Banca de DEFESA: LETÍCIA GRACYELLE ALEXANDRE COSTA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LETÍCIA GRACYELLE ALEXANDRE COSTA
DATE: 27/07/2023
TIME: 09:00
LOCAL: Auditório do NUPPRAR
TITLE:

Application of Electrochemical Oxidation for the generation of strong oxidants, generation of value-added products, and degradation of Paracetamol, Caffeine, and Olanzapine in synthetic effluents

KEY WORDS:

Electrochemical Oxidation; Pharmaceuticals; Oxidant Species; Carboxylic Acids Electrogeneration

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

Electrochemical wastewater treatments are facing a paradigm shift, instead of achieving complete mineralization of organic pollutants researchers are seeking to give economic value to the products generated during the degradation process. One of the products that are generated in the electrochemical oxidation process are volatile fatty acids. These acids are commodities used in various industrial segments such as the food, textile, and pharmaceutical industries. For this reason, this work proposed to evaluate the efficiency of electrochemical oxidation for the degradation of pharmaceutical compounds, trying to find the best conditions both for the removal of organic pollutants and for the electrogeneration of volatile fatty acids. The results achieved are divided into two chapters. The first chapter presents the evaluation of the oxidizing power of the electrogenerated Persulfate and Peroxophosphate solutions for ex situ application. It was observed that the increase in current density is proportional to the increase in oxidant concentration. In the ex situ oxidation process, a reduction of 46.66% for Persulfate and 47.15% for Peroxophosphate was achieved in the degradation of Paracetamol at a concentration of 20 mg L-1. The best condition for this type of application was when the lowest v/v volume ratio of oxidant was used (v/v = 0.5).  The second chapter presents the results found in the electrochemical oxidation of pharmaceutical compounds. The experiments were performed in a cell using a Boron Doped Diamond (DDB) anode, using 0.5M sulfuric acid and sodium sulfate as supporting electrolyte. The drugs paracetamol, caffeine and olanzapine were used as organic contaminants. The electrochemical degradation and acid formation process was monitored by High Performance Liquid Chromatography. It was possible to observe that in sulfuric acid medium the degradation of the compounds was achieved faster. Experiments with perchloric acid were carried out under the same condition to evaluate the influence of the sulfate radical on the degradation. By comparing the experiments, it was proven that the sulfate radical is mainly responsible for the process. The results of Total Organic Carbon showed that although there was complete degradation of the initial pollutant the organic matter present in the effluent was not completely consumed, indicating that there was the production of new organic products. Through chromatographic analysis, it was verified the emergence of acetic acid, formic acid and oxalic acid in the experiments with sulfuric acid as electrolyte. As for the experiments with sodium sulfate, acetic, formic, tartaric, and salicylic acids were observed.  Toxicity experiments with lettuce seeds were performed to see the possibility of reusing the effluent after treatment for agriculture. Only the seeds that were watered with the sodium sulfate treated effluent germinated. It is concluded that electrochemical oxidation is an efficient process for both the generation of oxidant species for in situ and ex situ applications, and for the electrogeneration of carboxylic acids.

COMMITTEE MEMBERS:
Interna - 2140818 - AMANDA DUARTE GONDIM
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Externa à Instituição - DANYELLE MEDEIROS DE ARAUJO - UNESP
Externo à Instituição - JOSÉ EUDES LIMA SANTOS - UNESP
Externo à Instituição - JOÃO MILLER DE MELO HENRIQUE - IFSERTAO