Banca de QUALIFICAÇÃO: ANALLYNE NAYARA CARVALHO OLIVEIRA CAMBRUSSI

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE: ANALLYNE NAYARA CARVALHO OLIVEIRA CAMBRUSSI
DATA: 21/09/2018
HORA: 09:00
LOCAL: Auditório do PPG em Ciência e Engenharia de Materiais
TÍTULO: SYNTHESIS OF CATALYST PALYGORSKITA-TIO2 AND SILVER NANOPARTICLES FOR THE DEVELOPMENT OF ASSAYS ANTIOXIDANT BASED ON THE GENERATION OF REACTIVE OXYGEN SPECIES
PALAVRAS-CHAVES: palygorskite; silver nanoparticles; TiO2; ROS; antioxidant activity.
PÁGINAS: 35
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Inorgânica
ESPECIALIDADE: Foto-Química Inorgânica
RESUMO:

The method based on photogeneration of reactive oxygen species in water from catalyst composed of palygorskite-TiO₂ and silver nanoparticles (AgNPs/TiO₂-PAL) was developed and applied to antioxidant assays. Silver nanoparticles were synthesized using silver nitrate solution, sodium borohydride reducing agent and Caraia gum as stabilizing agent. Incorporation of AgNPs into the previously synthesized TiO₂-PAL was performed. The catalyst AgNPs/TiO₂-PAL were characterized by UV-vis spectroscopy, X-ray diffractometry (XRD), Scanning Electron Microscopy (SEM), Zeta potential and Dynamic Light Scattering (DLS). The catalyst AgNPs/TiO₂-PAL were used to perform an antioxidant activity method which consisted in monitoring the dye discoloration , acid yellow 73 (AY73) in the presence of gallic acid antioxidant in different concentrations (10 to 100 μg.mL^-1) comparing to the dye discoloration in the absence of the antioxidant. A microplate reader (Elisa Polaris) was used to measure the discoloration of the aqueous solutions of AY73 dye, irradiated by UV light for 60 minutes. The effect of reactive oxygen species (ROS) generated by AgNPs/TiO₂-PAL based in photocatalytic kinetics of AY73 dye was investigated. The oxidation of AY73 dye by photocatalysis in the system with AgNPs/TiO₂-PAL catalysts was carried out mainly by the participation of O₂^•-, HO• and ¹O₂ species, in this order of importance. The results showed that the synthesis of the AgNPs/TiO₂-PAL catalyst was successfully carried out and the application of this material in the development of an innovative methodology for the determination of antioxidant activity was extremely promising.

MEMBROS DA BANCA:
Presidente - 2296591 - ALESSANDRA BRAGA RIBEIRO
Interno - 2199134 - MARCILIA PINHEIRO DA COSTA
Externo à Instituição - MARIANA DE MORAIS SOUSA - IFPI