Banca de QUALIFICAÇÃO: PAULO ROBERTO RIBEIRO SOARES JÚNIOR

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : PAULO ROBERTO RIBEIRO SOARES JÚNIOR
DATE: 31/03/2023
TIME: 09:00
LOCAL: https://conferenciaweb.rnp.br/events/qualificacao-de-doutorado-paulo-roberto-ribeiro-soares-junior
TITLE:

Functional geopolymer based on metakaolin modified with a hybrid system of photocatalysts and graphene applied to the depollution of effluents

KEY WORDS:

Geopolymer; Photocatalysis; Reaction kinetics; Microstructure; Mechanical behavior; Pore structure; Self-cleaning potential.

PAGES: 70
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Construção Civil
SPECIALTY: Materiais e Componentes de Construção
SUMMARY:

Extreme events, such as high temperatures and floods, are nature's response to human actions. Planet Earth urges balance in the environmental, social, and economic scope. Since the cement is the most consumed material in the world, sustainable development necessarily involves eco-efficient practices in the construction sector. Geopolymers (Geo) are a class of alternative binders without clinker, almost always produced from waste. These features save resources (raw materials and energy) and reduce pollutant emissions. In parallel, there is an urgent demand for basic infrastructure, sanitation, and mitigation of environmental impacts. Advanced oxidative processes (AOP) have been successfully applied in environmental remediation, mainly in wastewater depollution. These two fields can be combined (Geo + AOP), generating functional building materials with optimized properties and self-cleaning potential. Despite being extremely relevant, studies in this area are still incipient, and the Geo + AOP association can be further investigated, especially regarding the influence of semiconductor oxides on the geopolymer matrix. In this sense, the present work will investigate the performance of a metakaolin-based geopolymer modified with a hybrid system of TiO₂/Fe₂O₃ photocatalysts (Geo-X). The influence of graphene addition will also be evaluated. Initially, metakaolin-based geopolymers will be produced from dosages with Si/Al, Na/Al, Na/Si, and w/b ratios that enable their use in engineering. Photocatalyst oxides will replace the precursor in percentages of 1%, 2%, 4% and 8%, and alternative sodium silicate and sodium hydroxide will be used as activators. Five approaches will be taken to investigate Geo-X comprehensively. Reaction kinetics and microstructure will be evaluated. The mechanical behavior at macro/micro/nano scales will be studied, and correlations between the levels of analysis will be proposed. The porous structure and water absorption will be examined. The self-cleaning potential is the focus of the work, in which the removal of organic dye in an aqueous medium, the remaining solution, and the surface affinity with water will be evaluated. The effect of graphene addition on electron mobility will be investigated. The main expected result concerns the identification of causes and mechanisms intrinsic to each of the observed phenomena/behaviors. In addition, the unpublished findings provided in the literature will contribute to expanding the knowledge frontier. Therefore, the impacts of this work go beyond the environmental scope, giving a close link with the sustainable development goals proposed by the United Nations, since the application of geopolymers in effluent depollution can improve the quality of water resources and promote better living conditions for people.

COMMITTEE MEMBERS:
Presidente - AUGUSTO CESAR DA SILVA BEZERRA
Interno - PETER LUDVIG
Externo à Instituição - ERICH DAVID RODRIGUEZ MARTINEZ - UFSM
Externo à Instituição - MURILO DANIEL DE MELLO INNOCENTINI - URP