| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 4.2 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
Atualmente, muitas substâncias são uma ameaça e ecológica e para a saúde
humana. Entre estes poluentes há uma preocupação relativamente aos PFAS devido à sua
persistência e bioacumulação. Os PFAS, são utilizados em muitos produtos de consumo
e têm sido encontrados em ecossistemas aquáticos. Uma vez que estes ecossistemas são
um habitat para uma variedade de criaturas e um abastecimento de água potável para o
Homem, isto representa um problema ecológico substancial.
Este estudo teve como objetivo desenvolver uma tecnologia de remediação híbrida
para a remoção de PFAS de matrizes aquáticas utilizando nanofotocatálise e
biorremediação. Foram testadas várias estirpes quanto à sua capacidade de degradar
compostos fluorados, a fim de criar um consórcio com um potencial para degradar os
PFAS resultantes do tratamento por nanofotocatálise. A estirpe COL5 apresentou uma
defluorinação completa do fluoroacetato de sódio, tal como a estirpe F11, mas para o
composto fluorobenzeno, ambos a uma concentração de 50 mgL-1
. A estirpe 3EE foi
capaz de defluorinar 17% do composto epoxiconazole a 5 mgL-1
e a estirpe DPS8
desflorou 20% da paroxetina a 1 mgL-1
. Tentou-se avaliar a biocompatibilidade entre as
estirpes que apresentaram os melhores desempenhos de defluorinação, mas, devido à
contaminação, não foi possível concluir. A nanofotocatálise foi realizada com
nanopartículas de TiO2 e ZnO a uma concentração de 1 gL-1
. Esses ensaios foram
realizados em uma solução de água desionizada contendo ácido perfluorohexanóico e
noutra solução com trifloxistrobina, ambas na concentração de 1 mgL-1
. Verificou-se, por
potenciometria, que o tratamento com nanopartículas de ZnO levou à defluorinação de
27% da trifloxistrobina em 6 horas. Por outro lado, o tratamento do ácido
perfluorohexanóico e da trifloxistrobina (1 mgL-1
) pelo consórcio sintético não resultou
em biodegradação. Finalmente, quando a tecnologia foi testada em conjunto, o consórcio
sintético foi capaz de defluorinar uma pequena percentagem de trifloxistrobina (4,7%).
Em conclusão, embora tenham sido encontradas estirpes capazes de degradar
compostos fluorados, não foram capazes de defluorinar PFAS quando incluídos num
consórcio sintético. A nanofotocatálise por nanopartículas de ZnO, por outro lado,
mostrou um potencial de degradação da trifloxistrobina. Ao juntar estas duas tecnologias,
obteve-se uma percentagem de defluorinação de cerca de 30%.
Today, many substances pose a serious threat to human and ecological health. Due to their persistence, bioaccumulation, and possible negative consequences, PFAS have emerged as particularly worrying among these pollutants. PFAS, have been widely found in aquatic ecosystems. Since these ecosystems are an essential habitat for a wide variety of creatures and a crucial supply of drinking water for human societies, this poses a substantial ecological problem. This study aimed to develop a hybrid remediation technology for the removal of PFAS from aquatic matrices using nanophotocatalysis and bioremediation. Several strains were tested for their capabilities of degrading fluorinated compounds to create a consortium with potential do degrade PFAS resultant from the nanophotocatalysis treatment. Strain COL5 showed complete defluorination of sodium fluoroacetate, as did strain F11 but for the compound fluorobenzene, both at a concentration of 50 mgL-1 . Strain 3EE was able to defluorinate 17% of the compound epoxiconazole at 5 mgL-1 , and strain DPS8 defluorinated 20% of paroxetine at 1 mgL-1 . Biocompatibility between the strains showing the best defluorination performances was studied, but due to contamination, it was not possible to verify compatibility between them. The nanophotocatalysis experiments were performed with TiO2 and ZnO nanoparticles at a concentration of 1 gL-1 . These assays were performed in deionized water containing perfluorohexanoic acid or trifloxystrobin, both at a concentration of 10 and 1 mgL-1 . It was verified by potentiometry, that the treatment with ZnO nanoparticles led to the defluorination of 27% of trifloxystrobin in 6 hours. On the other hand, treatment of perfluorohexanoic acid and trifloxystrobin (1 mgL-1 ) by the synthetic consortium resulted in no biodegradation. Finally, when the technology was tested together, the synthetic consortium was capable of defluorinating a small percentage of trifloxystrobin (4.7%). In conclusion, although strains capable of degrading fluorinated compounds were found, they were not able to degrade PFAS when included in a synthetic consortium. Nano-photocatalysis by ZnO nanoparticles, on the other hand, showed a potential degradation of trifloxystrobin. By combining these two technologies, a defluorination percentage of about 30% was obtained.
Today, many substances pose a serious threat to human and ecological health. Due to their persistence, bioaccumulation, and possible negative consequences, PFAS have emerged as particularly worrying among these pollutants. PFAS, have been widely found in aquatic ecosystems. Since these ecosystems are an essential habitat for a wide variety of creatures and a crucial supply of drinking water for human societies, this poses a substantial ecological problem. This study aimed to develop a hybrid remediation technology for the removal of PFAS from aquatic matrices using nanophotocatalysis and bioremediation. Several strains were tested for their capabilities of degrading fluorinated compounds to create a consortium with potential do degrade PFAS resultant from the nanophotocatalysis treatment. Strain COL5 showed complete defluorination of sodium fluoroacetate, as did strain F11 but for the compound fluorobenzene, both at a concentration of 50 mgL-1 . Strain 3EE was able to defluorinate 17% of the compound epoxiconazole at 5 mgL-1 , and strain DPS8 defluorinated 20% of paroxetine at 1 mgL-1 . Biocompatibility between the strains showing the best defluorination performances was studied, but due to contamination, it was not possible to verify compatibility between them. The nanophotocatalysis experiments were performed with TiO2 and ZnO nanoparticles at a concentration of 1 gL-1 . These assays were performed in deionized water containing perfluorohexanoic acid or trifloxystrobin, both at a concentration of 10 and 1 mgL-1 . It was verified by potentiometry, that the treatment with ZnO nanoparticles led to the defluorination of 27% of trifloxystrobin in 6 hours. On the other hand, treatment of perfluorohexanoic acid and trifloxystrobin (1 mgL-1 ) by the synthetic consortium resulted in no biodegradation. Finally, when the technology was tested together, the synthetic consortium was capable of defluorinating a small percentage of trifloxystrobin (4.7%). In conclusion, although strains capable of degrading fluorinated compounds were found, they were not able to degrade PFAS when included in a synthetic consortium. Nano-photocatalysis by ZnO nanoparticles, on the other hand, showed a potential degradation of trifloxystrobin. By combining these two technologies, a defluorination percentage of about 30% was obtained.
Description
Keywords
Aquatic environment Pollution PFAS consortium Nanophotocatalysis Biodegradation