Banca de DEFESA: RAFAELA GABRIEL

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : RAFAELA GABRIEL
DATE: 31/03/2023
TIME: 13:30
LOCAL: Sala de aulas do PPGEQ
TITLE:

STUDY OF THE EFFECTS OF STIRRING AND MIXING IN THE SYNTHESIS PROCESS OF LAMELLAR DOUBLE HYDROXIDES (LDHs)

KEY WORDS:

lamellar double hydroxides, mechanical variables and optimization.

PAGES: 98
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

The stirring and mixing process comprises the determination of mechanical parameters and sizing of the reactors, such as: stirring speed, types of impellers, baffles, among others. Such characteristics are crucial in promoting mass and energy transfer to the system and are associated with tank configurations. Process variables are commonly studied to define design and scale-up criteria for complex mixtures, such as processes that crystallize. The synthesis by coprecipitation of lamellar double hydroxides (HDLs), clays belonging to the class of mineral nanoparticles, is governed by the steps of nucleation and crystal growth, directly associated with the efficiency of the mixing and dispersion process of the reagents. However, in the literature there is no specific study on these effects and what they imply for the formation of LDH. Due to the lack of this information, this work proposes the study of mechanical parameters (process variables) in a batch reactor, for the synthesis of LDH by the coprecipitation method at variable pH. The study was carried out by evaluating the influence of the following process variables: stirring speed (200, 600 and 1000 rpm), stirring time (2, 10 and 18 h) and presence or absence of baffles, in response to the planning the structural and morphological characteristics of LDH. The evaluation of parameters should serve as a basis for improving the characteristics of LDH such as crystallinity, porosity and phase purity. In this sense, efforts are directed towards improving synthesis processes and optimizing the production of LDH and ensuring robustness and safety in industrial applications. In general terms, mechanical variables had an influence on the structural characteristics of HDLs, with significant changes in viscosity, density, yield (23.15 - 34.61%), crystallinity and crystallite size (70.99 - 174.79 nm).

BANKING MEMBERS:
Externo(a) à Instituição - GABRIELA SILVEIRA DA ROSA - Unipampa
Interno(a) - 1121112 - JOAO INACIO SOLETTI
Externo(a) à Instituição - KLEBER JEAN LEITE DOS SANTOS
Interno(a) - 3731108 - LIVIA MARIA DE OLIVEIRA RIBEIRO
Presidente - 1797785 - LUCAS MEILI
Interno(a) - 3182573 - RODOLFO JUNQUEIRA BRANDAO