Banca de QUALIFICAÇÃO: ANA MELISSA PAULA BRITO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ANA MELISSA PAULA BRITO
DATE: 31/03/2023
TIME: 09:00
LOCAL: Complexo de Pós-Graduação do Centro de Tecnologia (PGTEC) - Sala 402
TITLE:

Green synthesis and characterization of the photocatalytic properties of Bi₂WO₆:xPr³⁺ obtained by microwave-assisted hydrothermal.

 

KEY WORDS:

Bismuth tungstate; praseodymium; beetroot extract; green synthesis; microwave-assisted hidrothermal method; and photocatalysis.

PAGES: 65
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

Green synthesis has shown to be a promising for obtaining nanoparticles because they have potential to degrade organic pollutants generated by textile industries. Due to its interesting properties, bismuth tungstate (Bi₂WO₆) stands out as a photocatalyst for environmental remediation and by its different ways of obtaining, such as coprecipitation, sol-gel and sonochesmitry. In this work, Bi₂WO₆:xPr³⁺ (x = 0; 0,01 and 0,03 mol) nanoparticles, with addition of beetroot extract (BE), were synthesized by the microwave-assisted hydrothermal method at 150°C for 60 min. Thus, the samples were structurally characterized by the X ray diffraction (XRD) and their morphology was investigated by the field emission scanning electron microscopy (FESEM). Photocatalytic activity of the samples was quantified by the UV-visible (UV-Vis) spectroscopy technique through the degradation of methylene blue (MB) and crystal violet (CV) dyes by ultraviolet and solar irradiation. It was verified, through XRD patterns, that the samples have an ortorhombic crystalline structure and good cristallinity, without the presence of secondary phases, which indicates that the presence of the Pr³⁺ dopant and the addition of beetroot extract do not generate additional phases. In addition, the crystallite size ranged from 5.66 nm to 10.10 nm, a slight increase was noted when the Pr³⁺ dopant was inserted, but as the amout of BE increased, the crystallite size decreased. The FESEM micrographs showed that the obtained nanoparticles have a predominantly flower-like morphology. The bandgap energy of the Bi₂WO₆:xPr³⁺ ranged from 3.56 eV to 3.65 eV. Photocatalytic tests indicated that all the samples have potential for AzM and VC discoloration. Futhermore, it was observed that the active photocatalytic mechanism, in UV and solar irradiation, mainly consists of superoxides and holes. Therefore, Bi₂WO₆:xPr³⁺ nanoparticles, using green synthesis and sunlight, is a promising, efficient and economical alternative for the degradation of organic dyes.

 

 

 

COMMITTEE MEMBERS:
Presidente - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Interna - 1802888 - FABIANA VILLELA DA MOTTA
Externa à Instituição - LILIA BASILIO DE CALAND - UERN