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Photo-Degradation of Contaminants as a Way of Remediation of Aquaculture's Water = = Foto-degradacao de contaminantes como meio de remediacao de aguas de aquacultura.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Photo-Degradation of Contaminants as a Way of Remediation of Aquaculture's Water =/
Reminder of title:	Foto-degradacao de contaminantes como meio de remediacao de aguas de aquacultura.
Author:	Leal, Joana Ferreira.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2019,
Description:	220 p.
Notes:	Source: Dissertations Abstracts International, Volume: 81-11, Section: B.
Contained By:	Dissertations Abstracts International81-11B.
Subject:	Aquatic sciences. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27933855
ISBN:	9781658480949

Photo-Degradation of Contaminants as a Way of Remediation of Aquaculture's Water = = Foto-degradacao de contaminantes como meio de remediacao de aguas de aquacultura.
Leal, Joana Ferreira.

Photo-Degradation of Contaminants as a Way of Remediation of Aquaculture's Water =Foto-degradacao de contaminantes como meio de remediacao de aguas de aquacultura. - Ann Arbor : ProQuest Dissertations & Theses, 2019 - 220 p.

Source: Dissertations Abstracts International, Volume: 81-11, Section: B.

Thesis (Ph.D.)--Universidade de Aveiro (Portugal), 2019.

This item must not be sold to any third party vendors.

As result of an increase in fish consumption and fisheries stagnation, aquaculture is a growing and widespread activity. The increasing density in aquaculture production potentiates the appearance of pathogenic microorganisms, like bacteria, requiring a greater health control, achieved with disinfectants. In some cases, the use of antibiotics may be necessary. In this work, two chemical compounds approved for aquaculture are studied: oxytetracycline (antibiotic) and formalin (disinfectant). In addition to the intentionally introduced compounds, several others reach these water systems indirectly. As example of an indirect contaminant, decabromodiphenyl ether (BDE-209) was also included in this study. The photo-degradation under sunlight is one of the main routes of natural degradation of contaminants in surface waters and may be an economic process for treatment of contaminated waters before their reuse or discharge. However, this process is influenced by water matrix, namely the nature and concentration of organic matter and salts. Under the direct action of sunlight, BDE-209 and oxytetracycline (OTC) are rapidly degraded. However, in the presence of humic substances (HS), which are the main components of organic matter, the degradation of these two compounds is delayed. While the filter effect of light explains the delay on OTC photo-degradation, in the case of BDE-209, the hydrophobic interactions between the compound and the HS are the main reason for the delay. Salts and pH of marine aquaculture's water favour the OTC photo-degradation relatively to deionized water. Calcium and magnesium have a strong influence on the kinetics and products of OTC photo-degradation. It should be noted that, in all saline matrices, the products resulting from OTC photo-degradation revealed no biological activity for E. coli, Aeromonas sp. and Vibrio sp., which is an advantage in what the bacterial resistance to this antibiotic is concerned. Formalin (aqueous formaldehyde) undergoes only indirect photo-degradation. Neat TiO2 and two visible light active TiO2 composites (TiO2-Tetra-phenyl porphyrin and TiO2-Graphene oxide) were tested as photo-catalysts. The combination of TiO2 with graphene oxide was the best choice for formalin degradation, under sunlight. However, the methodology proposed should be optimized in view of its application to marine aquaculture's waters since the matrix of these waters reduces the photo-catalyst efficiency. In summary, the work carried out and disclosed herein has great application potential, especially in the aquaculture industry, but also in other water systems where these contaminants are present.

ISBN: 9781658480949Subjects--Topical Terms:

3174300
Aquatic sciences.
Subjects--Index Terms:

aquaculture

Photo-Degradation of Contaminants as a Way of Remediation of Aquaculture's Water = = Foto-degradacao de contaminantes como meio de remediacao de aguas de aquacultura.
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500 $a Source: Dissertations Abstracts International, Volume: 81-11, Section: B.
502 $a Thesis (Ph.D.)--Universidade de Aveiro (Portugal), 2019.
506 $a This item must not be sold to any third party vendors.
520 $a As result of an increase in fish consumption and fisheries stagnation, aquaculture is a growing and widespread activity. The increasing density in aquaculture production potentiates the appearance of pathogenic microorganisms, like bacteria, requiring a greater health control, achieved with disinfectants. In some cases, the use of antibiotics may be necessary. In this work, two chemical compounds approved for aquaculture are studied: oxytetracycline (antibiotic) and formalin (disinfectant). In addition to the intentionally introduced compounds, several others reach these water systems indirectly. As example of an indirect contaminant, decabromodiphenyl ether (BDE-209) was also included in this study. The photo-degradation under sunlight is one of the main routes of natural degradation of contaminants in surface waters and may be an economic process for treatment of contaminated waters before their reuse or discharge. However, this process is influenced by water matrix, namely the nature and concentration of organic matter and salts. Under the direct action of sunlight, BDE-209 and oxytetracycline (OTC) are rapidly degraded. However, in the presence of humic substances (HS), which are the main components of organic matter, the degradation of these two compounds is delayed. While the filter effect of light explains the delay on OTC photo-degradation, in the case of BDE-209, the hydrophobic interactions between the compound and the HS are the main reason for the delay. Salts and pH of marine aquaculture's water favour the OTC photo-degradation relatively to deionized water. Calcium and magnesium have a strong influence on the kinetics and products of OTC photo-degradation. It should be noted that, in all saline matrices, the products resulting from OTC photo-degradation revealed no biological activity for E. coli, Aeromonas sp. and Vibrio sp., which is an advantage in what the bacterial resistance to this antibiotic is concerned. Formalin (aqueous formaldehyde) undergoes only indirect photo-degradation. Neat TiO2 and two visible light active TiO2 composites (TiO2-Tetra-phenyl porphyrin and TiO2-Graphene oxide) were tested as photo-catalysts. The combination of TiO2 with graphene oxide was the best choice for formalin degradation, under sunlight. However, the methodology proposed should be optimized in view of its application to marine aquaculture's waters since the matrix of these waters reduces the photo-catalyst efficiency. In summary, the work carried out and disclosed herein has great application potential, especially in the aquaculture industry, but also in other water systems where these contaminants are present.
520 $a A aquacultura e uma atividade em crescente expansao em resultado do aumento do consumo de peixe e da estagnacao das pescas. O aumento da densidade de producao em aquacultura potencia o aparecimento de microrganismos patogenicos, como as bacterias, obrigando a um maior controlo sanitario que e feito com desinfetantes. Em alguns casos, pode ser necessario o uso de antibioticos. Neste trabalho sao estudados dois compostos quimicos autorizados em aquacultura: a oxitetraciclina (antibiotico) e a formalina (desinfetante). Alem dos compostos introduzidos intencionalmente, existem outros que, por via indireta, atingem estes sistemas aquaticos. Como exemplo de um contaminante indireto, o eter deca-bromodifenilo (BDE-209) foi tambem incluido neste estudo. A foto-degradacao com luz solar e uma das principais vias de degradacao natural de contaminantes em aguas superficiais e pode constituir uma via economica para o tratamento de aguas contaminadas antes da sua descarga ou reutilizacao. Contudo, este e um processo influenciado pela matriz das aguas, nomeadamente pela concentracao e natureza da materia organica e pelos sais. Sob a acao direta da luz solar, o BDE-209 e a oxitetraciclina (OTC) sao degradados rapidamente. Contudo, na presenca de substancias humicas (HS), que sao as principais componentes da materia organica, a degradacao de ambos e retardada. Enquanto o efeito de filtro da luz explica o atraso da foto-degradacao da OTC, no caso do BDE-209, as interacoes hidrofobicas entre o composto e as HS sao a razao principal desse atraso. Os sais e o pH das aguas de aquacultura marinha favorecem a foto-degradacao da OTC relativamente a agua desionizada. O calcio e o magnesio tem uma forte influencia na cinetica e nos produtos de foto-degradacao da OTC. Importa salientar que, em todas as matrizes salinas, os produtos resultantes da foto-degradacao da OTC nao revelaram atividade biologica para a E. coli, Aeromonas sp. e Vibrio sp., o que e uma vantagem no que diz respeito a resistencia bacteriana a este antibiotico. A formalina (formaldeido aquoso) apenas sofre foto-degradacao indireta. O TiO2 puro e dois compositos de TiO2 ativos na zona visivel (TiO2-Tetra-fenilo porfirina e TiO2-oxido de grafeno) foram testados como foto-catalisadores. A conjugacao de TiO2 com oxido de grafeno revelou-se a melhor escolha para a degradacao da formalina, usando luz solar. Contudo, a metodologia proposta devera ser otimizada com vista a sua aplicacao a aguas de aquacultura marinha, uma vez que a matriz destas aguas reduz a eficiencia do foto-catalisador. Em suma, o trabalho desenvolvido e aqui apresentado tem grande potencialidade de aplicacao, em particular no setor da aquacultura, mas tambem em outros sistemas aquaticos onde estes contaminantes estejam presentes.
590 $a School code: 5890.
650 4 $a Aquatic sciences. $3 3174300
650 4 $a Chemical oceanography. $3 516760
650 4 $a Organic chemistry. $3 523952
653 $a aquaculture
653 $a Fishery sciences
653 $a Photodegradation
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710 2 $a Universidade de Aveiro (Portugal). $3 1256647
773 0 $t Dissertations Abstracts International $g 81-11B.
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