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Color Removal (color + removal)
Selected AbstractsUse of microemulsions for removal of color and dyes from textile wastewaterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2004Tereza Neuma de Castro Dantas Abstract One of the major environmental problems in the textile dyeing industry is the removal of color from effluents. The present study deals with color removal from effluents using microemulsions. The wastewater used in this study was the reactive exhausted dye liquor from a dyeing house containing 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). Color removal was determined by CIEL*a*b* (CIELAB) color space, CIEL*a*b* color difference, ,E*ab, and absorbance. Color removal greater than 95% was achieved, attaining values lower than the consent requirements established by the Environmental Agency. It was observed that pH is an important parameter in color removal and effluent pH correction from 10.44 to 9 before extraction improved results. The results obtained were modeled using the Scheffé net method and evaluated through the construction of isoresponse diagrams by correlation graphics between experimental values and those obtained through use of model equations, providing an experimental error of less than 2%. The optimized method very efficiently removed all dyes contained in the effluent. The same microemulsion phase recovered after the extraction process can be used at least a further 14 times and all the extractions gave good color removal. Copyright © 2004 Society of Chemical Industry [source] Decolorization of simulated textile dye baths by crude laccases from Trametes hirsuta and Cerrena unicolorENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2010Ulla Moilanen Abstract In this study crude laccases from the white-rot fungi Cerrena unicolor and Trametes hirsuta were tested for their ability to decolorize simulated textile dye baths. The dyes used were Remazol Brilliant Blue R (RBBR) (100,mg/L), Congo Red (12.5,mg/L), Lanaset Grey (75,mg/L) and Poly R-478 (50,mg/L). The effect of redox mediators on dye decolorization by laccases was also assessed. C. unicolor laccase was able to decolorize all the dyes tested. It was especially effective towards Congo Red and RBBR with 91 and 80% of color removal in 19.5,h despite the fact that simulated textile dye baths were used. Also Poly R-478 and Lanaset Grey were partially decolorized (69 and 48%, respectively). C. unicolor laccase did not need any mediators for removing the dyes. However, T. hirsuta laccase was only able to decolorize simulated Congo Red and RBBR dye baths (91 and 45%, respectively) in 19.5,h without mediators. When using mediators the decolorization capability was enhanced substantially, e.g. Poly R-478 was decolorized by 78% in 25.5,h. On the whole, both laccases showed potential to be used in industrial applications. [source] Flocculated decolorization of vinylsulfone reactive dye solutions with a ,-cyclodextrin-based copolymerJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2010Xiuzhi Tian Abstract A ,-cyclodextrin (,-CD)-based copolymer (,-CD,maleic anhydride,N -trimethylaminoethylmethacrylate chloride) with good thermal stability was designed and synthesized for flocculated decolorization of Reactive Brilliant Blue KN-R solutions. Jar tests indicated that with the optimal stirring mode as 120 rpm for 5 min and then 40 rpm for 5 min with a flocculant-to-dye ratio of 2 : 5 (w/w), a pH of 8,10, and a temperature of 20°C, the maximum color removal reached. It is reported first in this article that, in addition to the polymer bridge and charge neutralization, the covalent bond of the reactive dye to the target flocculant molecules, which had a similar chemical structure to that of cellulose, contributed to the mechanism of flocculated decolorization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Treatment of paper and pulp wastewater and removal of odorous compounds by a Fenton-like process at the pilot scaleJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2006José L Tambosi Abstract A Fenton-like process, involving oxidation and coagulation, was evaluated for the removal of odorous compounds and treatment of a pulp and paper wastewater. The main parameters that govern the complex reactive system [pH and Fe(III) and hydrogen peroxide concentrations] were studied. Concentrations of Fe(III) between 100 and 1000 mg L,1 and of H2O2 between 0 and 2000 mg L,1 were chosen. The main mechanism for color removal was coagulation. The maximum COD, color and aromatic compound removals were 75, 98 and 95%, respectively, under optimal operating conditions ([Fe(III)] = 400 mg L,1; [H2O2] = 500,1000 mg L,1; pH = 2.5; followed by coagulation at pH 5.0). The biodegradability of the wastewater treated increased from 0.4 to 0.7 under optimal conditions and no residual hydrogen peroxide was found after treatment. However, partially or non-oxidized compounds present in the treated wastewater presented higher acute toxicity to Artemia salina than the untreated wastewater. Based on the optimum conditions, pilot-scale experiments were conducted and revealed a high efficiency in relation to the mineralization of organic compounds. Terpenes [(1S)-,-pinene, ,-pinene, (1R)-,-pinene and limonene] were identified in the wastewater and were completely eliminated by the Fenton-like treatment. Copyright © 2006 Society of Chemical Industry [source] Influence of cosurfactant in microemulsion systems for color removal from textile wastewaterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2005Leocadia Terezinha Cordeiro Beltrame Abstract Microemulsion systems have proved very efficient in color removal from textile wastewater using n -butyl alcohol as cosurfactant. The cosurfactant has a very important role in microemulsified systems, as it is responsible for their stability, mainly in systems formed by ionic surfactants. Although very efficient, n -butyl alcohol is partially soluble in water, which would permit its passage to the effluent. In this work, isoamyl and octyl alcohols, due to their lower solubility in water, were used as cosurfactants to evaluate their influence in color removal. The colorimetry system used was the CIE L*a*b* (CIELAB) color space and CIE L*a*b* color difference (,E*ab). The wastewater used in this study was the reactive exhausted dye liquor from a dye house (first discharge) containing 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). The obtained results were modeled using an experimental planning (the Scheffé net) and evaluated through isoresponse diagrams by correlation graphs between experimental values and those obtained by the models with an error lower than 4%. All the optimized systems were very efficient and more than 94% of the dyes contained in the effluent were removed. The microemulsion load capacity was determined using a synthetic solution containing, the same dyes present in the reactive exhausted dyebath, but 200 times concentrated, and the dyes extraction was more than 99.6%. By comparing n -butyl, isoamyl and octyl alcohols, it was observed that the system using isoamyl alcohol presented slightly better color removal and much higher load capacity than the n -butyl and octyl alcohols. Copyright © 2004 Society of Chemical Industry [source] Use of microemulsions for removal of color and dyes from textile wastewaterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2004Tereza Neuma de Castro Dantas Abstract One of the major environmental problems in the textile dyeing industry is the removal of color from effluents. The present study deals with color removal from effluents using microemulsions. The wastewater used in this study was the reactive exhausted dye liquor from a dyeing house containing 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). Color removal was determined by CIEL*a*b* (CIELAB) color space, CIEL*a*b* color difference, ,E*ab, and absorbance. Color removal greater than 95% was achieved, attaining values lower than the consent requirements established by the Environmental Agency. It was observed that pH is an important parameter in color removal and effluent pH correction from 10.44 to 9 before extraction improved results. The results obtained were modeled using the Scheffé net method and evaluated through the construction of isoresponse diagrams by correlation graphics between experimental values and those obtained through use of model equations, providing an experimental error of less than 2%. The optimized method very efficiently removed all dyes contained in the effluent. The same microemulsion phase recovered after the extraction process can be used at least a further 14 times and all the extractions gave good color removal. Copyright © 2004 Society of Chemical Industry [source] Size and Structure Characterization of Dye Flocs during Coagulation of Reactive Black 5 DyePARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 2 2006Marta Janeczko Abstract This paper deals with results from laboratory scale experiments with model dye effluents comprising of the commercially used textile diazo dye, CI "Reactive Black 5", coagulated with ZETAG type primary coagulants. Size and structure analysis of flocs in coagulated dye sludge was undertaken in order to evaluate their separation abilities. The particle size distribution was estimated by use of a Galai CIS-100 particle counting system working on a time-of-transition principle, while their fractal dimension was obtained from laser scattering instrument in LALS mode. An image analysis of the flocculated dye-sludge has also been carried out. In parallel to the flocs characterization, the measurement of surface charge density of coagulated dye sludge was performed with the aim of linking surface charge data with the floc characteristics, and on this basis, to outline the predominant mechanism of color removal. It was found that flocs produced at optimal dosage are characterized by large sizes and a high value of fractal dimension, which is manifested in a very good level of color removal by sedimentation. The evident correlation between the surface charge density progression of coagulated dye flocs and color removal, suggests adsorption and charge neutralization as the predominant mechanism of dye destabilization. [source] Removal of organic dyes in the hybrid photocatalysis/nanofiltration systemASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009Joanna Grzechulska-Damszel Abstract The removal of azo dyes acid red 18 (AR18), direct green 99 (DG99) and acid yellow 36 (AY36) in hybrid photocatalysis/nanofiltration (NF) system was investigated. The photocatalytic reactions were conducted in the flow reactor with immobilized photocatalyst bed. A commercially available titanium dioxide (Aeroxide® P25, Degussa, Germany) was used as a photocatalyst. The solution after the photocatalytic reaction was applied as feed for NF process. The changes of various parameters, including concentration of dyes, pH and conductivity of the solution, total organic carbon (TOC) and total dissolved solids (TDS) content were analyzed during the process. It was found that azo dyes AR18, DG99 and AY36 solutions could be successfully decolorized in the quartz labyrinth flow reactor with immobilized photocatalyst bed. The rate of color removal can range as follows: AR18 > DG99 > AY36. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Color and Toxicity Removal following Tyrosinase-Catalyzed Oxidation of PhenolsBIOTECHNOLOGY PROGRESS, Issue 4 2000Keisuke Ikehata The products of phenol oxidation catalyzed by mushroom tyrosinase (polyphenol oxidase, EC 1.14.18.1) were assessed in terms of their residual color and toxicity. The addition of aluminum sulfate had little effect on the removal of colored products from phenol solutions treated with tyrosinase. Although chitosan was used successfully to remove the color when added before the reaction initiation or after the reaction completion, the required dose of chitosan was lower when it was added after the reaction. In this case, the minimum doses of chitosan required to achieve 90% color removal were proportional to the logarithm of the initial concentration of phenol. The color removal induced by chitosan addition appeared to be the result of chemical interaction followed by a coagulation mechanism. All treated solutions of phenol and chlorophenols, except 2,4-dichlorophenol, had substantially lower toxicities than their corresponding initial toxicities, as measured using the Microtox assay. Chitosan addition significantly enhanced the reduction in toxicity. The toxicities of the phenol solutions treated with tyrosinase were markedly lower than previously reported toxicities of solutions treated with peroxidase enzymes. [source] | ||||||||||||||||