Banca de QUALIFICAÇÃO: ARYANDSON DA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ARYANDSON DA SILVA
DATE: 12/09/2025
TIME: 10:00
LOCAL: Videoconferência
TITLE:

Synthesis of advanced zeolitic materials for strategic gas capture.

KEY WORDS:

CO2 capture; storage; zeolites; cation exchange; CO2/CH4 selectivity; CO2/N2 selectivity

PAGES: 104
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Físico Química Inorgânica
SUMMARY:

Zeolitic materials are known for their unique characteristics, mainly due to the presence of pores with specific sizes (depending on the framework) and ordered structures that repeat throughout the material. These features enable applications ranging from cation exchange for hard water treatment, to catalysis in various reactions, and gas separation. Gas separation occurs due to the uniformity of the pores in the framework, allowing the separation of molecules with very similar sizes, such as CO2, N2, and CH4. Zeolitic materials can be modified to further enhance process efficiency through methods such as cation exchange, crystal size reduction, or even by changing process conditions, such as increasing temperature and pressure. Therefore, this work aims to study the synthesis and modification of three different zeolitic materials for the capture and storage of strategic gases for industry, namely CO2, CH4, and N2. For this purpose, LTA, RHO, and CHA zeolites were studied, undergoing cation exchange processes with alkali and alkaline earth metals, and applied in adsorption processes of CO2, CH4, and N2 at pressures ranging from 0.6 kPa to 10 kPa, and at temperatures of 273 K, 293 K, 308 K, and 323 K. Direct air capture (DAC) was also investigated, aiming to evaluate the performance of these materials under atmospheric conditions for CO2 capture. From the results, it was observed that for the LTA zeolite, the cation exchange that enhanced CO2 storage capacity was the exchange with calcium, which did not significantly alter the material’s characteristics but occupied less space inside the zeolite, thereby increasing the available internal volume. However, it also facilitated the entry of other gases, making it unsuitable for processes requiring high CO2 selectivity. For this purpose, the potassium-exchanged LTA zeolite showed the best performance, with higher CO2 selectivity compared to N2 and CH4. In the DAC study, the strontium-exchanged LTA zeolite stood out, showing stronger interactions with CO2 under these conditions. For the RHO zeolite, cation exchange with alkaline earth metals did not produce a functional structure, as these metals occupy less space and cause framework destabilization. In contrast, the alkali metals studied provided good results: the highest storage capacity was achieved with sodium-exchanged RHO. Regarding selectivity, results varied depending on the gas: lithium-exchanged RHO showed the best selectivity for N2, while potassium-exchanged RHO performed best for CH4. In DAC studies, RHO zeolite did not show promising results, with very low CO2 adsorption amounts, indicating that the material requires high CO2 concentrations to effectively store or selectively adsorb the gas. Comparing the three zeolites, CHA showed moderate results without major highlights. NaRHO presented the best storage performance, while potassium-exchanged LTA exhibited the highest CO2 selectivity.

COMMITTEE MEMBERS:
Externo à Instituição - ADONAY RODRIGUES LOIOLA - UFC
Interno - 350509 - ANTONIO SOUZA DE ARAUJO
Externo à Instituição - JHONNY VILLARROEL ROCHA - UNSL
Externa à Instituição - MARIELE IARA SOARES DE MELLO - UFRN
Presidente - 1308577 - SIBELE BERENICE CASTELLA PERGHER