Banca de QUALIFICAÇÃO: ÁMISON RICK LOPES DA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ÁMISON RICK LOPES DA SILVA
DATE: 26/11/2019
TIME: 15:30
LOCAL: Anfiteatro B do CCET
TITLE:

Application of density functional theory (DFT) and quantum theory of atoms and Molecules (QTAIM)in the understanding of anodic oxidation of pollutants promoted by boron-doped diamond (BDD) anode

KEY WORDS:

DFT, QTAIM, BDD, Anodic Oxidation

PAGES: 100
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Química Teórica
SUMMARY:

In environmental electrochemistry, there is a centralized focus on effluent decontamination, using catalytic techniques and materials that promote the oxidation / mineralization of organic materials present in the effluent. Electrochemistry applied in this context is a treatment that fits green chemistry, as it avoids the use of aggressive reagents in the environment. The chemical complexity surrounding the oxidation of polluting molecules is studied step by step in order to understand and improve processes at the molecular level. One step further, as contributions from computational studies, apply to these molecular systems, have a complete character, because a literature is still considered poor in this collaboration of the fields of environmental electrochemistry and theoretical chemistry. To contribute to this focus and improve the literature, two systems have been studied. The first work, which composes these, deals with the evaluation of the result of an electroanalytical technique: cyclic voltammetry. Applied to caffeine using boron-doped diamond anode (BDD). The electroanalytical profile displayed for this system results in an oxidative peak, which presents a coffee oxidation as a direct oxidation, ie, a peak that occurs before the water discharge potential. Indicating that caffeine oxidation occurs directly on the surface of the BDD. From the information provided by the experimental measurements, a BDD surface cluster was computationally used to verify coffee-electrode interactions, obtaining thermodynamic parameters and geometric interactions by DFT, QTAIM and ELF (Electronic Location Function) calculations. According to the results of the energy analysis, obtained from the DFT, as more and less stable geometries were used thermodynamically. Topological data of interaction geometries were used using QTAIM and ELF to verify how influences occurred during an interaction and relationship to the interaction energy. The second work, which includes, deals with a more active scenario, an anodic oxidation using BDD to mineralize another pollutant, the Eriochrome Black T (EBT) in solution with Mg²⁺ and Ca²⁺ cations. The oxidation made in batch, monitoring the decontamination by COD and UV-VIS. The behavior observed was opposite to the related literature, when the treatment used was electro-fenton. In this scenario, use of DFT to obtain the complex structures formed between EBT and cations, and after qtaim calculations applied the complexes in order to analyze the Metal-binder bonding in the complexes structure. The electronic density in these bonds reveals the strength of the complexes. In order to compare the facility order in undergoing oxidation among the complexes formed, considering complex with the tri and hexavalent coordination sphere.

BANKING MEMBERS:
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Interno - 1086214 - ANDERSON DOS REIS ALBUQUERQUE
Externo ao Programa - 338292 - JOAO BOSCO LUCENA DE OLIVEIRA