Banca de QUALIFICAÇÃO: THAISE DE VASCONCELOS NASCIMENTO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : THAISE DE VASCONCELOS NASCIMENTO
DATE: 03/01/2020
TIME: 10:00
LOCAL: Auditório do NUPPRAR
TITLE:

Decontamination of effluents generated in analytical chemistry laboratory classes through electrochemical processes

KEY WORDS:

Electrocoagulation, Eryochrome black T, Lead, Electrochemical oxidation

PAGES: 95
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Eletroquímica
SUMMARY:

The present work has as objective the treatment of effluents generated in the teaching laboratories. Thus, the work was divided in two parts: first, a study of the removal of Eriochrome Black using the electrocoagulation and electrochemical oxidation process was carried out. different operating conditions such as current density, sacrificial anode materials, active electrode area, mass transport analysis (flow and batch). The effluent used in this work was obtained from the water hardness determination test by complexation titration, according to the practical classes script of the Quantitative Analytical Chemistry course, offered by the UFRN Chemistry Institute. The best operating conditions achieved for both systems were: For batch system with current density of 15 mA.cm-2, initial pH of 10, Fe anode and Al cathode, with active electrode area of 40 cm2. , electrolysis time 120 min. For the flow system, the best conditions were achieved with 240 min of treatment, current density of 15 mA.cm-2, initial pH of 10, with active electrode area of 180 cm2. Then, for both batch and flow systems, the electrochemical oxidation treatment with current density of 15 mA.cm-2 was made using the boron-doped diamond anode (DDB), with an active area of 40 cm2. Considering the electrocoagulation alone, in the batch system 100% of discoloration was obtained in the first 15 min and after 120 min of operation a reduction in chemical oxygen demand (COD) of 84%. When coupled the electrochemical oxidation system was achieved around 98% in reducing COD, with total energy consumption of 7.95 kWh.m-3. For the flow system 70% color removal was obtained after 240 min and around 25% COD reduction considering only the electrocoagulation treatment. When coupled the oxidation treatment achieved 100% removal in discoloration and a 40% increase in COD reduction after 240 min, reaching an overall COD reduction of 65%, with a total energy consumption of 6%. , 97 kWh.m-3. In both systems, the results clearly show that the batch and flow system are alternatives for degrading dye-containing effluents, as they guarantee the legal limit values for the treated effluent to be disposed of. As a second work, the treatment for real effluent was done, based on the practical classes of the Analytical Chemistry Discipline, containing lead, using the same conditions for the best treatment with the dye (Fe anode and Al cathode, current density). 15 mA.cm-2, active electrode area of 40 cm2, electrolysis time of 120 min), obtaining 97% lead reduction in the sample, such analysis was determined using the differential pulse technique. ICP analysis was performed before and after treatment, yielding an 86% reduction in Pb2 + in the sample), showing that the electrochemical lead quantification technique is a fast, reliable, economical and simple technique for determining Pb2 +, also ensuring good sensitivity. The results of both studies demonstrate the potential of electrochemical techniques for the treatment of effluents generated in teaching laboratories, so that they can be disposed of in the aquatic ecosystem.

BANKING MEMBERS:
Externa ao Programa - 1530500 - ANA CRISTINA FACUNDO DE BRITO PONTES
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Externa à Instituição - DANYELLE MEDEIROS DE ARAUJO - UERN
Interno - 348475 - DJALMA RIBEIRO DA SILVA