Dyeing Auxiliaries Research Articles

Effect of dye auxiliaries on color and COD removal from simulated reactive dyebath effluent by electrocoagulation

In this paper, application of electrocoagulation using common electrode materials (aluminum and stainless steel) to a simulated reactive dyebath effluent was investigated. A mixture of dyes and auxiliary chemicals rather than a single dyestuff was employed to reflect actual reactive dyeing conditions. The experimental study focused on the effect of individual reactive dyebath components on color and COD removal rates and efficiencies by electrocoagulation. Electrocoagulation using stainless steel electrodes was found to be more effective particularly for color abatement. Na 2 CO 3 significantly reduced the process efficiency both in terms of color and COD removals. An adverse effect on COD removal efficiency was also observed for the sequestering agent. On the other hand, increasing the NaCl concentration not only enhanced color and COD removal efficiencies but also compensated the adverse effects of Na 2 CO 3 and sequestering agent on the electrocoagulation process. The dominant mechanism of color and COD removals from reactive dyebath effluent by electrocoagulation seemed to be coagulation and adsorption at pH values above 11.

Effect of dye auxiliaries on the kinetics of advanced oxidation UV/H2O2 of Acid Orange 7 (AO7)

AbstractBACKGROUND: The effect of four dye‐auxiliary chemicals, typically employed in acid dyeing, on the performance of UV/H2O2 decolouration of the model non‐biodegradable dye C.I. Acid Orange 7 (AO7) was investigated. The initial concentration of AO7 was 0.150 g L−1, while the concentration of the auxiliary compounds (NaCl, Na2SO4, Na2CO3 and CH3COOH) was varied in the range 1–10 g L−1.RESULTS: The negative influence of the presence of the dye‐auxiliary compounds studied on the decolouration rate of AO7 decreased in the following order: CH3COOH > Na2SO4 > NaCl > Na2CO3. Results were quantified in terms of the observed kinetic rate constant, kobs (s−1), of AO7 decolouration as a function of dye auxiliary chemical concentration. The decolouration rate of AO7 decreased as the concentration of dye‐auxiliary compound increased in the range 1–5 g L−1, while higher concentrations had a minor effect. Upon addition of 5 g L−1 of CH3COOH, NaCl and Na2SO4, the kinetic rate constant decreased by 39%, 30% and 12%, respectively.CONCLUSIONS: It was concluded that the presence of NaCl, Na2SO4 and above all of CH3COOH should be considered in the design of the treatment of real dye‐bath effluents by UV/H2O2. Copyright © 2008 Society of Chemical Industry

Preparation and surface activity of biodegradable polymeric surfactants II: Dyeing properties of biodegradable dextrin derivatives in cotton dyeing

AbstractThe biodegradability and dyeing properties of a series of dextrin‐derivative surfactants in direct‐dye cotton‐dyeing systems have been studied. It was found that these surfactants have good biodegradability, which is lacking in traditional dyeing auxiliaries. In dye‐surfactant systems, the degree of aggregation of direct dyes with surfactants was found to influence the rate of cotton dyeing. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2620–2624, 2007

Effects of Auxiliaries on Acid Dyeing of Shrink-Proofed Wool Fibers

The sorption behavior of an acid dye for shrink-proofed wool fibers, which were treated by means of three methods, Kroy, DCCA, and THPP (phosphorus compound) method, was investigated, to be compared with that of untreated fibers. The sorption isotherms for the wool fibers were determined and analyzed using dual sorption mechanism in order to calculate the sorption parameters, the number of binding sites for Langmuir type sorption, the intrinsic binding constant for Langmuir type sorption, and the partition coefficient. The number of binding sites for the wool fiber treated using Kroy method was lower than those for the other wool fibers in buffer solutions. Kroy treatment made the intrinsic binding constant lower in pH4 buffer solutions. Three cationic bolaform electrolytes were used as dyeing auxiliaries for the acid dyeing of the shrink-proofed wool fibers. Their effects were dependent on the structure of the bolaform electrolytes. In the case of the bolaform electrolyte containing hydroxyl and amino groups, the number of binding sites was increased, while the degree of the increase was different between two substituents. Furthermore, the addition of the bolaform electrolytes having hydroxyl groups made the partition coefficients higher. Such effects changed with different shrink-proofing methods.

Acid dyebath effluent pretreatment using Fenton's reagent: Process optimization, reaction kinetics and effects on acute toxicity

Fenton's reagent (Fe 2+/H 2O 2) is known as one of the most effective and most often employed advanced oxidation process (AOPs) for the treatment of textile dyes and dyehouse effluent. In the present study, a synthetic acid dyebath effluent (SADB) bearing two azo and one anthraquinone dye together with two dye auxiliaries was subjected to pretreatment with Fenton's reagent. Firstly, initial Fe 2+ and H 2O 2 concentrations as well as pH were optimized to achieve highest COD and color removals during Fenton's treatment of SADB. In the second stage of the experimental work, kinetic studies were conducted to elucidate the effect of operating temperature (20 °C < T < 60 °C) on COD, color abatement and H 2O 2 consumption kinetics. Obtained results indicated that 30% COD and practically complete color removal (99%) could be achieved at T = 50 °C. The kinetic studies revealed that a strong correlation existed between COD removal and H 2O 2 utilization rates. In the final part of the study, the acute toxicity of raw (untreated) and pretreated SADB on heterotrophic biomass was investigated employing a modified (COD-balanced), activated sludge inhibition test. The toxicity experiments demonstrated that the inhibitory effect of SADB towards sewage sludge could be completely eliminated when the effluent was pretreated with Fenton's reagent.

Elucidation of Microenvironments in Fiber and Polymer Matrices and Development of Novel Dyeing Auxiliaries for Fundamental Study on Supramolecular Dyeing and Finishing

Elucidation of Microenvironments in Fiber and Polymer Matrices and Development of Novel Dyeing Auxiliaries for Fundamental Study on Supramolecular Dyeing and Finishing

Effect of common reactive dye auxiliaries on the ozonation of dyehouse effluents containing vinylsulphone and aminochlorotriazine dyes

Ozonation of the commercially important reactive dyes Procion yellow HE4R (Reactive Yellow 84) and Remazol Black SB (Reactive Black 5) in actual dye rinse waters and simulated exhausted dye bath liquors has been studied. The effect of common dye auxiliaries (NaCl and Na 2CO 3) as well as the initial dye concentration on advanced oxidation kinetics was investigated. Decolourization was complete within a few minutes of ozonation in all cases whereas UV 254 (absorbance at 254 nm wavelength), COD and TOC removals required higher ozone doses. It was found that NaCl did not affect the ozonation process at the present reaction conditions, whereas the addition of Na 2CO 3 resulted in a significant inhibition in the abatement of all selected process parameters except decolourization. Increasing the initial dye concentration had an even more negative effect on decolourization, oxidation and mineralization kinetics. A simple kinetic model describing the effect of inhibitor concentrations on COD and/or colour removal rate constants has been proposed.

Enzymatic Decolorization of Textile Dyeing Effluents

Commercial azo, triarylmethane, antraquinonic, and indigoid textile dyes are efficiently decolorized with enzyme preparations from Pleurotus ostreatus, Schizophyllum commune, Neurospora crassa, Polyporus sp., Sclerotium rolfsii, Trametes villosa, and Mycelioph tora thermophila. The nature of substituents on the dyes' benzene rings influences enzyme activity, and hydroxyl and amino groups enhance decolorization. The presence of lignin peroxidase and/or manganese peroxidase in addition to laccase ( P. ostreatus, S. commune, S. rolfsii, N. crassa) increases decolorization by up to 25%. The effect of textile dyeing auxiliaries depends on the individual enzymes. Polyporus sp. and T. villosa are inhibited up to 20% by copper and iron chelating agents and anionic detergents, while the S. commune enzymes lose up to 70% of their activity.

Preparation and properties of novel low‐foaming dyeing auxiliaries. Part 2: Preparation and dyeing properties of anionic derivatives of polyoxyethylenated stearylamine

A novel series of anionic derivatives with low‐foaming properties were prepared by the reaction of polyoxyethylenated stearylamine and maleic anhydride. The structure of these surfactants was confirmed by infra‐red, nuclear magnetic resonance and elemental analysis. The surfactants were found to display low‐foaming properties and exhibit good surface‐active properties. The degree of aggregation of direct dyes in dye‐surfactant systems was found to influence the rate of cotton dyeing.

Preparation and properties of novel low‐foaming dyeing auxiliaries. Part 1 — Preparation and properties of ethoxylated hydroxysulphobetaines in nylon dyeing

A novel series of low‐foaming ethoxylated hydroxysulphobetaines has been prepared by the reaction of polyoxyethylenated stearylamine and sultone, and their structural features confirmed by infra‐red, nuclear magnetic resonance and elemental analysis. These compounds have good surface activity properties, including surface tension and wetting power. Complexes formed between them and acid dyes have greater solubility than the dye alone, decreasing the dye's affinity for nylon fibres, lowering the rate of dyeing and making them suitable for use as low‐foaming levelling agents.

Properties of Amphiphilic Calix(4)resorcinarenes Having Tetraalkyl Chains as Dyeing Auxiliaries.

Phosphate esters of calix_??_4_??_resorcinarenes having four alkyl chains (_??_4_??_Ar-Rn (P)) were prepared and examined as auxiliaries for dyeing of nylon 6 fiber with a disperse dye (KPLR). The dyeing with_??_4_??_Ar-Rn (P) was effective and the dye uptake was 40% more than that with a commercially available disperse agent (Disp-TL). The dyeing at 80°C and 95°C gave 10% and 25% higher dyeability respectively, as compared with the dye uptake using phosphate esters of monododecylresorcinol (M-R12 (P)). The maximal dye uptakes were obtained with 1-2g/dm3 of_??_4_??_Ar-Rn (P), and with 12g/dm3 of Disp-TL. respectively. The effect of_??_4_??_Ar-Rn (P) on the level dyeing was confirmed by the observation of the cross section of dyed fiber.

Dye Auxiliaries in the Application of Disperse Dyes to Man‐made Fibres

The different types of auxiliaries used in the dyeing of man‐made fibres with disperse dyes are considered. The requirements of dispersing agents are discussed in relation to the chemical nature and properties of the agent (anionic, cationic or non‐ionic). The uses and properties of carriers are discussed, and, in particular, the carrier dyeing of fibre blends is described. A thorough understanding of the properties of auxiliaries enables the dyer to obtain the best results.