Banca de DEFESA: JORGE LEANDRO AQUINO DE QUEIROZ

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JORGE LEANDRO AQUINO DE QUEIROZ
DATE: 28/01/2022
TIME: 14:00
LOCAL: Google meet
TITLE:

Development of miniaturized electrochemical sensors for monitoring species of environmental relevance.

KEY WORDS:

Miniaturized electrochemical sensors. Integrated Pt microelectrode. Au microelectrode set. Electrochemical advanced oxidation processes. Hydrogen peroxide. Isoniazid.

PAGES: 100
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Eletroanalítica
SUMMARY:

Electrochemical advanced oxidation processes (EAOPs) are new and promising methodologies for wastewater treatment, at domestic or industrial level, that emerge as an alternative to traditional water treatment methods. On EAOPs reactors, a wide variety of organic or inorganic pollutants can be degraded by strong oxidizing agents electrochemically generated. Therefore, on these processes, it is crucial a proper monitoring for the generation of oxidants and the degradation of pollutants in order to make the process more efficient and reduce costs. Thus, in this work we propose the utilization of miniaturized electrochemical sensors for the real time monitoring of species generated or degraded in the reactor. First, an integrated Pt microelectrode (a microelectrode that combines a working Pt microdisc to a silver quasi-reference electrode) for monitoring hydrogen peroxide generated in the reactor. Using this integrated microelectrode it was possible to obtain a real-time profile for H2O2 generation by the electrolysis of a 0.10 mol L-1 HClO4 solution. The reactor was equipped with a Nb/BDD anode and a Ti cathode under different current densities (30, 60, 90 e 120 mA cm-2). The H2O2 generation rate was strongly dependent on the applied current density (j) and that it reaches its peak production after 90 minutes of electrolysis, exhibiting a pseudo zero-order kinetics. The results obtained were in accordance with a spectrophotometric method used as reference at a 95% level of confidence. In a second approach, a gold microelectrode set was obtained from discarded computer microchips. The set of microelectrodes was modified with electrochemically reduced graphene oxide and applied to quantify isoniazid antibiotic by linear scan voltammetry, showing a good linear correlation (R2 = 0.9926) and limit of detection (1.38 μmol L-1) on the concentration range from 5.0 to 100.0 μmol L-1. The sensor was then applied to isoniazid determination in river and lagoon water samples.

BANKING MEMBERS:
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Interno - 348475 - DJALMA RIBEIRO DA SILVA
Interna - 2413537 - POLLYANA SOUZA CASTRO
Externo à Instituição - FABIANA DA SILVA FELIX
Externo à Instituição - MARCO ANTONIO QUIROZ ALFARO - udlap
Externa à Instituição - SUELY SOUZA LEAL DE CASTRO - UERN