Banca de DEFESA: JORGE LEANDRO AQUINO DE QUEIROZ
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : JORGE LEANDRO AQUINO DE QUEIROZ
DATA : 27/07/2016
HORA: 09:00
LOCAL: Auditório do NUPPRAR
TÍTULO:
STUDY OF THE ELECTROCHEMICAL OXIDATION OF CARBOXYLIC ACIDS USING BORON DOPED DIAMOND ELECTRODE AND OXIDANT SPECIES PARTICIPATION
PALAVRAS-CHAVES:
Electrochemical oxidation. Boron doped diamond. Oxidant species. Oxidation mechanisms. Carboxylic acids
PÁGINAS: 92
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Físico-Química
ESPECIALIDADE: Eletroquímica
RESUMO:
In this work, the electrochemical oxidation of three carboxylic acids was studied – formic acid (FA), acetic acid (AA) and oxalic acid (OA) with niobium supported boron doped diamond (BDD) anode. These acids are usually accumulated during or in the end of various advanced oxidation processes, since they are more persistant than the initial pollutants. BDD anode is considered one of the best electrocatalytic materials for these processes, since that it acts efficiently on the generation of strongly oxidant species, such as hydroxil radicals, hydrogen peroxide and persulfates. Silicon is the most used substrate for the deposition of the diamond layer, but it is a fragile material. Therefore, niobium is shown as a promising alternative due its chemical and mechanical stability. Synthetic solutions containing the three carboxylic acids were submitted to anodic oxidation experiments, having as investigated parameters the current density (30, 60, 90 e 120 mA cm-2) and the supporting electrolyte (perchloric and sulfuric acids), as well as the effects of the structural differences of these acids. The degradation of the organic compounds was analyzed by means of chemical oxygen demand (COD), total organic carbon (TOC) and HPLC, while the oxidant species were detected using techniques reported on literature. Efficiency parameters (TCE, MCE and energy consumption) were also obtained. Electroanalytical studies shown that both direct and indirect oxidation processes can occur for these acids. The current density was determining parameter on the removal efficiency because higher COD removals were obtained when higher current densities were applied (60,7% for AA; 79,8% for FA and 87,8% for OA by applying 120 mA cm-2). The supporting electrolyte also influenced on the removal efficiency because the process was more efficient with the utilization of H2SO4 due the participation of persulfates, which led to higher COD removals (34,5% for AA; 82,5% for FA and 93,5% for OA by applying 120 mA cm-2) . Finally, the efficiency parameters provided a general view about the systems efficiencies and allowed to establish comparisons between both processes.
MEMBROS DA BANCA:
Externo ao Programa - 2140818 - AMANDA DUARTE GONDIM
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Externo à Instituição - DAYANNE CHIANCA DE MOURA - UFRN
Interno - 348475 - DJALMA RIBEIRO DA SILVA
Externo à Instituição - FABIO GARCIA PENHA - IFRN