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Avaliação eco/genotoxicológica dos corantes têxteis Reactive Blue 4 e Reactive Blue 15; Evaluation eco/genotoxicological of the textile dyes Reactive Blue 4 and Reactive Blue

Meireles, Gabriela
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/07/2013 PT
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Os corantes são amplamente utilizados nas indústrias têxteis, farmacêuticas, alimentícias, cosméticas, fotográficas, entre outras. Contudo, essas substâncias podem ser tóxicas, mutagênicas e resistentes a muitos processos de degradação utilizados em estações de tratamento. Estima-se que cerca de 15% dos corantes utilizados no mundo sejam perdidos durante o processo de tingimento e lançados no ambiente, atingindo principalmente os corpos d'água. No entanto, apesar da grande quantidade de corantes comerciais disponíveis e da alta quantidade lançada no ecossistema aquático, os estudos sobre a toxicidade dessas substâncias são escassos e pouco se conhece sobre seus efeitos mutagênicos e principalmente ecotoxicológicos. Dentro deste contexto, o objetivo do trabalho foi avaliar a ecotoxicidade, bem como a capacidade dos corantes têxteis Reactive Blue 4 (RB 4) e Reactive Blue 15 (RB 15) de lesar o material genético, empregando ensaios de toxicidade aguda com Daphnia similis e Vibrio fischeri, toxicidade crônica com Ceriodaphnia dubia, genotoxicidade (Teste do Cometa) com fibroblastos de derme humana e mutagenicidade com Salmonella typhimurium. Adicionalmente, avaliou-se a concentração de cobre em Ceriodaphnia dubia expostas ao corante Reactive Blue 15...

Studies of the voltammetric behavior and determination of diazo reactive dyes at mercury electrode

Guaratini, CCI; Fogg, A. G.; Zanoni, Maria Valnice Boldrin
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica Formato: 1535-1543
ENG
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The electrochemical reduction of two reactive dyes: Procion Red HE-3B 9 (RR120) and Procion Green HE-4BD (RG19) was investigated using cyclic voltammetry, differential pulse and DC, polarography, chronoamperometry and controlled potential electrolysis at mercury electrodes. The bis-azo groups of the RR120 dye are reduced together in one single step of four electrons, the bis-azo groups of the RG19 dye are reduced in two steps owing to the difference in the electron densities promoted by the different substituents in the benzene rings adjacent to the azo groups. The bis-monochlorotriazine reactive groups in both dyes are reduced only in acidic medium in their protonated form, leading to the reduction of the triazine groups. The reduction mechanism of both reactive dyes is discussed. Both dyes can be quantified in aqueous medium by differential pulse polarography in the concentration range of 1 x 10(-7) mol L-1 to 1 x 10(-5) mol L-1 by monitoring the reduction of the chromophore group or the reactive group.

Assessment of the application of cathodic stripping voltammetry to the analysis of diazo reactive dyes and their hydrolysis products

Guaratini, CCI; Fogg, A. G.; Zanoni, Maria Valnice Boldrin
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 211-221
ENG
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Two reactive dyes, C.I. Reactive Red 120 (RR120) and C.I. Reactive Green 19 (RG19), each bearing two azo groups as the chromophoric moiety and two monochloro-s-triazine groups as reactive groups, can be detected at nanomolar levels using cathodic stripping voltammetry. Linear calibration graphs were obtained for both reactive dyes, from 0.015 to 0.14 mu mol l(-1) for RR120 in pH 4 buffer and from 0.012 to 0.26 mu mol l(-1) for RG19 in pH 3 buffer, using a preconcentration at 0 V during 180 and 240 s on the mercury electrode, respectively. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Estudo da difusão de corantes reativos em tecido de algodão; Study of diffusion of reactive dyes on cotton fabric

Cristina Martins de Moraes
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 10/12/2010 PT
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O processo de tingimento destinado à área de acabamento nas indústrias têxteis tem relevada importância, onde o corante deve ter boa afinidade com as fibras para garantir a uniformidade da cor. O corante é o principal responsável pela poluição ambiental, já que apresenta elevada durabilidade, e são considerados de difícil degradação natural. Como atualmente as leis ambientais estão cada vez mais rígidas, preservando os recursos naturais, as indústrias tem buscado alternativas que minimizam os custos de tingimento e que reduzam os impactos ambientais. Uma melhor interação corante / fibras resulta em uma melhor transferência de massa de corante do banho para as fibras, devendo garantir que se atinja o equilíbrio do processo. Com a finalidade de determinar o grau de difusividade entre os corantes e a afinidade corante / fibras durante o processo de fixação, neste trabalho analisou-se o processo de difusão por meio dos quais os corantes reativos são adsorvidos nas fibras de algodão. Através dos ensaios experimentais, conseguiu-se determinar a concentração de corante / tempo sobre seu grau de esgotamento (equilíbrio) para quatro corantes distintos. Nos ensaios de tingimento determinou-se a concentração / tempo de cada corante no banho residual através da Espectrofotometria por meio de Absorbância e nas amostras de tecido obteve-se a quantidade de cor difundida nas mesmas pelo Método de Colorimetria...

Voltammetric study and electrochemical degradation of reactive dyes

Esteves, M. de Fátima; Cunha, Elisabete P.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 27/06/2005 ENG
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The aim of this study was, in a first stage, to investigate the voltammetric behavior of two reactive dyes, C.I.Reactive Orange 16 and C.I.Reactive Blue 19. Cyclic voltammetry technique (CV), on a glassy carbon electrode, was used for this purpose in order to identify the electrochemical activity of the chromophore group in each case, in the present experimental conditions. A second part of the study was to investigate the electrochemical degradation of the dyes, in the presence of hydrogen peroxide and copper ions. The reaction between the two species leads to the generation of hydroxyl radicals, which causes the oxidation and degradation of the organic compounds. The efficiency of dye degradation and ecolorization were evaluated by color removal and COD values. Depending on electrolysis time, applied potential, hydrogen peroxide concentration and dye concentration, different stages of color removal were attained.

Photodegradation studies on C. I. reactive red 158

Miranda, Teresa; Hrdina, Radim; Oldrich, Machalicky; Campos, Ana M. F. Oliveira
Fonte: Faculty of Textile Technology, University of Zagreb Publicador: Faculty of Textile Technology, University of Zagreb
Tipo: Conferência ou Objeto de Conferência
Publicado em 08/10/2006 ENG
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Dye-containing wastewater generated from textile industries is a major source of environmental pollution. Azo dyes, which are the largest group of coloring agents, are widely used in industry. Advanced Oxidative Processes are very promising for effluent treatment mainly due to their high efficiency and simplicity of operation. Our group became interested on photocatalytic methods (included in the AOP’s), using TiO2, for degradation of dyes, started with simpler structures and continued with commercial dyes. Titanium dioxide (TiO2) has proven to be the most effective and suitable catalyst for photocatalytic reaction due to its low cost economical, chemical stability, and insolubility. In this paper, the effects of UV light irradiation in the presence of TiO2 particles at various pH’s (3, 6, 8 and 10) on the photodegradation of an azo dye, Reactive Red 158, were investigated. The photocatalytic degradation was carried out either in aqueous solutions or in a synthetically prepared dyebath effluent, under UV irradiation, in the presence of Degussa P25 TiO2 as the catalyst. Reactive dyes of the pyrimidinyl type partly hydrolyse during dyeing in basic medium; RR 158 was hydrolysed and this solution was also irradiated. The fastest degradation was obtained with an acid solution (14 minutes...

A study on the spectral changes of reactive textile dyes and their implications for online control of dyeing processes

Santos, Jorge Gomes; Soares, Graça M. B.; Hrdina, Radim; Campos, Ana M. F. Oliveira; Gomes, Jaime Rocha
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em //2009 ENG
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Evidence is presented that confirms the colour changes of a widely used trichromatic mixture of bifunctional reactive dyes (Levafix CA) under alkaline conditions, showing that they occur slowly and throughout the dyeing time, and not instantly after alkali addition to the dyebath. Thus, it is impossible to determine the specific absorptivity of the dyes at each moment of the dyeing process. An investigation into the relationship of the type of reactive group to the dye and the visible spectral changes over time was undertaken. Model reactive dyes were studied. The samples collected from the simulated dyebaths were monitored online using an automated system and their absorption on the whole of the visible spectrum was measured. The studies of dyes that included halo-s-triazinyl groups revealed the existence of hypochromic shifts in the spectra of the dyes in the presence of an electrolyte (sodium chloride or sodium sulphate) and bathochromic and hyperchromic shifts, when evaluated in the presence of alkaline agents. However, the vinylsulphonyl derivatives present a more stable spectral profile. The use of buffer solution at pH 5 was an efficient method to stabilise the absorption profile of Levafix CA trichromatic samples.

Decolorization of salt-alkaline effluent with industrial reactive dyes by laccase-producing basidiomycetes strains

Moreira Neto, S. L.; Mussatto, Solange I.; Machado, K. M. G.; Milagres, Adriane M. F.
Fonte: Wiley; Blackwell Publishing Inc. Publicador: Wiley; Blackwell Publishing Inc.
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
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The discharge of highly coloured synthetic dye effluents into rivers and lakes is harmful to the water bodies, and therefore, intensive researches have been focussed on the decolorization of wastewater by biological, physical or chemical treatments. In the present study, 12 basidiomycetes strains from the genus Pleurotus, Trametes, Lentinus, Peniophora, Pycnoporus, Rigidoporus, Hygrocybe and Psilocybe were evaluated for decolorization of the reactive dyes Cibacron Brilliant Blue H-GR and Cibacron Red FN-2BL, both in solid and liquid media. Among the evaluated fungi, seven showed great ability to decolorize the synthetic textile effluent, both in vivo (74–77%) or in vitro (60–74%), and laccase was the main ligninolytic enzyme involved on dyes decolorization. Pleurotus ostreatus, Trametes villosa and Peniophora cinerea reduced near to 60% of the effluent colour after only 1 h of treatment. The decolorization results were still improved by establishing the nitrogen source and amount to be used during the fungal strains cultivation in synthetic medium previous their action on the textile effluent, with yeast extract being a better nitrogen source than ammonium tartarate. These results contribute for the development of an effective microbiological process for decolorization of dye effluents with reduced time of treatment.

Remoção de cor em soluções de corantes reativos por oxidação com H2O2/UV

Araujo,Fabiana Valéria da Fonseca; Yokoyama,Lídia; Teixeira,Luiz Alberto César
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2006 PT
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This paper summarizes the result of a degradation test of two azo-reactive dyes (Reactive Blue 214, Reactive Red 243) under UV irradiation in the presence of H2O2. Five different doses of hydrogen peroxide (0 mM, 5 mM, 10 mM, 20 mM and 30 mM) at constant initial concentration of the substrate (100 mg/L) were used. The radiation source were three 15 W-lamps. Complete destruction of the color of the solutions was attained in 40-50 min of irradiation. UV/H2O2 proved capable of complete discoloration and degradation of the above azo reactive dyes.

Electrochemical degradation of reactive dyes at different DSA® compositions

Silva,Rodrigo G. da; Aquino Neto,Sydney; Andrade,Adalgisa R. de
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
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This paper investigates the electrochemical oxidation of the reactive dyes reactive blue 4 (RB-4) and reactive orange 16 (RO-16) on RuO2 dimensionally stable anode (DSA®) electrodes. Electrolysis was achieved under galvanostatic control as a function of supporting electrolyte and electrode composition. The electrolyses, performed in either the presence or absence of NaCl, were able to promote efficient color removal; moreover, at low chloride concentration (0.01 mol L-1), total color removal was obtained after just 10 min of electrolysis, and a significant increase in total dye combustion was achieved for all the studied anodes in chloride medium (reaching ca. 80% - chemical oxygen demand - COD removal). No significant enhancement in dye color removal or mineralization was observed upon increasing chloride concentration. The influence of oxide composition on dye elimination seems to be significant in both media (with or without chloride), being Ti/Ru0.30Ti0.70O2, the most active material for organic compound oxidation. The oxygen evolution reaction (OER) was shown to be a limiting reaction in both supporting electrolytes; i.e., NaCl and Na2SO4, and its competition with organic compound oxidation remained an obstacle. The adsorbable organo halogens (AOX) formation study revealed that there is slight consumption of the undesirable species formed within the first minutes of the electrolysis...

Biodegradation of reactive textile dyes by basidiomycetous fungi from brazilian ecosystems

Machado,Kátia M.G.; Compart,Luciana C.A.; Morais,Rúbio O.; Rosa,Luiz H.; Santos,Mércia H.
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2006 EN
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The potential of Trametes villosa and Pycnoporus sanguineus to decolorize reactive textile dyes used for cotton manufacturing in the State of Minas Gerais, Brazil, was evaluated. Growth and decolorization halos were determined on malt extract agar containing 0.002g L-1 of the dye. T. villosa decolorized all 28 of the tested dyes while P. sanguineus decolorized only 9. The effect of culture conditions (shaking and dye and nitrogen concentration) on the degradation of Drimaren Brilliant Blue dye was evaluated during growth of the fungi in liquid synthetic medium. Shaking favored degradation and decolorization was not repressed by nitrogen. In pure culture, T. villosa and P. sanguineus decolorized synthetic effluent consisting of a mixture of 10 dyes. Higher decolorization of the synthetic effluent was observed when a mixed culture of the two fungi was used. This study demonstrated differences between tropical basidiomycete species in terms of their ability to degrade reactive dyes, and reinforces the potential of this group of fungi for the decolorization of textile effluents.

Clinical and immunological investigations of respiratory disease in workers using reactive dyes.

Docker, A; Wattie, J M; Topping, M D; Luczynska, C M; Newman Taylor, A J; Pickering, C A; Thomas, P; Gompertz, D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1987 EN
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A questionnaire survey of over 400 workers handling reactive dyes showed that over 15% had work related respiratory or nasal symptoms. Forty nine employees with symptoms were referred to chest clinics for detailed assessment. It was considered that in 19 the symptoms could be attributed to an irritant response to a variety of chemicals, including hydrochloric acid vapour, sulphur dioxide, and reactive dyes. Symptoms in 24 were attributed to an allergic reaction to a specific agent; in most (21) to one or more reactive dyes. Two patterns of allergic lower respiratory symptoms were identified; an immediate response of short duration and a longer lasting response, usually of several hours, sometimes accompanied by nocturnal asthma. A radioallergosorbent test (RAST) screen containing the most commonly used reactive dyes was used to detect specific IgE. Allergic symptoms to reactive dyes were strongly associated with specific IgE (17/21 employees) and atopy (18/21). Irritant symptoms were also associated with atopy (13/19) but only weakly associated with specific IgE (7/19).

Asthma, rhinitis, and dermatitis in workers exposed to reactive dyes.

Nilsson, R; Nordlinder, R; Wass, U; Meding, B; Belin, L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1993 EN
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A survey was conducted at 15 textile plants with dyehouses in western Sweden. Employees with a history of work related rhinitis, asthma, or skin symptoms were offered a clinical and immunological investigation including skin prick tests, skin patch tests, and radioallergosorbent tests (RASTs) to detect specific allergy to reactive dyes. Among the 1142 employees, 162 were exposed to reactive dyes and 10 of these (6%) reported work related respiratory or nasal symptoms. An allergy to reactive dyes could be confirmed in five (3%, 95% confidence interval 1-7%). All but one had been exposed to reactive dyes for one year or less before the onset of symptoms. Positive RASTs could be detected in four of the five patients. All of the RAST positive patients were positive to remazol black B, but six out of eight additional remazol dyes also elicited positive results. RAST and RAST inhibition showed a cross reactivity between some of the dyes. Seven persons with work related dermatitis and three with urticaria or Quincke oedema were found. In one patient contact dermatitis to a monoazo dye was shown, but no positive patch test reactions to reactive dyes. IgE-mediated allergy to reactive dyes seems to be an important cause of respiratory and nasal symptoms among dyehouse employees exposed to dust from reactive dyes.

Role of skin prick test and serological measurement of specific IgE in the diagnosis of occupational asthma resulting from exposure to vinyl sulphone reactive dyes

Park, J; Kim, C; Kim, K; Choi, S; Kang, D; Ko, S; Won, J; Yang, J; Hong, C
Fonte: BMJ Group Publicador: BMJ Group
Tipo: Artigo de Revista Científica
Publicado em /06/2001 EN
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OBJECTIVES—Some patients with occupational asthma resulting from exposure to reactive dyes have skin reactivity to the causative dyes and specific IgE to reactive dyes have been found in these patients. However, the usefulness of skin prick tests (SPTs) and serological measurement of specific IgE in screening, diagnosis, and monitoring the occupational asthma resulting from exposure to reactive dyes have not yet been assessed. In this study, the clinical validation of SPTs and measurement of specific IgE to vinyl sulphone reactive dyes by enzyme linked immunosorbent assay (ELISA) was evaluated.
METHODS— 42 Patients with occupational asthma from reactive dyes (true positive group) were enrolled. In these the causative reactive dye was confirmed by bronchial challenge test. 93 Asymptomatic factory workers with negative challenge to the reactive dye (true negative group) and 16 unexposed controls with negative challenge to the reactive dye were also enrolled. Skin prick tests were done with 10 mg/ml reactive dye in 0.4% phenol/0.9% saline. IgE specific to reactive dye conjugated to human serum albumin (HSA) was measured with enzyme linked immunosorbent assays (ELISAs).
RESULTS—None of the unexposed controls had a positive response to SPTs. The sensitivity (76.2% v 53.7%)...

Amine-Reactive Dyes for Dead Cell Discrimination in Fixed Samples

Perfetto, Stephen P.; Chattopadhyay, Pratip K.; Lamoreaux, Laurie; Nguyen, Richard; Ambrozak, David; Koup, Richard A.; Roederer, Mario
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/2010 EN
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Amine-reactive dyes, also known as LIVE/DEAD® fixable dead cell stains, are a class of viability dyes suitable for identifying dead cells in samples that will be fixed. These dyes cross the cell membranes of dead cells, and react with free amines in the cytoplasm. Live cells exclude these dyes because their cell membranes are intact, and free dye is washed away after staining. Notably, the reaction is irreversible; therefore, when cells are fixed and permeabilized (as with intracellular staining procedures), the bound dye remains associated with the dead cells (unlike other viability dyes). Since amine-reactive dyes are fluorescent when excited by lasers, dead cells can be identified by flow cytometry.

3D-QSPR Method of Computational Technique Applied on Red Reactive Dyes by Using CoMFA Strategy

Mahmood, Uzma; Rashid, Sitara; Ali, S. Ishrat; Parveen, Rasheeda; Zaheer-ul-Haq, ; Ambreen, Nida; Khan, Khalid Mohammed; Perveen, Shahnaz; Voelter, Wolfgang
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 05/12/2011 EN
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Cellulose fiber is a tremendous natural resource that has broad application in various productions including the textile industry. The dyes, which are commonly used for cellulose printing, are “reactive dyes” because of their high wet fastness and brilliant colors. The interaction of various dyes with the cellulose fiber depends upon the physiochemical properties that are governed by specific features of the dye molecule. The binding pattern of the reactive dye with cellulose fiber is called the ligand-receptor concept. In the current study, the three dimensional quantitative structure property relationship (3D-QSPR) technique was applied to understand the red reactive dyes interactions with the cellulose by the Comparative Molecular Field Analysis (CoMFA) method. This method was successfully utilized to predict a reliable model. The predicted model gives satisfactory statistical results and in the light of these, it was further analyzed. Additionally, the graphical outcomes (contour maps) help us to understand the modification pattern and to correlate the structural changes with respect to the absorptivity. Furthermore, the final selected model has potential to assist in understanding the charachteristics of the external test set. The study could be helpful to design new reactive dyes with better affinity and selectivity for the cellulose fiber.

Nucleophilic Addition of Reactive Dyes on Amidoximated Acrylic Fabrics

El-Shishtawy, Reda M.; El-Zawahry, Manal M.; Abdelghaffar, Fatma; Ahmed, Nahed S. E.
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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Seven reactive dyes judiciously selected based on chemical structures and fixation mechanisms were applied at 2% owf of shade on amidoximated acrylic fabrics. Amidoximated acrylic fabric has been obtained by a viable amidoximation process. The dyeability of these fabrics was evaluated with respect to the dye exhaustion, fixation, and colour strength under different conditions of temperature and dyeing time. Nucleophilic addition type reactive dyes show higher colour data compared to nucleophilic substitution ones. FTIR studies further implicate the binding of reactive dyes on these fabrics. A tentative mechanism is proposed to rationalize the high fixation yield obtained using nucleophilic addition type reactive dyes. Also, the levelling and fastness properties were evaluated for all dyes used. Excellent to good fastness and levelling properties were obtained for all samples irrespective of the dye used. The result of investigation offers a new method for a viable reactive dyeing of amidoximated acrylic fabrics.

Sistemas microemulsionados aplicados à remoção da cor de efluente têxtil

Beltrame, Leocádia Terezinha Cordeiro
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Química; Pesquisa e Desenvolvimento de Tecnologias Regionais Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Química; Pesquisa e Desenvolvimento de Tecnologias Regionais
Tipo: Tese de Doutorado Formato: application/pdf
POR
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Effluent color resulting from textile dyeing processes has been one of the biggest environmental problems faced by the textile industry. In particular, reactive dyes are highly resistant to conventional wastewater treatment methods. New technologies have been contemplated, some of which have been applied in industrial treatment plants, but color removal has not been efficiently attained. Since microemulsion systems provide good results in heavy metals and proteins extraction processes, their use in dyes extraction has been suggested and investigated. In this work, a real textile wastewater from an exhaustion dyebath has been treated, which contains the following reactive dyes: Procion Yellow H-E4R (CI Reactive Yellow 84), Procion Blue H-ERD (CI Reactive Blue 160) and Procion Red H-E3B (CI Reactive Red 120), in addition to auxiliary compounds normally found in dyeing processes with reactive dyes. The dyes Remazol Blue RR and Remazol Turquoise Blue G (Reactive Blue 21) have also been examined in view of the presence of heavy metals in these molecules. The microemulsion system comprised dodecyl ammonium chloride (as a cationic surfactant), water or wastewater as aqueous phase, kerosene as oil phase, and one of the following alcohols as cosurfactant: isoamyl alcohol...

Treatment of dyeing wastewater including reactive dyes (Reactive Red RB, Reactive Black B, Remazol Blue) and Methylene Blue by fungal biomass

Gül,Ülküye Dudu
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 EN
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The decolourisation potential of growing Rhizopus arrhizus fungal strain in liquid medium containing thiamine was investigated for the removal of anionic reactive dyes such as Reactive Red RB (RR), Reactive Black B (RBB) and Remazol Blue (RB) and a cationic basic dye Methylene Blue (MB). To determine the optimal pH value, pH 2 to 6 was examined. Fungal growth was not observed at pH 2. Maximum fungal decolourisation ocurred at pH 3 for anionic reactive dyes (RR, RBB, RB) and pH 6 for cationic MB dye. The fungal dye bioremoval was associated with the surface charge of the fungus due to electrostatic interactions. Growing R. arrhizus strain decolourised 100% of RB in 2 days, 100% of RBB in 3 days, 71.83% of RR in 8 days at pH 3 and 92.5% of MB in 8 days at pH 6 at 100 mg/ℓ dye concentration. Results indicate that growing Rhizopus arrhizus is an effective candidate for removal of different types of dyes from textile effluents.

The applicability of nanofiltration for the treatment and reuse of textile reactive dye effluent

Chollom,MN; Rathilal,S; Pillay,VL; Alfa,Dorcas
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 EN
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594.965%
The main aim of the study was to test the feasibility of using nanofiltration (NF) processes for the treatment of reactive dye-bath effluents from the textile industry, in order to recover the water and chemicals (salts) for reuse purposes. The study of the reusability of nanofiltered water for dyeing has been given little or no attention. About 30% of reactive dyes remain unfixed on fibres; the unfixed dyes are responsible for the colouration in effluents. Membrane processes were employed to treat reactive dye-bath effluents to recover the salts and water. Investigations were conducted firstly with ultrafiltration (UF) used as a pre-treatment for NF. Secondly, evaluations were performed for 2 types of NF membranes (SR90 and NF90), in terms of quality of permeate produced and fluxes achieved for 2 different samples of effluent. The effect of cleaning on membrane performance was assessed. A reusability test was carried out on both permeate samples for dyeing light and dark shade recipes. The use of UF as pre-treatment to NF resulted in rejection of colloidal substances > 90% and a 15% flux improvement. Permeate from NF90 had a conductivity of 76 µS/cm and total organic carbon (TOC) of 20 mg/ℓ, as compared to SR90 which had a conductivity of 8.3 mS/cm and a TOC of 58 mg/ℓ. Light shade from NF90 gave satisfactory results on dyeing...