Banca de QUALIFICAÇÃO: JORGE LEANDRO AQUINO DE QUEIROZ

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JORGE LEANDRO AQUINO DE QUEIROZ
DATE: 27/09/2021
TIME: 09:00
LOCAL: VIDEOCONFERÊNCIA
TITLE:

Miniaturized electrochemical sensors: Development, characterization and application to monitoring reactors for wastewater treatment

 

KEY WORDS:

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

PAGES: 85
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 array was obtained from discarded computer microchips. The array 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 = 0.993) on the concentration range from 1.57 to 91.80 μmol L-1. Currently, we are applying this modified sensor to real time monitoring the antibiotic during its degradation by EAOPs.

BANKING MEMBERS:
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Externa à Instituição - DANYELLE MEDEIROS DE ARAUJO - UERN
Interno - 348475 - DJALMA RIBEIRO DA SILVA
Externa à Instituição - SUELY SOUZA LEAL DE CASTRO - UERN