Soutenance de thèse : Maxime Debost

Abstract

11/18/2019 – 10:00  AM – CNRT 2nd Floor

Keywords: Chabazite, CO₂ adsorption, CO₂ In-situ PXRD, PEDT, Nanozeolites, OSDA-free.

The goal of this work is to prepare template-free small pore nanosized zeolites. The direct synthesis of nanosized CHA and RHO type zeolites without organic structure directing agents provided materials with a Si/Al ratio suitable for the separation of CO₂ from CH₄. The first part of this study concerns the development of a new synthetic route towards preparation of small pore nanozeolites from water clear precursor suspensions. The nanocrystals have a diameter of 30 – 200 nm and a Si/Al ratio of 1.4 to 2.6. The second part is dedicated on the crystallographic analysis of the RHO and CHA nanosized zeolites in hydrated and dehydrated forms. Precession electron diffraction tomography (PEDT) and in-situ powder XRD methods were used to characterize the structure of the newly synthesized materials with nanosized dimensions. The third part of the thesis includes the adsorption studies of CO₂ and CH₄ in the CHA and RHO nanosized zeolites. The high selectivity of the zeolite nanocrystals synthesized with different cations (Cs, Na, K) towards CO₂ in the presence of CH₄ is demonstrated.