Banca de DEFESA: LUAN DO NASCIMENTO DE MOURA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUAN DO NASCIMENTO DE MOURA
DATE: 15/07/2026
TIME: 10:00
LOCAL: Video oncerencia
TITLE:

Development of Nanostructured Carbons via Zeolite Templating from LDPE Pyrolysis

KEY WORDS:

Zeolite Templated Carbon; LDPE; faujasite; pyrolysis; microporous carbon; DFT.

 

PAGES: 210
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

Zeolite Templated Carbons (ZTCs) constitute a class of microporous crystalline carbon materials of high scientific and technological interest due to their high specific surface area, structural organization derived from the zeolitic template, and potential applications in adsorption, catalysis, and energy storage. In this thesis, an alternative route for the synthesis of ZTCs was developed using low-density polyethylene (LDPE) as a solid carbon precursor and faujasite-type zeolites as templates. Initially, FAU and FSY zeolites were synthesized and characterized by the hydrothermal route, evaluating parameters such as gel composition, sodium content, crystallization time, use of crystalline seeds, and TBAOH amount. FAU exhibited a crystalline structure compatible with zeolite Y, whereas FSY was also obtained with a higher SiO₂/Al₂O₃ ratio, although its formation critically depended on increasing the amount of organic structure-directing agent. Subsequently, LDPE pyrolysis was investigated as a source of carbonaceous species capable of diffusing through the zeolitic bed and forming confined carbon. Fractionated feeding of the polymer after thermal stabilization of the template proved essential to increase the efficiency of carbon deposition. The best results were obtained using the commercial zeolite CBV-500, especially at 700 °C, corresponding to sample ZTC-RUN16, which exhibited an SPD of 0.36, a BET specific surface area of 2875 m² g⁻¹, and a pore volume of 1.15 cm³ g⁻¹. In contrast, the synthesized FAU and FSY zeolites showed low carbon deposition, indicating that the presence of the faujasitic structure alone is not sufficient to ensure efficient ZTC formation. XRD, N₂ physisorption, and Raman analyses indicated the formation of microporous, aromatic carbon with a relative degree of structural disorder, characteristic of type-II ZTCs. Additionally, ab initio molecular dynamics and DFT simulations demonstrated that adsorption and reactivity are distinct phenomena, with ethylene activation depending on the location of cationic and protonic sites in the faujasite structure. The results indicate that the efficient formation of ZTC from LDPE depends on the combination of polymer thermal decomposition, microporous accessibility, acidity, active-site distribution, and pyrolysis conditions.

COMMITTEE MEMBERS:
Presidente - 1308577 - SIBELE BERENICE CASTELLA PERGHER
Interno - 1350249 - RUBENS MARIBONDO DO NASCIMENTO
Externo à Instituição - RICARDO FACCIO
Externo à Instituição - Alexander Kurt Josef Sachse
Externa à Instituição - LINDIANE BIESEKI - UFRN