Detalhes bibliográficos
| Ano de defesa: |
2024 |
| Autor(a) principal: |
Menezes, Luíza Bôlla de |
| Orientador(a): |
Silva , William Leonardo da |
| Banca de defesa: |
Baldez, Raisi Natalia Lenz,
Silva , Maurício Dalla Costa Rodrigues da |
| Tipo de documento: |
Dissertação
|
| Tipo de acesso: |
Acesso embargado |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Franciscana
|
| Programa de Pós-Graduação: |
Programa de Pós-Graduação em Nanociências
|
| Departamento: |
Biociências e Nanomateriais
|
| País: |
Brasil
|
| Palavras-chave em Português: |
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| Palavras-chave em Inglês: |
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| Área do conhecimento CNPq: |
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| Link de acesso: |
http://www.tede.universidadefranciscana.edu.br:8080/handle/UFN-BDTD/1289
|
Resumo: |
Synthetic dyes are substances widely used in the textile and food industries and, when present in wastewater, reduce the incidence of light, which causes destabilization of the aquatic ecosystem. Tartrazine yellow (AT) is a primary dye used both for yellow coloring and for the formation of other product colors. As it is an azo dye, it has great chemical stability, making it difficult to remove using conventional wastewater treatment methods (physical-chemical and biological). Therefore, Advanced Oxidative Processes (AOPs), especially heterogeneous photocatalysis, stand out as a viable alternative for wastewater treatment, since its process is based on the generation of hydroxyl radicals (●OH), with high oxidizing power, capable of degrading synthetic dyes. In this context, the present work aimed to synthesize and characterize calcium oxide nanoparticles (CaO-NPs) from golden flaxseed extract (Linum usitatissimum L.), for application in the degradation of AT dye, as well as evaluation of their toxicity (phytotoxicity and ecotoxicity in soil) and in vitro safety profile. The samples were characterized by X-ray diffraction (XRD), N2 porosimetry (BET/BJH), zeta potential (PZ), point of zero charge (pHPCZ), high-resolution electron microscopy (SEM-FEG), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). The experimental design of the rotational central compound (DCCR 23) was carried out to determine the ideal condition of the photocatalytic process, where the evaluated variables were pH, dye concentration and nanocatalyst concentration. Phytotoxicity analyses were performed on Daucus carota, Beet shankar, Lactuca sativa and Brassica oleracea seeds, as well as the in vitro safety profile performed on VERO lineage cells. The diffractograms indicated the characteristic presence of CaO at 32.22º (111), 37.35º (002), 53.83º (002) and 67.34º (112), in addition to calcium carbonate at 29.59º (001), 39.72º (030), 42.81º (012), 47.79º (202), 57.69º (116) and 64.09º (113). In addition, the nanomaterial presented mesoporous characteristics with a specific surface area of 14 m2g-1, pore diameter of 20.9 nm and pore volume of 0.054 cm3 g-1. The surface charge was positive (+12.7 ± 0.2 mV), with a zero charge point of 7.74. Regarding the morphology, the CaO-NPs presented an agglomeration with irregular particles of average size of 48 nm. In addition, the elemental composition obtained by EDS indicated the presence of CaO-NPs with 10.44% and 50.24% (by mass) for calcium and oxygen, respectively, in addition to the presence of 14.87% carbon, 3.33% aluminum, 3.32% magnesium, 2.29% iron and 0.63% potassium, from the phenolic components of golden flaxseed. The FITR-ATR spectrum indicated the presence of stretching from the golden linseed extract, such as methylene (C-H), aliphatic carbonyl (C=O), alkenes (C=C), saturated esters (C-O), as well as stretching of CaO NPs, such as Ca-O. Regarding the photocatalytic tests, CaO-NPs presented their best photocatalytic activity (around 76.16% under visible radiation) under the ideal condition of pH 7, [CaO-NPs] = 1.2 g L-1and [AT] = 20 mg L-1. Furthermore, toxicity analyses of the nanoparticles were performed, where CaO-NPs did not show acute toxicity against Daucus carota (wild carrot), Beet shankar (beetroot), Lactuca sativa (lettuce) and Brassica oleraea (cabbage) seeds in the range of 12.5 - 100 μg mL-1, showing a direct influence on seed germination and plant tissue growth. Regarding ecotoxicity in the soil, after 20 days, using XRD analysis, after the 12th day it was possible to verify the presence of CaO-NPs in the soil, with characteristic peaks at 37.35º (030) and 67.34º (113), indicating bioaccumulation for the highest concentrations (50 and 100 μg mL-1). Regarding the in vitro safety profile, CaO-NPs did not show a significant reduction in cell viability after 24 hours. However, after 72 hours, there was a reduction in cell proliferation at all concentrations of 15.9 ± 0.2%, 17.9 ± 0.2%, 17.6 ± 0.2%, 32.9 ± 0.2%, for 12.5, 25, 50 and 100 μg mL-1, respectively. Regarding the analysis of dsDNA release, it indicated that in the first 24 hours there was protection and controlled release within the cells. In addition, the levels of nitrates and nitrites were analyzed through the presence of nitric oxide (NO), where it was possible to observe that there was no transport of free electrons in the process of cell activation and inhibition. The presence of reactive oxygen species (ROS) is associated with inflammatory processes in cells, thus in 72 hours there was a reduction of 40 ± 0.2%, 33 ± 0.2%, 20 ± 0.2% and 9 ± 0.2%, for concentrations of 12.5, 25, 50 and 100 μg mL 1, respectively. However, when comparing the concentrations with the negative control, there was an increase of 50 ± 0.2%, 56 ± 0.2%, 77 ± 0.2%, and 92 ± 0.2%, in 12.5, 25, 50 and 100 μg mL-1, respectively, indicating that CaO-NPs produced free radicals. Therefore, it was possible to synthesize green metal oxide nanoparticles from golden linseed extract with potential properties for application in the removal of tartrazine yellow dye in solution, with low ecotoxicity in the soil and cytocompatibility, meeting the theme of sustainable development with nanotechnology. |
