Vat Dyestuffs Research Articles

Textile dyeing industry: environmental impacts and remediation.

Color is a major attraction component of any fabric regardless of how admirable its constitution. Industrial production and utilization of synthetic dyestuffs for textile dyeing have consequently become a gigantic industry today. Synthetic dyestuffs have introduced a broad range of colorfastness and bright hues. Nonetheless, their toxic character has become a reason of serious concern to the environment. Usage of synthetic dyestuffs has adverse impacts on all forms of life. Existence of naphthol, vat dyestuffs, nitrates, acetic acid, soaping chemicals, enzymatic substrates, chromium-based materials, and heavy metals as well as other dyeing auxiliaries, makes the textile dyeing water effluent extremely toxic. Other hazardous chemicals include formaldehyde-based color fixing auxiliaries, chlorine-based stain removers, hydrocarbon-based softeners, and other non-biodegradable dyeing auxiliaries. The colloidal material existing alongside commercial colorants and oily froth raises the turbidity resulting in bad appearance and unpleasant odor of water. Furthermore, such turbidity will block the diffusion of sunlight required for the process of photosynthesis which in turn is interfering with marine life. This effluent may also result in clogging the pores of the soil leading to loss of soil productivity. Therefore, it has been critical for innovations, environmentally friendly remediation technologies, and alternative eco-systems to be explored for textile dyeing industry. Different eco-systems have been explored such as biocolors, natural mordants, and supercritical carbon-dioxide assisted waterless dyeing. Herein, we explore the different types of dyeing processes, water consumption, pollution, treatment, and exploration of eco-systems in textile dyeing industry.

Development of colors with sustainability: a comparative study between dyeing of cotton with reactive and vat dyestuffs

This study compared reactive dyestuffs and vat dyestuffs in the dyeing of cotton. We investigated the possibility of reuse of the effluent generated, the ecological costs, and the colorfastness to water, rubbing, daylight, and perspiration. The experiments with vat dyestuffs showed slight advantage in terms of ecological costs, generating less molecules of carbon dioxide than the experiments conducted with reactive dyestuffs, lower consumption of energy, and greater possibility for reuse of treated effluent. In addition, vat dyestuffs exhibited decolorization efficiency above 99% and rates of total organic carbon removal over 90% in all cases, in addition to higher values in colorfastness properties.

Atmospheric plasma treatment of polypropylene fabric for improved dyeability with insoluble textile dyestuff

Polypropylene (PP) fabrics were activated by an atmospheric pressure, dielectric barrier discharge to optimize the effects of some discharge parameters on the dyeability of PP fabrics. Air and argon plasmas were used to modify the surfaces of the fabrics, and the effects on dyeability were investigated when the treated fabrics were dyed by leuco and pigment forms of vat dyestuffs. Surface properties of plasma-treated samples were characterized by Fourier transform infrared spectroscopy (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Vat-dyed samples showed a significant increase in color strength when PP fabrics were pretreated with atmospheric pressure plasmas of either argon or air.

Potentiostatic studies on indirect electrochemical reduction of vat dyes

Dispersed vat dyestuffs can be electrochemically reduced by indirect electrolysis using iron–triethanolamine complex as a reducing agent. The application and mechanism of indirect electrolysis as a reduction technique are described in detail in this paper. Electrochemically reduced vat dye is tested on a laboratory scale in dyeing experiments, and the results of different reduction conditions are discussed. The influence of the concentration of the complex-system on the build-up of colour depth, shade and fastness is discussed and compared with samples of the standard dyeing procedure using sodium dithionite as the reducing agent. The new process offers environmental benefits as well as prospects for improved process stability, because the state of reduction in the dye-bath can be readily monitored by measuring the reduction potential.

STUDY OF THE RESPONSE OF COTTON FABRIC STRUCTURE TO DYEING WITH A NATURAL DYE (HENNA) COMPARED TO REACTIVE AND VAT DYESTUFFS

STUDY OF THE RESPONSE OF COTTON FABRIC STRUCTURE TO DYEING WITH A NATURAL DYE (HENNA) COMPARED TO REACTIVE AND VAT DYESTUFFS

Separation of Anthracene from Crude Anthracene Using Gas Antisolvent Recrystallization

Abstract Pure anthracene is mostly used for conversion to anthraquinone, an intermediate for the synthesis of very powerful vat dyestuffs. A coal tar distillate, crude anthracene, which contains 30% anthracene, 25% phenanthrane, 15% carbazole, and other impurities, was used as the model mixture. In this study, 90% by weight purity anthracene was obtained using gas antisolvent (GAS) recrystallization. The GAS process induces the separation of solids by introducing an antisolvent, carbon dioxide (or the supercritical fluid), into acetone which was used as the liquid solvent. The dissolution of the compressed gas into the solute-laden solution selectively lowers the solubilities of solid solutes and salts them out. The results showed that high purity anthracene was obtained at a high feed concentration and high pressure conditions. The separation factor of anthracene versus phenanthrene is close to 30.07.

Cotton Protective Apparel for the Space Shuttle

All the materials for use either in a manned space flight or in a flight experiment, including materials of the spacecraft, crew provision, and equipment, must be evaluated and meet certain performance criteria as established during the Mercury, Gemini, Apollo, and Skylab programs. In addition to testing for the primary requirements of flame-resistance, odor, offgassing products, flash- and fire-point temperatures, cotton textile items were also considered as candidate space-shuttle, in-flight apparel on the basis of skin sensitivity, comfort, electrieal resistivity, colorfastness, and general protective features exhibited under certain conditions of flame and heat exposure. Chemically-treated flame-resistant cotton fabries that have been approved for space-shuttle apparel include a two-ply sateen (244 g/m2), a filling sateen (153 g/m2), and a two-ply, mercerized, single-knit jersey (187 g/m2). These fabrics are being used to fabricate the total flight ensemble from underwear to coverall and outer jacket. Fabrics for the outer garments were dyed to NASA-specified shades of blue with stable vat dyestuffs, compatible with the flame resistant treatment. These cotton fabrics were treated first with commerciat phosphonium salts and subsequently cured with gaseous ammonia. The process is more commonly referred to as the tetrakis(hydroxymethyl)phosphonium hydroxide/ammonia (THPOH/NH3) method. A second finishing application was required in order for the finished textile items to meet the slightly oxygen-enriched environment of the spacecraft crew bay area. The final finishing process comprised adding on diammonium phosphate (DAP)/urea, drying, curing (90 s @177°C), and afterwashing. DAP is a more efficient flame inhibitant than the phosphonium polymer, thus the combination treatment served to impart higher resistance to ignition and sustained combustion, as required by NASA test standards.

STUDIES ON A FEW FACTORS OF PRINTING PASTES FOR BLOTCH METHOD

On Blotch Method by machine printing specially among the printing methods using Vat dyestuffs, a few factors were measured in order to find the following: (1) Physical properties of printing pastes. (2) The influence of these properties on the result of printing, That is, on printing pastes for Blotch Method which uses all kinds of thickener, their viscosity, spinnability, sharpness, levelness and colour value, fixed value, fixed percentage etc. of the prints steamed in Flash Ager were measured.The results obtained are as follows:1) As printing pastes for Blotch Method, wheat starch, Sodium alginate and Schisa are suitable.2) Single thickener which excels from every point of view does not exist.3) As mixed printing pastes for Blotch method, mixture of Wheat starch and Sodium alginate are excellent.

Oxidising Agents and Vat-dyed Cotton

IN the course of an investigation into the action of oxidising agents upon cotton dyed with vat dyestuffe, we have obtained evidence of a simple relationship between the stable potential set up when a platinum electrode is dipped into a dilute solution of sodium hypochlorite, and the amount of chemical modification produced when this solution acts, under standard conditions, upon pure cotton cellulose dyed with the reduced or leuco form of certain vat dyestuffs. These results may prove of interest to those engaged in a study of the chemistry of cellulose and similar polymolecular compounds and also to those who are working on phenomena of oxygen transfer facilitated by a chemically labile substance.

Influence of certain Vat Dyestuffs on the Tendering of Cellulose when Exposed

Influence of certain Vat Dyestuffs on the Tendering of Cellulose when Exposed

The Action of Light on Cotton Dyed with Vat Dyestuffs

Journal of the Society of Dyers and ColouristsVolume 44, Issue 9 p. 268-274 The Action of Light on Cotton Dyed with Vat Dyestuffs F. Scholefield, F. ScholefieldSearch for more papers by this authorC. K. Patel, C. K. PatelSearch for more papers by this author F. Scholefield, F. ScholefieldSearch for more papers by this authorC. K. Patel, C. K. PatelSearch for more papers by this author First published: September 1928 https://doi.org/10.1111/j.1478-4408.1928.tb01514.xCitations: 12AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume44, Issue9September 1928Pages 268-274 RelatedInformation

The Reactions of the Vat Dyestuffs upon the Cotton Fibre.

The Reactions of the Vat Dyestuffs upon the Cotton Fibre.