Banca de DEFESA: Matheus Almeida Ferreira

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Matheus Almeida Ferreira
DATE: 14/10/2022
TIME: 14:00
LOCAL: Sala de Informática do PTARH com Transmissão pela Plataforma MS Teams
TITLE:

Degradation of cylindrospermopsin by Fenton Process: Kinetics and Effects of pH, Cylindrospermopsin concentration and doses of H₂O₂ and Fe(II).

KEY WORDS:

Keyords: cylindrospermopsin removal; advanced oxidation processes; Fenton process.

PAGES: 139
BIG AREA: Engenharias
AREA: Engenharia Sanitária
SUMMARY:

ABSTRACT 

The cyanotoxin cylindrospermopsin (CYN) has become a significant environmental and human health concern as this cyanotoxin has a high toxicological potential and CYN-producing cyanobacteria are found in water bodies all over the globe. High concentrations of cyanotoxins may be produced during cyanobacterial blooms, and special attention is required when these blooms occur in sources of water intended for human consumption because extracellular cyanotoxins are not effectively removed by conventional drinking water treatments. Thus, advanced treatment technologies such as Fenton’s oxidation process are needed to produce safe water. In this context, the present study aimed to evaluate, on a bench scale, the application of the Fenton process for CYN degradation in three different water matrices: ultrapure water (UW), ultrapure water in the presence of methanol (UWM) and Paranoá Lake water in the presence of methanol (PLWM). For all matrices, the optimal H₂O₂/Fe(II) molar ratio for CYN degradation was 0.4, with maximum degradation efficiency of 91% for UWM (50 µM H₂O₂ and 125 µM Fe(II)) and 98% for PLWM (100 µM H₂O₂ and 250 µM Fe(II)). Regarding the initial CYN concentration, based on experiments conducted in UWM and with 25 µM H₂O₂ and 62.5 µM Fe(II), it was observed that the degradation efficiency decreased from 99 to 86% when the CYN concentration increased from 0.05 to 0.2 µM. Similar behavior was observed in experiments conducted in PLWM and with 75 µM H₂O₂ and 187.5 µM Fe(II), in which the degradation efficiency decreased from 94 to 85% when the concentration of CYN increased from 0.05 to 0.2 µM. Furthermore, CYN degradation by Fenton process was shown to be poorly dependent on the presence of other organic compounds in the matrix, since the addition of 5 mg/L of humic acids, 125 µM C of algogenic organic matter and 513.3 µM of methanol resulted in a maximum efficiency loss of 16% for the optimal H₂O₂/Fe(II) molar ratio of 0.4. Regardless of the matrix analyzed, degradations of CYN higher than 93% were obtained for pH values between 3 and 5. Under the conditions herein analyzed, CYN degradation by Fenton process followed the pseudo-first-order (0.910 × 10^-3 s^-1) kinetic model for UWM and pseudo-second-order (1.314 × 10⁵ M^-2 s^-1) and pseudo-third-order (1.878 × 10¹³ M^-2 s^-1) kinetic model for PLWM. 

BANKING MEMBERS:
Externo à Instituição - JOSÉ ROBERTO GUIMARÃES - UNICAMP
Presidente - 1122604 - CRISTINA CELIA SILVEIRA BRANDAO
Interna - 1646057 - YOVANKA PEREZ GINORIS