Photodegradation of the aminoazobenzene acid orange 52 by three advanced oxidation processes: UV/H2O2, UV/TiO2 and VIS/TiO2

Galindo, Catherine; Jacques, Patrice; Kalt, André

doi:10.1016/s1010-6030(99)00199-9

Cited by 443 publications

(214 citation statements)

References 27 publications

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“…The literature on the chemical oxidation of azo dyes and the products found during LC-MS/MS analysis could be helpful for understanding the degradation pathways of dye I (8,14). Even though dye I is not a phenol azo dye that would be a typical substrate for laccase, extensive degradation was observed.…”

Section: Discussionmentioning

confidence: 99%

Degradation of Azo Dyes by Trametes villosa Laccase over Long Periods of Oxidative Conditions

Zille

Górnacka

Rehorek

et al. 2005

Appl Environ Microbiol

153

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Trametes villosa laccase was used for direct azo dye degradation, and the reaction products that accumulated after 72 h of incubation were analyzed. Liquid chromatography-mass spectrometry (LC-MS) analysis showed the formation of phenolic compounds during the dye oxidation process as well as a large amount of polymerized products that retain azo group integrity. The amino-phenol reactions were also investigated by 13 C-nuclear magnetic resonance and LC-MS analysis, and the polymerization character of laccase was shown. This study highlights the fact that laccases polymerize the reaction products obtained during long-term batch decolorization processes with azo dyes. These polymerized products provide unacceptable color levels in effluents, limiting the application of laccases as bioremediation agents.The chemical structure of dyes is comprised of a conjugated system of double bonds and aromatic rings. The major classes of dyes have antroquinoid, indigoid, and azo aromatic structures. All of these structures allow strong -* transitions in the UV-visible (UV-Vis) area, with high extinction coefficients that allow us to consider these structures dye chromophores. Of all of these structures, the azo aromatic one is the most widespread dye class in the industry. The main drawback of this class of dyes is that they are not easily degraded by aerobic bacteria, and with the action of anaerobic or microaerobic reductive bacteria, they can form toxic and/or mutagenic compounds such as aromatic amines (9, 10, 34). There is a great environmental concern about the fate of these dyes, with special emphasis on reactive dyeing of cellulosic fibers, where large amounts of unbound dye are discharged in the effluent (24).Laccases have been extensively studied for their degradation of azo dyes (1,5,8,17,19,21,23,33). These enzymes are multicopper phenol oxidases that decolorize azo dyes through a highly nonspecific free radical mechanism forming phenolic compounds, thereby avoiding the formation of toxic aromatic amines (8,35). Over long periods of time, there can be a coupling between the reaction products, and even polymerization. It is known that laccases can catalyze the polymerization of various halogen-, alkyl-, and alkoxy-substituted anilines (15). In the literature, there is a large number of papers reporting on the decolorization of azo dyes; however, the fate of the products of azo dye laccase reactions and their possible polymerization have been ignored (7,16,25,28). Therefore, the purpose of this work was the study of azo dye degradation products in the presence of laccase. Direct azo dye laccase degradation and amino-phenol polymerization were performed for several days. The formed soluble products were studied by liquid chromatography-mass spectrometry (LC-MS), and the polymerized insoluble products were studied by 13 C-nuclear magnetic resonance ( 13 C-NMR). MATERIALS AND METHODSDyes, reagents, and enzymes. The investigated dyes, 3-(4-dimethylamino-1-phenylazo) benzenesulfonic acid (dye I) and 3-(2-hydroxy-1-naphthyl...

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Section: Discussionmentioning

confidence: 99%

Degradation of Azo Dyes by Trametes villosa Laccase over Long Periods of Oxidative Conditions

Zille

Górnacka

Rehorek

et al. 2005

Appl Environ Microbiol

153

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“…Em geral, maior ênfase tem sido dado ao estabelecimento de metodologias que combinam os processos biológicos com outras alternativas físicas ou físico-químicas, tais como floculação, adsorção ou oxidação eletroquímica 8,90 . A combinação de processos oxidativos avançados (POAs) utilizando-se peróxido de hidrogênio, ozônio, luz ultravioleta, TiO 2 tem sido testados recentemente como alternativas aos processos de tratamento estabelecidos atualmente, com resultados promissores [91][92][93] . Processos físicos utilizando-se tecnologias de membranas combinadas principalmente com ozônio também tem recebido especial atenção no final da década de 90 devido a possibilidade de reuso da água conforme já discutido anteriormente 94,95 .…”

Section: Processos Combinadosunclassified

Novas tendências no tratamento de efluentes têxteis

Kunz¹,

Peralta‐Zamora²,

Moraes³

et al. 2002

Quím. Nova

340

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Recebido em 25/7/00; aceito em 6/6/01 NEW TENDENCIES ON TEXTILE EFFLUENT TREATMENT. Textile effluents, when not correctly treated, cause a high impact to the environment. The main recalcitrant compounds present in textile effluent are represented by the synthetic dyes, used during the fibber dying process. Among others, the azo dyes are considered the most harmful due to its mutagenic and carcinogenic character. In the present work we reported a revision study on the new tendencies for remediation of textile effluents, mainly to degrade the recalcitrant compounds. For this purpose, chemical, physical, photochemical, biological and combined processes were investigated.Keywords: textile effluents; treatment processes; recalcitrant compounds. INTRODUÇÃONas últimas décadas, os problemas ambientais têm se tornado cada vez mais críticos e freqüentes, principalmente devido ao desmedido crescimento populacional e ao aumento da atividade industrial. Com estes ingredientes os problemas devido a ação antrópica têm atingido dimensões catastróficas, podendo ser observadas através de alterações na qualidade do solo, ar e água.Sem dúvida, a contaminação de águas naturais tem sido um dos grandes problemas da sociedade moderna. A economia de água em processos produtivos vem ganhando especial atenção devido ao valor agregado que tem sido atribuído a este bem, através de princípios como consumidor pagador e poluidor pagador recentemente incorporados em nossa legislação. Aliado a isso, temos previsões não muito animadoras para o século que se inicia, como por exemplo a previsão feita pela Companhia de Saneamento do estado de São Paulo (SABESP), que estima que já em 2010 a demanda de água será superior a capacidade hídrica dos mananciais do estado 1 . Dentro deste contexto, o setor têxtil apresenta um especial destaque, devido a seu grande parque industrial instalado gerar grandes volumes de efluentes, os quais, quando não corretamente tratados, podem causar sérios problemas de contaminação ambiental.Os efluentes têxteis caracterizam-se por serem altamente coloridos, devido à presença de corantes que não se fixam na fibra durante o processo de tingimento 2 . A importância dos corantes para a civilização humana é evidente e bem documentada 3 . Os corantes sintéticos são extensivamente utilizados na indústria têxtil, gráfica, fotográfica e como aditivos em derivados de petróleo. Aproximadamente 10.000 diferentes corantes e pigmentos são usados industrialmente, o que representa um consumo anual de cerca de 7 x 10 5 tons no mundo 4-6 e 26.500 tons somente no Brasil 7 . A molécula do corante utilizada para tingimento da fibra têxtil pode ser dividida em duas partes principais, o grupo cromóforo e a estrutura responsável pela fixação à fibra.Existem vários grupos cromóforos utilizados atualmente na sín-tese de corantes. No entanto, o grupo mais representativo e largamente empregado pertence a família dos azocorantes (Figura 1), que se caracterizam por apresentarem um ou mais grupamentos -N=N-ligados a sistemas aromáticos. Os azocorantes r...

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“…The photoactivity of TiO 2 is altered by doping with transition metals like Pt, Pd, Au, Ag, Mn, Fe and Cu or oxides such as WO 3 , which act as charge separators of the photo-induced electron/hole pair (Arabatzis et al 2003;Arana et al 2005;Galindo et al 2000;Gracien et al 2007;Gupta et al 2006;Tokumura et al 2006;Zhao et al 2007). The combination of semiconductor substrate and metal cluster gives improved photocatalytic activity by trapping the photo-induced charge carriers, thereby improving the charge transfer processes (Nasr-Esfahani and Habibi 2008).…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic degradation of azo dye Orange II in aqueous solutions using copper-impregnated titania

Divya

Bansal

Jana

2013

Int. J. Environ. Sci. Technol.

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During dyeing process, industries consume large quantity of water and subsequently produce large volume of wastewater. This wastewater is rich in color and contains different dyes. Orange II is one of them. In this article, metal-impregnated TiO 2 P-25 catalyst was used to enhance the photocatalytic degradation of Orange II dye. Photodegradation percentage was followed spectrophotometrically by the measurements of absorbance at k max = 483 nm. The effect of copper-impregnated TiO 2 P-25 photocatalyst for the degradation of Orange II has been investigated in terms of percentage removal of color, chemical oxygen demand (COD) and total organic carbon (TOC). As such 98 % color removal efficiency, 97 % percentage removal of COD and 89 % percentage removal of TOC was achieved with TiO 2 P-25/Cu catalysts under typical conditions. Copper-impregnated TiO 2 P-25 photocatalyst showed comparatively higher activity than UV/ H 2 O 2 homogeneous photodegradation. The relative electrical energy consumption for photocatalytic degradation was considerably lower with TiO 2 P-25/Cu photocatalyst than that with homogeneous photodegradation. Transmission electron microscopic analysis was used for catalyst characterization.

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Photodegradation of the aminoazobenzene acid orange 52 by three advanced oxidation processes: UV/H2O2, UV/TiO2 and VIS/TiO2

Cited by 443 publications

References 27 publications

Degradation of Azo Dyes by Trametes villosa Laccase over Long Periods of Oxidative Conditions

Degradation of Azo Dyes by Trametes villosa Laccase over Long Periods of Oxidative Conditions

Novas tendências no tratamento de efluentes têxteis

Photocatalytic degradation of azo dye Orange II in aqueous solutions using copper-impregnated titania

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