Banca de DEFESA: MAITÊ MEDEIROS DE SANTANA E SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : MAITÊ MEDEIROS DE SANTANA E SILVA
DATA : 26/08/2016
HORA: 14:00
LOCAL: AUDITÓRIO DO PPGEQ
TÍTULO:

"Synthesis and characterization of Strontium molybdate obtained from the Complexation Method Combining EDTA / Citrate for photocatalytic degradation dye the textile industry."

PALAVRAS-CHAVES:

 strontium molybdate, complexation reaction, characterization of ceramic powders, experimental design, heterogeneous photocatalysis.

PÁGINAS: 106
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Química
RESUMO:

This work describes the production of strontium molybdate (SrMoO₄) through complexation combined method EDTA / Citrate. Was investigated the influence of pH (6, 7,5 and 9), calcination time (3, 4 and 5h) and heating rate (5, 7 and 10°C.min^-1) some chemical parameters and physical. For this, was applied a factorial design with 2³ triplicate at the midpoint. The synthesized materials were characterized by TG / DSC, XRD, EDX, and SEM diffuse reflectance spectroscopy. Based on thermogravimetric curve of SrMoO₄ powders were calcined at 650°C. All the XRD patterns were indexed according to JCPDS 01-085-0586 record with tetragonal structure and space group I41/a, secondary phases and impurities not being identified. It was found that there are differences between mean intensities of the diffraction peaks of x-rays. Using statistical tools, it was found that the rate of heating was the independent variable showed the greatest influence on this difference. The lattice parameters of the crystal structure were obtained from the Rietveld refinement method. The residual parameter refinement ranged from 1.035 to 1.292. The EDX analysis showed the presence of deviations between the theoretical and experimental composition for strontium and molybdenum components; the percentage deviation ranged from 0.027 to 3.67% depending on the conditions of synthesis. According to the SEM micrographs, the synthesized powders are composed of agglomerates of particles with irregular and spherical morphology bipiramidal. According to the analysis of the experimental design, having as dependent variable the optical bandgap values, the samples calcined with a heating rate of 10°C.min^-1and time of 3 hours of reaction have lower bandgap values (4.18 and 4.17 eV for pH 6 and 9, respectively) compared to the calcined material in other conditions of synthesis. Exploratory testing of photobleaching of methylene blue dye indicate that the tested powder has influence in the process. Statistical models generated have been shown to describe the observed phenomena.

MEMBROS DA BANCA:
Externo à Instituição - ANDARAIR GOMES DOS SANTOS - UFERSA
Externo ao Programa - 2929066 - ANDRE LUIS LOPES MORIYAMA
Externo ao Programa - 2245481 - ANGÉLICA BELCHIOR VITAL
Presidente - 349801 - CARLSON PEREIRA DE SOUZA