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| 1. |  | TEIXEIRA, V. A.; ARAUJO, G. S. C.; ALVES, M. P. A.; VANZ, A.; CORREA, C. R. L.; SILVA, A. N. B.; CASTRO, A. A. Características dos ciclones que causam desastres naturais em Santa Catarina: um estudo de caso. In: CONGRESSO BRASILEIRO DE METEOROLOGIA, 17., 2012, Gramado, RS. Anais.... Rio de Janeiro: SBMET, 2012.| Biblioteca(s): Epagri-Sede. |
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| 2. | | TEIXEIRA, V.; ARAUJO, G. S. C.; CARDOSO, C. S.; CORREA, C. R. L.; ESKELSEN, M.; SILVA, A. N. B.; RODRIGUES, M. L. G.; BITENCOURT, D. Sistema de Identificação e Previsão de Ciclone Extratropical no Sudeste da America do Sul. In: SIMPÓSIO INTERNACIONAL DE CLIMATOLOGIA, 4., 2011, João Pessoa, PB. Mudanças Climáticas e seus Impactos em àreas Urbanas: anais... Rio de Janeiro: SBMET, 2011.| Biblioteca(s): Epagri-Sede. |
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| Registros recuperados : 2 | |
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Registro Completo
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Biblioteca(s): |
Epagri-Sede. |
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Data corrente: |
17/10/2022 |
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Data da última atualização: |
17/10/2022 |
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Tipo da produção científica: |
Resumo em Anais de Congresso |
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Autoria: |
SCHUTT, S. Q.; METZ, D. C. H. P.; REBELO, A. M.; ZIMMERMANN, L. M. |
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Título: |
Efficient degradation of cationic dyes and agrochemicals by ZnO and ZnO-Fe(III) nanoparticles under natural sunlight and UV light. |
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Ano de publicação: |
2022 |
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Fonte/Imprenta: |
In: LATIN AMERICAN CONFERENCE ON PHYSICAL ORGANIC CHEMISTRY, 15., 2022, Florianópolis. Resumos... Florianópolis: UFSC , 2022. |
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Idioma: |
Inglês |
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Conteúdo: |
Zinc oxide quantum dots (QDs) and nanoparticles (NPs) are very attractive to many applications due to their optical and electronic properties, low-cost, high surface area, and low toxicity. ZnO QDs have reduced sizes, in the magnitude of the Bohr radius (~2-5 nm) inside the 3D quantum confinement effect. NPs have larger ranges of size and shapes. Among the applications, ZnO has been applied in photocatalysis for degradation or organic pollutants. Efficient degradation of dyes used in textile dyeing processes, as well as the degradation of pesticides are important environmental requirements. The degradation efficiency of two cationic dyes under natural sunlight and UV light in the presence of ZnO and ZnO:Fe(III) QDs was investigated. Besides, the photocatalytic degradation of the pesticide pyraclostrobin (PYR) was investigated with a colloidal dispersion of ZnO NPs. ZnO NPs were prepared by sol-gel from the precursors Zn(CH3COO)2·2H2O and KOH, at 7.310-2 mol L-1 and 0.1 mol L-1, respectively. QDs were prepared in ethanol from Zn(CH3COO)2·2H2O and NaOH, at 2.010-3 mol L-1 and 2.510-3 mol L-1, respectively. Fe(NO3)3·9H2O was also added as a precursor in the reaction medium, being equivalent to the mol% of 0.02%, 0.04% and 0.07%. Photocatalytic assays of cationic dyes, methylene blue (MB) and astrazon blue FGGL 300% (AB), were carried out in the same environment of the synthesis under natural sunlight and UV light (250W) monitoring the absorption at max. Photodegradation of PYR was carried out by redispersion of ZnO NPs in distilled water and PYR at 0.2 mg L-1 under UV light (125 W) monitoring the fluorescence intensity at 348 nm. TEM images showed that ZnO:Fe(III) QDs are smaller than ZnO QDs, 3.9 ± 0.2 nm and 4.3 ± 0.1 nm, respectively. Recently it was demonstrated that for a ZnO concentration at 2.010-3 mol L-1, the magnitude of QDs concentration is 10-6 mol L-1. Results for photodegradatjon of cationic dyes, Fe(III)-doped ZnO QDs with 0.04 mol% gave the highest apparent rate constants (Fig. 1) with degradation percentage equal to 84.3% and 66.9%, MB and AB, respectively, after 7 min under sunlight irradiation. Experiments were carried out with scavengers for hydroxyl (OH) and anion superoxide (O2-)radicals, tert-butanol and 1,4-benzoquinone (1,4-BQ), respectively. MB degradation course did not change in the ethanolic medium, known as OH scavenger, as well as with an extra amount of tert-butanol. However, the photocatalytic efficiency strongly decreased under the presence of 1,4-BQ. Thus, it is assumed that the MB degradation route in ethanol occurs mainly through the radical species O2-. By monitoring PYR emission, partial results indicate pesticide degradation (Fig. 2). Chromatographic assays will be performed to elucidate the process. Through the mass spectra, it was possible to identify a breakdown of MB molecule after the photocatalysis procedures, obtaining the lowest values of m/z for the photodegradation performed with 0.04% ZnO-Fe (III) QDs. For AB, the mass spectra suggest a discoloration of the sample by breaking the double bond existing in the azo group of the molecule. Fe(III) content prevents the recombination of the electron-hole pairs and reduces the diameter of the QDs, increasing the photocatalytic efficiency. The study proved to be very sustainable and eco-friendly, being carried out in an ethanolic environment, in the case of the cationic dyes and with natural sunlight. This strategy ensured maximum surface efficiency and photocatalytic activity. MenosZinc oxide quantum dots (QDs) and nanoparticles (NPs) are very attractive to many applications due to their optical and electronic properties, low-cost, high surface area, and low toxicity. ZnO QDs have reduced sizes, in the magnitude of the Bohr radius (~2-5 nm) inside the 3D quantum confinement effect. NPs have larger ranges of size and shapes. Among the applications, ZnO has been applied in photocatalysis for degradation or organic pollutants. Efficient degradation of dyes used in textile dyeing processes, as well as the degradation of pesticides are important environmental requirements. The degradation efficiency of two cationic dyes under natural sunlight and UV light in the presence of ZnO and ZnO:Fe(III) QDs was investigated. Besides, the photocatalytic degradation of the pesticide pyraclostrobin (PYR) was investigated with a colloidal dispersion of ZnO NPs. ZnO NPs were prepared by sol-gel from the precursors Zn(CH3COO)2·2H2O and KOH, at 7.310-2 mol L-1 and 0.1 mol L-1, respectively. QDs were prepared in ethanol from Zn(CH3COO)2·2H2O and NaOH, at 2.010-3 mol L-1 and 2.510-3 mol L-1, respectively. Fe(NO3)3·9H2O was also added as a precursor in the reaction medium, being equivalent to the mol% of 0.02%, 0.04% and 0.07%. Photocatalytic assays of cationic dyes, methylene blue (MB) and astrazon blue FGGL 300% (AB), were carried out in the same environment of the synthesis under natural sunlight and UV light (250W) monitoring the absorption at... Mostrar Tudo |
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Thesagro: |
photocatalysis under sun and UV light; pyraclostrobin; quantum dots; textile dyes. |
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Categoria do assunto: |
X Pesquisa, Tecnologia e Engenharia |
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Marc: |
LEADER 04360naa a2200205 a 4500
001 1132606
005 2022-10-17
008 2022 bl uuuu u00u1 u #d
100 1 $aSCHUTT, S. Q.
245 $aEfficient degradation of cationic dyes and agrochemicals by ZnO and ZnO-Fe(III) nanoparticles under natural sunlight and UV light.$h[electronic resource]
260 $c2022
520 $aZinc oxide quantum dots (QDs) and nanoparticles (NPs) are very attractive to many applications due to their optical and electronic properties, low-cost, high surface area, and low toxicity. ZnO QDs have reduced sizes, in the magnitude of the Bohr radius (~2-5 nm) inside the 3D quantum confinement effect. NPs have larger ranges of size and shapes. Among the applications, ZnO has been applied in photocatalysis for degradation or organic pollutants. Efficient degradation of dyes used in textile dyeing processes, as well as the degradation of pesticides are important environmental requirements. The degradation efficiency of two cationic dyes under natural sunlight and UV light in the presence of ZnO and ZnO:Fe(III) QDs was investigated. Besides, the photocatalytic degradation of the pesticide pyraclostrobin (PYR) was investigated with a colloidal dispersion of ZnO NPs. ZnO NPs were prepared by sol-gel from the precursors Zn(CH3COO)2·2H2O and KOH, at 7.310-2 mol L-1 and 0.1 mol L-1, respectively. QDs were prepared in ethanol from Zn(CH3COO)2·2H2O and NaOH, at 2.010-3 mol L-1 and 2.510-3 mol L-1, respectively. Fe(NO3)3·9H2O was also added as a precursor in the reaction medium, being equivalent to the mol% of 0.02%, 0.04% and 0.07%. Photocatalytic assays of cationic dyes, methylene blue (MB) and astrazon blue FGGL 300% (AB), were carried out in the same environment of the synthesis under natural sunlight and UV light (250W) monitoring the absorption at max. Photodegradation of PYR was carried out by redispersion of ZnO NPs in distilled water and PYR at 0.2 mg L-1 under UV light (125 W) monitoring the fluorescence intensity at 348 nm. TEM images showed that ZnO:Fe(III) QDs are smaller than ZnO QDs, 3.9 ± 0.2 nm and 4.3 ± 0.1 nm, respectively. Recently it was demonstrated that for a ZnO concentration at 2.010-3 mol L-1, the magnitude of QDs concentration is 10-6 mol L-1. Results for photodegradatjon of cationic dyes, Fe(III)-doped ZnO QDs with 0.04 mol% gave the highest apparent rate constants (Fig. 1) with degradation percentage equal to 84.3% and 66.9%, MB and AB, respectively, after 7 min under sunlight irradiation. Experiments were carried out with scavengers for hydroxyl (OH) and anion superoxide (O2-)radicals, tert-butanol and 1,4-benzoquinone (1,4-BQ), respectively. MB degradation course did not change in the ethanolic medium, known as OH scavenger, as well as with an extra amount of tert-butanol. However, the photocatalytic efficiency strongly decreased under the presence of 1,4-BQ. Thus, it is assumed that the MB degradation route in ethanol occurs mainly through the radical species O2-. By monitoring PYR emission, partial results indicate pesticide degradation (Fig. 2). Chromatographic assays will be performed to elucidate the process. Through the mass spectra, it was possible to identify a breakdown of MB molecule after the photocatalysis procedures, obtaining the lowest values of m/z for the photodegradation performed with 0.04% ZnO-Fe (III) QDs. For AB, the mass spectra suggest a discoloration of the sample by breaking the double bond existing in the azo group of the molecule. Fe(III) content prevents the recombination of the electron-hole pairs and reduces the diameter of the QDs, increasing the photocatalytic efficiency. The study proved to be very sustainable and eco-friendly, being carried out in an ethanolic environment, in the case of the cationic dyes and with natural sunlight. This strategy ensured maximum surface efficiency and photocatalytic activity.
650 $aphotocatalysis under sun and UV light
650 $apyraclostrobin
650 $aquantum dots
650 $atextile dyes
700 1 $aMETZ, D. C. H. P.
700 1 $aREBELO, A. M.
700 1 $aZIMMERMANN, L. M.
773 $tIn: LATIN AMERICAN CONFERENCE ON PHYSICAL ORGANIC CHEMISTRY, 15., 2022, Florianópolis. Resumos... Florianópolis: UFSC , 2022.
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