\u00e9ologiquement \u00e9volutifs, j\u2019ai d\u00e9velopp\u00e9 une approche globale permettant de simuler \u00e0 la fois une cin\u00e9tique rh\u00e9ochimique comme les r\u00e9actions de polym\u00e9risation ainsi que les cin\u00e9tiques rh\u00e9ophysiques comme la visco\u00e9lasticit\u00e9, la thixotropie, g\u00e9lification. Le but \u00e9tait de d\u00e9velopper un mod\u00e8le facilement impl\u00e9mentable dans les codes de calculs CFD comme Ansys Fluent, Comsol, etc., pour simuler l\u2019\u00e9coulement de ces fluides dans des situations industriels (proc\u00e9d\u00e9s d\u2019\u00e9mulsification, extrusion r\u00e9active, erc.).\u00a0 Actuellement, depuis Mars 2025, je travaille en tant qu\u2019ing\u00e9nieur post-doctorant au CEA Marcoule en collaboration avec le laboratoire Navier, dans le cadre du projet Amor\u00e7age. Il s\u2019agit de synth\u00e9tiser des nanomat\u00e9riaux (z\u00e9olites, MOFs) par compression osmotique monitor\u00e9s par la RMN 1<\/sup>H<\/span><\/div>\n

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