Banca de DEFESA: SÁRA RAYSA SILVA PEÇANHA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : SÁRA RAYSA SILVA PEÇANHA
DATE: 27/02/2023
TIME: 15:00
LOCAL: Departamento de Química
TITLE:

NiAl MIXED OXIDES COMPOSITES AND SILVER NANOPARTICLES FOR METHYLENE BLUE PHOTODEGRADATION

KEY WORDS:

Photocatalysis, mixed oxide, composite, plasmonic resonance

PAGES: 80
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Foto-Química Inorgânica
SUMMARY:

In this study, the photocatalysis of methylene blue in the presence of mixed oxide based on Ni and Al associated with silver nanoparticles was evaluated. It is suggested that the presence of metallic nanoparticles amplifies photocatalytic effects by plasmonic effects and this hypothesis led to the development of this material. The oxide was synthesized by the coprecipitation method at controlled pH, obtaining lamellar structures based on Ni and Al terephthalate, followed by obtaining the material in the form of mixed oxide by calcination. In the process, attempts were made to obtain the inclusion of Ti in the oxide, but without success. The composite in powder form was obtained from the association of mixed oxide with AgNPs previously prepared by colloidal route. The materials were characterized by X-ray diffraction, infrared spectroscopy, Zeta potential, transmission electron microscopy and scanning electron microscopy with elemental analysis. The results indicated the formation of a mixed oxide of Ni and Al with nanostructured morphology and agglomerated in the form of fine flakes. The Ag nanoparticles used are thin, with rounded morphologies, zeta potential ζ = -42.1 mV and average dimension d = 14±8 nm. The composites showed amplified photodegradation after association with AgNPs, with about 85% and 78% for UV and visible systems, respectively, while for pure NiAl oxide, degradation of 75% and 65% was observed. These results reinforce that photocatalysis assisted by Ag nanoparticles is a combination that makes the system more efficient in the degradation of persistent organic pollutants such as dyes. Furthermore, it is suggested that the negative charge on the surface of the composites favors the association of cationic dyes, making the heterogeneous photocatalysis process more efficient for this class of compounds.

COMMITTEE MEMBERS:
Externa ao Programa - 1299792 - ANA CLAUDIA VAZ DE ARAUJO - nullPresidente - ***.823.784-** - BEATE SAEGESSER SANTOS - UFPE
Interna - ***.999.014-** - JULIANA ANGEIRAS BATISTA DA SILVA - UFPE