Banca de QUALIFICAÇÃO: VINICIUS RAMIRES DE LIMA PINTO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : VINICIUS RAMIRES DE LIMA PINTO
DATA : 18/03/2022
HORA: 18:00
LOCAL: UERN, MOSSORÓ-RN
TÍTULO:

ELECTROANALYSIS OF LEAD IN RIVER WATER USING BIOCHAR MODIFIED CARBON PASTE ELECTRODE.

PALAVRAS-CHAVES:

Biochar, Pyrolysis, Electroanalysis, Electrode, Sludge, Lead.

PÁGINAS: 56
GRANDE ÁREA: Outra
ÁREA: Ciências Ambientais
RESUMO:

Contamination of water resources, especially by heavy metals, is a matter of concern in the scientific community. Therefore, it is important to develop simple, fast, sensitive methodologies that allow on-site and real-time analysis of such contaminants. Thus, in the literature, alternative detection methods have been highlighted, such as electroanalysis, especially those that make use of carbon paste electrodes modified with biochar (EPCMB). This material, a product of pyrolysis, can be obtained from a multitude of biomasses, including the sludge from the effluent treatment plant (ETE) of the cashew nut processing industry (IBCC). In this work, the objective was to develop an electrochemical sensor of carbon paste modified with biochar obtained from sludge pyrolysis, to obtain an electroanalytical methodology for detecting lead in river water by differential pulse redissolution voltammetry (VRAPD). Temperatures of 200, 350 and 550°C, with a residence time of 90 minutes were used in the pyrolysis. Sludge and biochar characterizations were performed by XRF, TGA/DTGA analysis and Fourier transform infrared (FTIR) spectroscopy. Three electrodes of carbon paste modified with biochar (EPCMB) obtained at different temperatures, and two more electrodes, one of carbon paste (EPC) and another modified with sludge (EPCML) were constructed for comparison purposes. The electrodes modified with biochar presented the most intense peak currents (Ip) for the same lead concentration, with the Ip of the electrode obtained at a temperature of 550°C (EPCMB550) being the most intense. This electrode was used in the construction of the calibration curve that presented a linear response in the range of 0.79x10^-6 mol L^-1 to 1.67x10^-6 mol L^-1, with R² = 0.9998 and detection and quantification limits of 0.2404x10^-6 mol L^-1 and 0.8012x10^-6 mol L^-1 respectively. The repeatability and reproducibility of the voltammetric response was also studied and the DPR obtained were 1.31% and 2.54% respectively. The electrochemical method was applied to the determination of lead in a real sample of river water; the recovery percentage value was 94.5%. Biochar allowed an increase in the sensitivity of the method and the results showed that the EPCMB550 can be used to detct lead in real samples in an accurate and reproducible way.

MEMBROS DA BANCA:
Externo ao Programa - 12768 - KEURISON FIGUEREDO MAGALHÃES
Interna - 2470 - SUELY SOUZA LEAL DE CASTRO
Interno - 007.972.984-36 - THIAGO MIELLE BRITO FERREIRA - UFCA