Banca de QUALIFICAÇÃO: MAITÊ MEDEIROS DE SANTANA E SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : MAITÊ MEDEIROS DE SANTANA E SILVA
DATA : 08/08/2016
HORA: 14:00
LOCAL: SALA DO CATRE
TÍTULO:

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

PALAVRAS-CHAVES:

Molybdate strontium, complexation reaction, characterization, experimental design, photobleaching.

PÁGINAS: 96
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Química
RESUMO:

In this work, the strontium molybdate (SrMoO4) processed by a complexation reaction of complexing agents (EDTA and citric acid) and metal ions present in solution to investigated the influence of pH (6, 7,5 and 9), time calcination (3, 4 and 5h) and heating rate (5, 7 and 10°Cmin-1). The materials were characterized by TG / DSC, XRD, EDX, SEM and DRS analysis. Based on the analysis performed, the experimental results showed that the decomposition of all volatiles in TG curve for SrMO4 it occurred until the temperature of 600°C. All the XRD patterns were indexed according to JCPDS 01-085-0586 record with tetragonal structure of scheelite type and space group I41/a, no secondary phases were identified. The lattice parameters were obtained from the  Reitveld refinement method , and reliability of results is a function of the residual parameter (S) when it’s close to an  unity. The EDX analysis (atomic%) showed small variations in the composition of Sr and Mo. The SEM data generally indicate the pictures powders are composed of large agglomerates of particles consisting of crystallites of different sizes with irregular spheres morphology when small and intermediate and large size with bipyramidal morphology. DRS in the ultraviolet and visible regions indicated the presence of intermediate energy levels within the bandgap, demonstrating that the samples calcined with a heating rate equal to 10°C/min are lower bandgap values (4.18 and 4.17 eV to pH 6 and 9, respectively) analyzed by an experimental design 2³. Thus, the synthesis route proposal was presented as a good alternative for the production of these oxides, providing materials with pure phase, high crystallinity and stoichiometric relationship very close to the theoretical. The bandgap estimates indicate that pH-independent material calcined with heating rate 10 ° C / min was present as a material which will promote better transition of electrons in the valence band and conduction band. Exploratory testing for degradation of methylene blue indicates that the produced powder has influences the photobleaching process of this contaminant.

MEMBROS DA BANCA:
Externo ao Programa - 2929066 - ANDRE LUIS LOPES MORIYAMA
Externo à Instituição - ANGÉLICA BELCHIOR VITAL - UFRN
Presidente - 349801 - CARLSON PEREIRA DE SOUZA
Externo ao Programa - 338292 - JOÃO BOSCO LUCENA DE OLIVEIRA