Banca de DEFESA: JOSÉ EUDES LIMA SANTOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JOSÉ EUDES LIMA SANTOS
DATE: 19/01/2021
TIME: 09:00
LOCAL: VIDEO CONFERENCIA
TITLE:

STUDY OF THE EFFICIENCY OF CATHODIC PRODUCTION OF H₂ FROM THE ADVANCED ELECTROCHEMICAL OXIDATION OF RED METHYL AND SODIUM 2,4-DICLOROPHENOXYACETATE POLLUTANTS

KEY WORDS:

: Methyl Red. 2,4-DNa. Non active anodes. Hydrogen production. Electroxidation.

PAGES: 111
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Eletroquímica
SUMMARY:

Environmental pollution, especially of water, and the energy crisis caused by the growing use of fossil fuels are two of the greatest contemporary world problems that require an immediate solution. For this reason, this work proposed to evaluate the efficiency of hydrogen production from the oxidation of two of the most polluting sources of water, dyes and herbicides. For this purpose, the electrochemical oxidation of the methyl red dye (MR) and the herbicide 2,4-dichlorophenoxyacetate (2,4-DNa) was investigated in the anodes of Si/BDD, Pb/PbO₂ and Ti/Sb doped SnO₂ in acidic aqueous medium by applying 30 mA cm^-2 with simultaneous production and quantification of the hydrogen gas produced in the cathode bay. The electrochemical experiments were performed in an electrochemical cell of two compartments separated by a Nafion® membrane. The electrochemical degradation process was monitored by UV-VIS spectroscopy, HPLC and Total Organic Carbon analysis. The electrocatalytic properties of anodes and cathodes were evaluated by Tafel parameters obtained by linear sweep voltammetry. The results clearly showed that MR and 2,4-DNa can be oxidized over such anodes, but both the oxidation level and anodic current efficiency varied significantly between these materials. Si/BDD had the highest electrochemical removal capacity of organic pollutants, which was attributed to the high participation of hydroxyl and sulphate radicals. The formation of the sulfate radical, only in the anode of BDD, inhibited the production of oxygen in the anode by about 50% in 0.5 mol L^-1 of H₂SO₄. Regarding hydrogen production, the results showed that the H₂ production rate is dependent on the current applied, the electrolysis time and the cell design. Moreover, the cathodic current efficiency was higher than 80% in the type H cell and 100% in the type II cell. The use of alternative cathodic materials to platinum has efficiencies similar to this noble metal, differing only in its chemical/electrochemical stability in the electrolytic medium studied and in the overpotential of hydrogen. With hydrogen production, the energy consumption of the electrochemical system can be reduced by up to 44% with the BDD anode supported on niobium and platinum cathode on 2 mol L^-1 of H₂SO₄. Therefore, with this coupled system it is possible to reduce the impact of water pollution and generate a clean energy source that can be used to reduce the cost of electrochemical water treatment processes.

BANKING MEMBERS:
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Externa à Instituição - DAYANNE CHIANCA DE MOURA - UFRN
Externo à Instituição - MARCO ANTONIO QUIROZ ALFARO - udlap
Externa ao Programa - 1412709 - NEDJA SUELY FERNANDES
Interna - 2413537 - POLLYANA SOUZA CASTRO
Externa à Instituição - SUELY SOUZA LEAL DE CASTRO - UERN