Banca de QUALIFICAÇÃO: ADRIANA PERPETUA FIGUEIREDO PAULISTA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ADRIANA PERPETUA FIGUEIREDO PAULISTA
DATE: 29/02/2024
TIME: 10:00
LOCAL: videoconferência
TITLE:

In situ synthesis of carbon nanotubes from the conversion of ethylbenzene under SrFe₁₂O₁₉/SiO₂ oxides: Application in the photodegradation of paracetamol

KEY WORDS:

carbon nanotube; strontium hexaferrite; ethylbenzene; CVD method; photocatalysis

PAGES: 60
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Cinética Química e Catálise
SUMMARY:

Nanotechnology has gained prominence in recent decades due to the variety of applications it allows.  strontium hexaferrites in silica were prepared by the Pechini method and used as a catalyst in the reaction with ethylbenzene to produce carbon filaments. According to XRD, RAMAN and XPS analysis, the presence of SrFe₁₂O₁₉, hematite and amorphous silica phases was confirmed. The SEM and TEM indicate the formation of material with a clurters morphology. Through SEM analysis after the CVD method, it was possible to observe the formation of carbon filaments that appeared during the catalytic reaction of ethylbenzene. TEM confirms this formation and indicates the formation of tubes with a diameter in the average range of 60 nm. The post-reaction XRD indicates the formation of the carbon, SrFe₁₂O₁₉, SiO₂ and Fe⁰ phases, showing a reduction in the hematite phase. The growth of the tubes occurs from metallic iron, considering that the tip of the tube contains only iron according to EDS results from TEM images. The RAMAN spectrum showed the D and G bands characteristic of carbon, where the ratio between ID/IG varied depending on the reaction temperature. The reaction with the best catalytic performance achieved an average of 99% conversion and was selective primarily for ethylene with an average of 93% selectivity at a temperature of 650°C. In this way, it was possible to propose a mechanism for the formation of carbon nanotubes from the catalytic conversion of ethylbenzene using the CVD method. Therefore, the nanotubes formed applied to iron phases were applied in the photodegradation of paracetamol.

COMMITTEE MEMBERS:
Interna - 349770 - DULCE MARIA DE ARAUJO MELO
Externo à Instituição - MAICON OLIVEIRA MIRANDA - IFPI
Externo ao Programa - 1674707 - MARCO ANTONIO MORALES TORRES - nullPresidente - 2087667 - TIAGO PINHEIRO BRAGA