Degradation of sulphamethazine by means of an improved photo-Fenton process involving a hydrogen peroxide systematic dosage

Yamal-Turbay, Evelyn; González, Lydia Pérez; Graells, Moisès; Pérez-Moya, Montserrat

doi:10.1080/09593330.2014.880516

Cited by 7 publications

(2 citation statements)

References 27 publications

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“…The stoichiometric H 2 O 2 concentration of 118.7 mg L −1 could be used in order to achieve faster initial conversion, then adding extra H 2 O 2 dosage during the course of the assay, in order to keep the initial efficiency of the assay C (118.7_ON). The result of this H 2 O 2 addition (H 2 O 2 dosage) would increase the efficiency of the process, because of better use of the Fenton reagent, as already reported by other authors [38].…”

Section: Sulfaquinoxaline Oxidationsupporting

confidence: 67%

Sulfaquinoxaline Oxidation and Toxicity Reduction by Photo-Fenton Process

Urbano

Maniero

Guimarães

et al. 2021

IJERPH

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Sulfaquinoxaline (SQX) has been detected in environmental water samples, where its side effects are still unknown. To the best of our knowledge, its oxidation by Fenton and photo-Fenton processes has not been previously reported. In this study, SQX oxidation, mineralization, and toxicity (Escherichia coli and Staphylococcus aureus bacteria) were evaluated at two different setups: laboratory bench (2 L) and pilot plant (15 L). The experimental design was used to assess the influence of the presence or absence of radiation source, as well as different H2O2 concentrations (94.1 to 261.9 mg L−1). The experimental conditions of both setups were: SQX = 25 mg L−1, Fe(II) = 10 mg L−1, pH 2.8 ± 0.1. Fenton and photo-Fenton were suitable for SQX oxidation and experiments resulted in higher SQX mineralization than reported in the literature. For both setups, the best process was the photo-Fenton (178.0 mg L−1 H2O2), for which over 90% of SQX was removed, over 50% mineralization, and bacterial growth inhibition less than 13%. In both set-ups, the presence or absence of radiation was equally important for sulfaquinoxaline oxidation; however, the degradation rates at the pilot plant were between two to four times higher than the obtained at the laboratory bench.

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Section: Sulfaquinoxaline Oxidationsupporting

confidence: 67%

Sulfaquinoxaline Oxidation and Toxicity Reduction by Photo-Fenton Process

Urbano

Maniero

Guimarães

et al. 2021

IJERPH

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“…No entanto, após a exaustão do H2O2, a conversão máxima (ξmax = 0,81) foi menor que nos ensaios E e F (ξmax = 0,92), por exemplo. Isso sugere que uma melhor condição experimental poderia ser aplicada no início do ensaio; utilizando 119 mg L -1 de H2O2 para atingir uma rápida conversão inicial, e em seguida adicionar doses extra de H2O2 ao longo do tempo de reação para manter a eficiência inicial obtida no ensaio C. O aumento na eficiência devido à dosagem adicional de H2O2 já foi reportado por outros autores(YAMAL-TURBAY et al, 2014b). Pareto foi usado para determinar o efeito de cada variável nos fatores de resposta e os resultados obtidos tanto em escala de laboratório quanto para a planta piloto são apresentados na Tabela 8.1.…”

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Processos oxidativos avançados aplicados à degradação de sulfaquinoxalina

Urbano¹

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Sulfaquinoxaline (SQX), which belongs to the sulfonamides' class, is a synthetic antimicrobial and bacteriostatic agent used in animals for prevention of coccidiosis and bacterial infections. Due to its low adsorption on soil, it is usually found in water matrices. Since the conventional wastewater treatment plants do not degrade it efficiently, this compound has been detected on the environment. The advanced oxidation processes (AOP), generates hydroxyl radicals (HO • ), and are efficient on sulfonamide's degradation. This work evaluated the sulfaquinoxaline degradation (initial concentration: 500 µg L -1 ) by peroxidation (H2O2), photolysis (UV), peroxidation assisted by ultraviolet radiation (UV/H2O2), ozonation in basic medium (O3/HO -), photocatalysis (UV/TiO2, UV/TiO2/H2O2), Fenton's reagent (Fe 2+ /H2O2) and photo-Fenton (UV/Fe 2+ /H2O2). SQX quantification was performed using high performance liquid chromatography-diode array detection (HPLC-DAD) and the degradation products were evaluated by high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS). The solutions submitted to the degradation processes were evaluated according to the antimicrobial activity using Escherichia coli and Staphylococcus aureus bacteria, and toxicity using Vibrio fischeri bacterium. The peroxidation process degraded less than 5% SQX. The photolysis process degraded 58% SQX after 14 min of reaction and the solutions submitted to this process inhibited approximately 8% of Vibrio fischeri luminescence. The AOPs were efficient on SQX degradation: 99% of its initial concentration was degraded at least in one of the experimental conditions tested. At the processes UV/TiO2 (TiO2: 20 to 100 mg L -1 ) and UV/TiO2/H2O2 (TiO2: 5 and 100 mg L -1 / H2O2: 0.8 mmol L -1 ) more than 99% SQX was degraded after 11 min of reaction. At the process UV/H2O2 (H2O2: 9 mmol L -1 ) 99.6% of SQX was degraded after 11.4 min of reaction. For all the pH values evaluated on the ozonation process (3, 7, and 11), more than 99% SQX was degraded; and the ozone demand was low at pH 3 value, and the solutions treated did not present residual toxicity. The toxicity of the solutions submitted to the processes UV/TiO2, UV/TiO2/H2O2, UV/H2O2 and O3/HOincreased, reaching 94% of luminescence inhibition of Vibrio fischeri bacterium at the process UV/TiO2 (TiO2: 5 mg L -1 ). The degradation products of SQX were classified as toxic and persistent, and their chemical structures were proposed. The processes Fenton's reagent and photo-Fenton were evaluated in two reactors, laboratory bench (2 L) and pilot scale (15 L). The efficiency of SQX degradation (initial concentration: 25 mg L -1 ) was very similar between the reactors, 92% at laboratory bench and 95% at pilot scale. No inhibition of bacteria growth was after submitting the solutions to Fenton's reagent and photo-Fenton processes. At laboratory bench, the presence or absence of radiation was more significant to mineralization, and the interaction of this variable with the variable H2O2 concentrati...

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