Banca de DEFESA: GLEILSON DE FRANÇA VIEIRA
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : GLEILSON DE FRANÇA VIEIRA
DATE: 28/07/2023
TIME: 10:00
LOCAL: videoconferência
TITLE:
APPLICATION OF ELECTROCHEMICAL TECHNOLOGIES AS AN ALTERNATIVE FOR THE TREATMENT OF BEAUTY SALON EFFLUENTS
KEY WORDS:
Anodic Oxidation; Effluent; Beauty salon; Boron Doped Diamond
PAGES: 93
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Análise de Traços e Química Ambiental
SUMMARY:
One of the advanced oxidation electrochemical processes, also known as: anodic oxidation, is quite efficient in treating wastewater that contains different organic contaminants. In this scientific project, the effluent was collected during a normal day in a beauty salon located in the city of Natal, Brazil. This beauty salon effluent was treated using electrochemical oxidation without any previous treatment and its initial physical-chemical analysis showed a chemical oxygen demand (COD) of 1612 mg O2 L–1, turbidity of 477 NTU and the presence of trace-level metals such as iron, copper, chromium, and zinc (0.1; 0.03; 0.02; 0.02 L–1, respectively). The experimental analyzes were carried out in a laboratory-scale plant, using an electrochemical flow cell consisting of a circular stainless steel plate as cathode and another containing boron-doped diamond (BDD) as anode, both with an active surface of 69.4 cm2, separated by a distance of 1.7 cm. For each experiment, 1.2 liters of contaminated effluent was placed in the reservoir tank which was recirculated through the reaction compartment cell. Electrolyses were performed applying 10 and 30 mA cm–2, using different electrolytes (NaCl or Na2SO4) and concentrations (0.08 and 0.16 M). The experiments were conducted for 360 minutes and samples were collected at specific time intervals. Comparing the supporting electrolytes, NaCl performed better at a high concentration (0.16 mol/L). BDD electrodes are known to be efficient in promoting persulfate and sulfate radical generation from SO4–2 in the bulk solution, as well as reactive species based on the oxidation of Cl- ions. However, the formation of chlorinated species when NaCl is present in higher concentrations, combined with the generation of hydroxyl radicals on the anode surface, seems to be the main degradation route in this study. Furthermore, the low current density ensures better charging efficiency compared to the higher j, as the low j promotes better and efficient oxidation with less parasitic reactions. The addition of electrolytes is mandatory in order to obtain a better efficiency in energy consumption. Without salt to improve the conductivity of the solution, more than 100 kWh m–3 are consumed, while with the sulphate/chloride-based electrolyte this value decreases to approximately 20 kWh m–3. Under the best conditions (0.16 M NaCl, 10 mA cm–2), metals are eliminated from the effluent, and turbidity and COD decrease to 92 and 72%, respectively. The results prove that a simple treatment before release can lead to a less refractory effluent in the public sewage system.
COMMITTEE MEMBERS:
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Interna - 2140818 - AMANDA DUARTE GONDIM
Externa à Instituição - DANYELLE MEDEIROS DE ARAUJO - UNESP
Externo à Instituição - INALMAR DANTAS BARBOSA SEGUNDO - UFRN
Externo à Instituição - JOÃO MILLER DE MELO HENRIQUE - IFSERTAO