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.