Dye Bath Research Articles

Valorization of natural dye extracted from date palm pits (Phoenix dactylifera) for dyeing of cotton fabric. Part 2: Optimization of dyeing process and improvement of colorfastness with biological mordants

This paper investigates the feasibility of dyeing cotton fibers with solution extracted from date pits which are abundant vegetal material. The extraction step and its optimization were conducted in the first part of this paper. This second part studies the influence of the main dyeing conditions on the color yield K/S and the CIELab coordinates. The studied parameters are pH of the dye bath, temperature and duration of dyeing. Experiments were carried out using Box-Behnken experimental design to be able to analyze the main effects of each parameter, to detect interactions between these parameters and to deduce optimum conditions for dyeing process. The fastness properties of dyed samples were also evaluated. Obtained results indicate interesting sweat, washing and rubbing fastness in the range of 4–5. Three metallic mordants (Alun, ZnSO4 and CuSO4) and three biological mordants (gall nuts, chlorophyll (a) and green almond shell) were used to improve the degree of absorption as well as the color fastness of cotton fabrics dyed with aqueous extract from date pits. The obtained results showed high improvement of fastness (sweat, friction, washing and light fastness) for biological mordants than the metallic ones.

Effect of chemical modification with 4-vinylpyridine on dyeing of cotton fabric with reactive dyestuff

Cotton fabrics were pre-treated with 4-vinylpyridine before dyeing to increase dye uptake. Various treatments for the application of monomers to fabrics were tried in different combinations and after dyeing the best result was obtained with alkali impregnation and monomer exhaustion. After decisions had been made on the processes to be applied before dyeing, different amounts of monomer, dyestuff and salt were used in reactive dyeing baths at different pHs. The results were evaluated in terms of color coordinates, color strength, FT-IR and fastness to washing, rubbing and perspiration. The best results were obtained with 3 ml of 4-vinylpyridine dissolved in 10 ml of alcohol, in the presence of 25 g L−1 of salt and in neutral medium at 5% dyestuff concentration. Color strength from this dyeing process was higher than from the conventional dyeing at the same dyestuff concentration. FT-IR analysis demonstrated the presence of monomer on the surface of the fabric. Fastness values showed that this method could be used as an alternative to the conventional method.

Preparation of a Low Reducing Effect Sulfonated Alkali Lignin and Application as Dye Dispersant.

A novel grafting hydroxypropyl sulfonated and blocking condensed lignin (GSBAL) dye dispersant was prepared based on alkali lignin (AL) by sulfonation and etherification reactions. The significant increase in the sulfonic group content and the molecular weight endow GSBAL with excellent dispersity and stability at high temperatures. More importantly, the unfavorable property of the reducing effect of AL was largely reduced since over 80% of the phenolic hydroxyl groups were blocked. The functional azo groups in the dye could be mostly retained. The reducing rate of dye with GSBAL was decreased to 6.54% (25 °C), much lower than 18.62% for sulfomethylated alkali lignin (SAL) and 15.73% for sodium lignosulfonate (NaLS). The dispersity and exhaustion of the dye bath with GSBAL dispersant was significantly improved compared with that of a dye bath with SAL and NaLS.

Experimental Study on Antimicrobial Activity of Silk Fabric Treated with Natural Dye Extract from Neem (Azadirachta indica) Leaves

In the present study, a novel eco-friendly production of silk fabrics dyed with different natural dye bath concentrations (40, 80, 120, 160, 200 and 240 g/l) extracted from neem (Azadirachta indica) leaves was developed. The surface morphology of the fabrics was examined by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy to characterize the chemical structure of the fabrics. The SEM images of the undyed fabric show that the fabric was tightly woven with little porosity between the fibres with dozens of silk threads in orthogonal directions. By increasing the neem concentration, a scale of fine particles grew on the surface of the silk fabrics with little macroscopical defects was demonstrated. The fiber diameters and tightness between filaments were significantly increased. The FTIR displayed that, neem dye does not change the characteristic peaks of the silk fabrics. Also, the evaluation of the antimicrobial activity of the undyed and neem dyed silk fabrics was monitored for Gram positive and Gram negative bacteria in addition to yeasts and fungi by using the agar diffusion method. The comparison between the different dye bath concentrations was based on the inhibition zones obtained after incubation. The antimicrobial activity in leaf extract of neem was estimated in Staphylococcus aureus, Bacillus subtilis and Lactobacillus cereus (Gram positive bacteria); Escherichia coli (Gram negative bacteria); Candida albicans and Candida tropicalis (yeasts); and Aspergillus niger and Fusarium solani (fungi). The results emphasized that, the highest neem dye bath concentration (240 g/l) was found to display good inhibitory effect against the Gram positive and reasonable activity against the Gram negative bacteria. Furthermore, the different dye bath concentrations possess no activities against yeast and fungi. In conclusion, the data reveal that the increase of neem dye concentration does not damage the silk fabric; however, it improves its antimicrobial activity by incorporating with antimicrobial agent. The current study highlighted that using neem leaves had beneficial effect in controlling the pathogenic microbial organisms.

Modification of Woolen Fabric with Plasma for a Sustainable Production

In this study, the effects of corona plasma process on the dyeability and certain physical properties of woolen fabric were investigated. For this purpose, acid and 1.2 metal complex dyes, which are the most applicable dyes in the wool market were used. The patterns were examined to assess their dyeability, wettability, pilling resistance, alkali solubility, and strength values. The surface morphology and chemical structures were tested by X-ray photoelectron spectroscopy and alkali solubility analyses and also scanned by electron microscopy. Hydrophility indexes of the dyes that were used were determined. With the results of the experiments, their hydrophobic index is of vital importance, which is a factor for plasma efficiency on color depth. By using plasma treatment on woolen fabric, it is achievable to get a product with high hydrophility and pilling resistance values, dyeability, and less burdened dyeing bath.

Antibacterial dyeing of silk with prodigiosins suspention produced by liquid fermentation

As a kind of natural dye, microbial pigments are attracting more and more attention for their application in textile dyeing. In this study, prodigiosins suspension produced by fermentation of Serratia marcescens was utilized as a novel kind of cleaner dye liquor for silk fabric dyeing. The average particle size of pigment particles was 217.1 nm and the prodigiosins concentration was determined to be 69.38 mg/L. Effects of technical parameters including dyeing temperature, dyeing time and dye liquor pH on dyeing effect and antibacterial capability of dyed fabrics were explored. The results indicated that when the dyeing temperature was 80 °C with a holding time of 30 min, dyed silk under dye bath pH 2.1 possessed high color strength, good color fastness and outstanding bacteriostatic rate of above 93.0% against Staphylococcus aureus. In addition, in vitro cytocompatibility test indicated that dyed silk fabric had no potential cytotoxicity to L929 cells. This study provided an innovative clean approach of dyeing silk with prodigiosins and endowed the fabric with antibacterial activity, simultaneously.

English

The evaluation and comparison of the staining effect of pomegranate (Punica granatum) flower extract (dye solution) on histological sections of rat testis and ovary provides a simple, quick technique for the visualisation of both cells. In the developed procedure, this work shows the staining effect of P. granatum flower extract used at different pH of dye bath and temperatures on the histological sections of rat testis and ovary. A 20% stock solution of P. granatum flower extract was prepared by dissolving 20 g of the dye in 100 mL ethanol at room temperature for several hours. After 24 h, the deep-red coloured solution was filtered (0.45 µm filter) to remove any undissolved dye. This stock solution was stored at room temperature and each day a 5 mL sample was taken and adjusted to different pH with dilute ammonia (NH3) using pH meter. Best staining effects conditions were obtained by testing the different pH of dye (1-2, 4-5) and temperature. The testis and ovary are stained in different colors; lamina propria section and spermatogonia cells of testis were more purple than the same sections of ovary at room temperature and pH of 1-2 dye bath. Therefore, the developed method has been applied successfully for the visualization of rat testis and not the ovarian tissue. Key words: Histological section, ovarian, pomegranate, Punica granatum, testis.

Usage of Tagetes and Tanacetum as Dye Plants for Natural and Artificial Fibers

Abstract This study is presenting results from an experiment with two well-known dye plants and their interaction with different types of textile fibres. Briefly, fresh and dry inflorescences of Tagetes patula and dry inflorescences of Tanacetum vulgare were used for the preparation of a dyeing bath. Then, different samples of cloth (made from natural plant fibres (wool), artificial fibres (sloter and ortalion), both artificial and plant fibres (canvas) and natural animal fibres (wool)) were immersed into the hot dyeing baths. Results showed that both chosen plant species are suitable for textile dyeing, but they differ in colour density.

Treatment of synthetic dye baths by Fenton processes: evaluation of their environmental footprint through life cycle assessment.

Inorganic and organic constituents present in textile effluents have a noticeable effect on the performance of Fenton processes. However, studies have been focused on simple wastewater matrices that do not offer enough information to stakeholders to evaluate their real potential in large-scale facilities. Chemical auxiliaries, commonly present in textile wastewaters (NaCl = 30g/L, Na2CO3 = 5g/L, and CH3COONa = 1g/L), affect both the economic and environmental performance of the process because they increase the treatment time (from 0.5 to 24h) and the consumption of H2SO4 (657%) and NaOH (148%) during conditioning steps. The life cycle assessment (LCA) performed with the IPCC-2013 method revealed that dyeing auxiliaries increase from 1.06 to 3.73 (252%) the emissions of carbon dioxide equivalent (CO2-Eqv/m3). Electricity consumption can be considered an environmental hotspot because it represents 60% of the carbon footprint of the Fenton process. Also, the presence of auxiliaries is critical for the process because it results in the increase of the relative impact (between 50 and 80%) in all environmental categories considered by the ReCiPe-2008 method. Chemical auxiliaries increased the costs of the treatment process in 178% (US$2.22/m3) due to the higher energy consumption and the additional reagent requirements. It is worthwhile mentioning that the technical simplicity of the Fenton process and its low economic and environmental costs turn this process into an attractive alternative for the treatment of textile effluents in emerging economies.

Enzymatic decolorization of reactive dyeing baths

Enzymatic decolorization of reactive dyeing baths

Studies on Dyeing Parameters of Colourants Extracted from Camellia sinensis

Wool and silk fibres have been effectively dyed with an aqueous extract of C. sinensis from an acidic dye bath (pH ~ 4.0). Methanol extract of the dye has been used for measuring different kinetic and thermodynamic parameters. The results indicate that the dye has an affinity for wool and silk. The standard affinity value of C. sinensis for wool fibre is greater than that for the silk fibre and it increases with the increase in temperature. Rate of dyeing for wool is lower as compared to that of silk. Studies on adsorption isotherm indicate that this dye is adsorbed on protein fibres chiefly following Langmuir adsorption mechanism.

A test battery for assessing the ecotoxic effects of textile dyes

The textile dyeing industry is one of the main sectors contributing to environmental pollution, due to the generation of large amounts of wastewater loaded with dyes (ca. 2–50% of the initial amount of dyes used in the dye baths is lost), causing severe impacts on human health and the environment. In this context, an ecotoxicity testing battery was used to assess the acute toxicity and genotoxicity of the textile dyes Direct Black 38 (DB38; azo dye) and Reactive Blue 15 (RB15; copper phthalocyanine dye) on different trophic levels. Thus these dyes were tested using the following assays: Filter paper contact test with earthworms (Eisenia foetida); seed germination and root elongation toxicity test (Cucumis sativus, Lactuca sativa and Lycopersicon esculentum); acute immobilization test (Daphnia magna and Artemia salina); and the Comet assay with the rainbow trout gonad-2 cell fish line (RTG-2) and D. magna. Neither phytotoxicity nor significant effects on the survival of E. foetida were observed after exposure to DB38 and RB15. Both dyes were classified as relatively non-toxic to D. magna (LC50 > 100 mg/L), but DB38 was moderately toxic to A. salina with a LC50 of 20.7 mg/L. DB38 and RB15 induced significant effects on the DNA of D. magna but only DB38 caused direct (alkaline comet assay) and oxidative (hOGG1-modified alkaline comet assay) damage to RTG-2 cells in hormetic responses. Therefore, the present results emphasize that a test battery approach of bioassays representing multiple trophic levels is fundamental in predicting the toxicity of textile dyes, aside from providing the information required to define their safe levels for living organisms in the environment.

The Versatile SALSAC Approach to Heteroleptic Copper(I) Dye Assembly in Dye-Sensitized Solar Cells

Surface-bound heteroleptic copper(I) dyes [Cu(Lanchor)(Lancillary)]+ are assembled using the “surfaces-as-ligands, surfaces as complexes” (SALSAC) approach by three different procedures. The anchoring and ancillary ligands chosen are ((6,6′-dimethyl-[2,2′-bipyridine]-4,4′-diyl)-bis(4,1-phenylene))bis(phosphonic acid) (3) and 4,4′-bis(4-iodophenyl)-6,6′-diphenyl-2,2′-bipyridine (4), respectively. In the first SALSAC procedure, the FTO/TiO2 electrode is functionalized with 3 in the first dye bath, and then undergoes ligand exchange with the homoleptic complex [Cu(4)2][PF6] to give surface-bound [Cu(3)(4)]+. In the second method, the FTO/TiO2 electrode functionalized with 3 is immersed in a solution containing a 1:1 mixture of [Cu(MeCN)4][PF6] and 4 to give surface-anchored [Cu(3)(4)]+. In the third procedure, the anchor 3, copper(I) ion and ancillary ligand 4 are introduced in a sequential manner. The performances of the DSSCs show a dependence on the dye assembly procedure. The sequential method leads to the best-performing DSSCs with the highest values of JSC (7.85 and 7.73 mA cm−2 for fully masked cells) and overall efficiencies (η = 2.81 and 2.71%, representing 41.1 and 39.6% relative to an N719 reference DSSC). Use of the 1:1 mixture of [Cu(MeCN)4][PF6] and 4 yields DSSCs with higher VOC values but lower JSC values compared to those assembled using the sequential approach; values of η are 2.27 and 2.29% versus 6.84% for the N719 reference DSSC. The ligand exchange procedure leads to DSSCs that perform relatively poorly. The investigation demonstrates the versatile and powerful nature of SALSAC in preparing dyes for copper-based DSSCs, allowing the photoconversion efficiency of dye to be optimized for a given dye. The SALSAC strategy provides alternative hierarchical strategies where the isolation of the homoleptic [Cu(Lancillary)2]+ is difficult or time-consuming; stepwise strategies are more atom-economic than ligand exchange involving the homoleptic [Cu(Lancillary)2]+.

Application of phenolic compounds as natural dye extracted from date-pits: dyeing studies of modified acrylic fibres

This research work involves the dyeing of acrylic fabric with natural dye extracted from date pits powders using Soxhlet extraction process. The effect of dye bath pH, salt concentration, dyeing time and temperature were studied. The optimal dyeing conditions where pH 4, 0 g/L salt, 60 min, and 80 °C. The COD and the BOD5 of the residual dye bath were measured and it was shown from the registered values that the residual dye bath presents an acceptable rate of organic discharge.

Sustainable Dyeing of Microwave Treated Polyester Fabric using Disperse Yellow 211 Dye

The aim of current work is to evaluate the dyeing performance of newly introduced disperse dye to improve its dyeing behavior onto polyester fabric using microwave radiation. Microwave heating has promisingly improved the disperse dyeing of polyester fabrics. Disperse Yellow 211 (DY 211) has been used to dye the polyester fabric under the influence of microwave treatment. Both the fabric and dye solution, were treated with the microwaves for 1- 6 min. Different dyeing parameters such as temperature, time, dispersant and dye bath volume were also optimized and ISO standard methods for colorfastness were employed to rate the influence of microwave and ultraviolet treatment on disperse dyeing. It is found that microwave treated polyester (RP, 6 min), has given good color strength and darker shades upon dyeing at 90°C for 40 min. in the presence of 2 g/100ml of dispersant using 70 mL of irradiated dye solution (RS, 6 min) of pH 8. Similarly using dye bath of pH 11, microwave treated polyester (RP, 6 min.) has given good color strength and darker shades upon dyeing at 70°C for 35 min.in the presence of 1 g/100ml of dispersant. using 50 mL of irradiated dye solution (RS). ISO standards for fastness to light, washing and rubbing revealed that good to excellent ratings have been obtained from different shades dyed at optimal condition. It is inferred that Microwave treatment has not only reduced the dyeing conditions but also improved the color characteristics of dyed polyester fabric.

Electrochemical degradation of textile dyes in a flow reactor: effect of operating conditions and dyes chemical structure

In this study, electrochemical oxidation of five azo dyestuffs (Yellow D-5GN, Red D-B8, Ruby F-2B, Blue D-5RN, Black DN), that are widely used in the textile industry, was investigated in a flow reactor. BDD electrode with a high boron doping level (C/B = 10 000) was prepared and used. Two configurations of reactor were considered, i.e., one with the undivided cell, and the other with the cell divided by anodic and cathodic compartments. The effect of current density and the initial pH of the solution on the dyestuff degradation process was investigated. As expected, higher degradation rate was found for higher current density, while the effect of pH was marginal. Next, electrochemical oxidation of azo dyestuffs with different chemical structures was investigated. Based on the cyclic voltammetry measurements, the correlation between the dyestuff removal rate and the oxidation potential value of dyestuff was found. These results suggest that the direct oxidation of dyestuffs at the highly doped BDD anode plays a significant role in the electrochemical oxidation. Finally, the electrochemical removal of dyestuffs was carried out in two types of dyeing baths. The dyeing bath composition has a significant effect on the degradation efficiency. Chlorides in F-type dyeing bath accelerated electrochemical removal due to effective generation of Cl2/HOCl at the highly B-doped BDD anode. In contrast, OH− inhibited the D-type dyestuff removal from dyeing bath, because they acted as scavengers of ·OH radicals. Highly B-doped BDD anode is promising material to F-type dyestuff treatment in industrial wastewater.

Influence of dielectric barrier discharge treatment on mechanical and dyeing properties of wool

Physical and chemical properties of wool surface significantly affect the absorbency, rate of dye bath exhaustion and fixation of the industrial dyes. Hence, surface modification is a necessary operation prior to coloration process in wool wet processing industries. Plasma treatment is an effective alternative for physiochemical modification of wool surface. However, optimum processing parameters to get the expected modification are still under investigation, hence this technology is still under development in the wool wet processing industries. Therefore, in this paper, treatment parameters with the help of simple dielectric barrier discharge plasma reactor and air as a plasma gas, which could be a promising combination for treatment of wool substrate at industrial scale were schematically studied, and their influence on the water absorbency, mechanical, and dyeing properties of twill woven wool fabric samples are reported. It is expected that the results will assist to the wool coloration industries to improve the dyeing processes.

Ultrasonic assisted improved dyeing of cellulosic fabric using Vat Blue 4

ABSTRACTThe need for eco-friendly tool in textile processing is the major concern of consumers and traders. The current study is aimed to use ultrasonic radiation for improvement of Vat dyeing of cellulosic fibers using Vat Blue 4. For this purpose, both fabric and dye solutions were ultrasonically treated for 15–60 min at variable dyeing conditions. Dyeing has been performed onto irradiated and un-irradiated fabrics using irradiated and un-irradiated dye solutions. It is found that good color characteristics are obtained if un-irradiated fabric is dyed at 55 C for 60 min using 50 mL of neutral dye bath. For optimization of vat dyeing conditions, 2.5 mL of sodium dithionite, 2 mL of acetic acid and 2 mL of hydrogen peroxide at redox conditions have been optimized. Organization of International Standards (ISO) standard methods employed onto variable shades for colorfastness show that the Ultrasonic treatment has improved the rating of color characteristics. It is concluded that the Ultrasonic treatment has been proved as a cost- and time-effective tool for Vat dyeing of cellulosic fabric under mild conditions.

Microwave-assisted sustainable dyeing of wool fabric using cochineal-based carminic acid as natural colorant

ABSTRACTThe revival of natural dyes in textiles is gaining popularity due to their sustainable nature. The current study has been undertaken to improve the dyeing behaviors of cochineal-based natural dye (carminic acid) for wool dyeing under the influence of microwave treatment. For the purpose, wool fabric and extract obtained from cochineal insects (Dactylopius coccus costa) were irradiated for 1–6 min. The nature of dye bath (pH) and dyeing temperature were optimized using optimal irradiation conditions. To make dyeing process more sustainable and eco-friendly, bio-mordants and chemical mordants have been employed at optimal conditions. It is found that microwave treatment of extraction for 5 min is suitable to get darker shades with acceptable color characteristics using unirradiated wool fabric. K/S was found using acidic dye bath of cochineal insect of pH 1 for dyeing unirradiated fabric at 70°C using acidic extract of Cochineal bugs. Suggested ISO standards for color fastness revealed that 5% of henna and 3% pomegranate as bio-mordant have not only given high color depth but also rated excellent fastness properties as compared to chemical mordants used. It is found that MW treatment has not only improved the dyeing behavior of carminic acid but also enhanced the color characteristics.

Silver nanoparticles catalyzed reductive decolorization of spent dye bath containing acid dye and its reuse in dyeing

Decolorization of spent dye baths after dyeing of nylon, silk and wool fabrics with C.I. Acid Red 249 was attempted followed by their reuse in repeated dyeing. The system comprised of a non-sulfur reducing agent, sodium borohydride, along with silver nanoparticles synthesized by plant mediation technique using fresh curry leaves (Murraya koenigii). Response surface methodology was used to optimize the conditions of decolorization for reproducibility of results. Box-Behnken design matrix with three variables namely, dosage of nanoparticles, concentration of reducing agent and time of treatment, was employed to design the experimental runs. Analysis of variance was employed to estimate the statistical parameters and evaluate the statistical significance of the model. Fisher’s F- test was used to evaluate the quality and model terms. Three-dimensional response surface plots were used to study the interactive effect of operating variables on the response. Decolorized spent dye bath solutions were reused up to five times to dye fresh samples of nylon, silk and wool with the same dye. Negligible difference was observed in color depth and the fastness properties were identical for all the dyed samples even with respect to that dyed using dye liquor made from fresh water. Phytotoxicity studies revealed considerable reduction in toxicity of Acid Red 249 dye due to degradation. Thus, the treatment system for dye decolorization and repeated use of decolorized dye bath in dyeing was successful.