Dye Color Research Articles

Investigating how the dye colour is impacted when chemically separating polyester-cotton blends

Blended textile fabrics with dyed cotton and polyester (PET) fibres intimately mixed are extensively used in the textile industry. Separating and recycling these blends cannot be performed by conventional mechanical or chemical recycling processes, and this is contributing significantly to the global textile waste problem. Here we demonstrate an approach to separate coloured cotton and polyester blends, and the dye is retained in the separated polyester and cotton components. The separation was achieved via chemical dissolution of cotton using a co-solvent system of ionic liquid and dimethyl sulfoxide, from which regenerated cellulose fibres could be directly wet spun. The polyester component was left intact and recovered via filtration. The recovered products were characterised for thermal, chemical, mechanical, colour strength, and morphological properties.

Role of SA-g-(PAA-co-AM)/CdS Hydrogel: As Photocatalytic for Decolonization Methyl Red Dye as a Pollutant from Aqueous Solution

The photocatalytic method to remove the color of methyl red (MR) dye from aqueous solutions in the presence of SA-g-(PAAco- AM)/CdS hydrogel has been studied with the utilization of artifi cial UV-A light source. The properties of the hydrogel /Csd were studied using techniques (FESEM, TEM, and TGA).The eff ects of several factors, like time of irradiation, amount of SA-g-(PAA-co-AM)/CdS hydrogel, initial concentration of MR dye onto photo-catalytic degradation, were studies . The rate of de-colorization was found to increase remarkably with increased time of irradiation. Under best conditions from pH=5.4 and temperature at 25°C , the extent of removal color of MR dye was 100% after 1hr of irradiation at a concentration 15 mg/L. And found the initial rise in rate of MR degradation with increase in quantity of SA-g-(PAA-co-AM)/CdS hydrogel is due to an increase in number of active sites on the hydrogel of photocatalyst the rate of degradation, and photodegradation capacity is rising with increasing light intensity.

Extraction of Anthocyanin from Rose Petals for Coloration of Biomordanted Wool Fabric

Natural products have gained worldwide favor due to their sustainable and ayurvedic nature. In this study, rose containing anthocyanin was explored as a source of yellowish–pink natural colorant for wool dyeing using various solvents (aqueous, alkaline, acidic, and basified methanol). Dyeing of wool was performed by optimizing the following parameters: pH, temperature, time, and salt concentration. It was observed that aqueous extract with a pH of 3 employed at 80 °C for 35 min with the addition of 4 g/100 mL salt, acidic extract with a pH of 2 employed at 40 °C for 35 min with the addition of 2 g/100 mL salt, alkaline extract with a pH of 1 employed at 80 °C for 45 min with the addition of 3 g/100 mL salt, and methanolic extract with a pH of 2 employed at 80 °C for 45 min with the addition of 4 g/100 mL salt resulted in high tint (K/S) values. To improve the colorfastness properties, salts of iron (Fe+2), aluminum (Al+3), and tannic acid (Tn) were used as chemical mordant, whereas turmeric and pomegranate were used as biomordants. Iron (Fe+2) and pomegranate resulted in shades with good colorfastness characteristics. The plant extract and dyed fabrics were also evaluated against Gram-positive and Gram-negative bacteria Staphylococcus aureus and Escherichia coli, respectively, to observe their antibacterial potential. The results indicate that wool fabric dyed with naturally sourced rose petals can be used as valuable antibacterial fabric due to the presence of various bioactive compounds by dissipating the effect of allergy-causing synthetic dyed fabrics.

Decolorization of Acid Dye Using Lowcost Organic Adsorbents

Dyes are extensively used in industries. Dye color in water courses reduces photosynthetic activity which further affects the aquatic life. It also causes skin cancer and allergies to human beings. It's imperative to remove dye color from an aqueous dye solution. The objective of the present study is to find the efficiency of low-cost organic adsorbents in the decolorization of Color Index Acid blue 45 dye from an aqueous solution. The organic adsorbents used in the present study are Gigantea Leaves (GL), Curcuma Longa Leaves (CLL), Moringa Oleifera (MO) and Citrus Sinensis (CS). The study consists of nonagitated flow experiments at optimum pH with varying dosages and contact time. The results showed that excellent color removal of dye can be achieved with adsorbents at optimum pH of 4 with Gigantea Leaves of 85%, good color removal of 78% and 76% with Curcuma Longa Leaves and Moringa Oleifera, and, moderate color removal of 53% with Citrus Sinensis. The isothermal equilibrium sorption data was well fitted into the Freundlich Isotherm. Kinetic studies states that chemisorption is the rate limiting step. Gigantea leaves, Curcuma Longa and Moringa Oleifera show great promise in decolorizing aqueous solution of C.I. Acid Blue 45.

Azo Dye Removal from Aqueous Solution by Powder Graphite: Investigation of Parameter Effects and Optimization by Box-Behnken Design

Industrial wastewaters containing dyes comprise organics that are difficult to biodegrade and when they are discharged to receiving bodies, they cause serious impacts on environment. Therefore, this wastewater requires advanced treatment besides conventional ones. Adsorption is accepted one of the favorable processes, which can be applied integrative to conventional systems during the treatment of this wastewater. In addition to the effectiveness of the materials to be utilized in the adsorption process, their cost and availability are also very important factors. In this study, the efficiency of environmentally friendly, cost-effective powdered graphite was investigated in the removal of diazo type dye (Direct Red 243) from aqueous solution by adsorption. For this purpose, Response Surface Method was applied via Box-Behnken Design and the most effective parameters were investigated in dye adsorption with graphite. Also, the morphology of the graphite before and after adsorption was scanned by Scanning Electron Microscopy. Adsorption study was carried out in batch mode and pH (2-10), adsorbent amount (0.1-1.5 g) and time (15-65 min) were designated as experimental parameters. It has been observed that the most effective parameter in color removal of dye was pH and at low values of this parameters the higher efficiencies were obtained. Additionally, it was observed that the increase in the amount of adsorbent increased the efficiency, and time had no significant effect besides two parameters. Almost complete decolorization (98%) was acquired at pH 2 with 1.5 g adsorbent for 40 min of study. As a result of the study, even it is not improved with further applications, graphite can be effective for anionic dye color removal under acidic conditions by its pristine form.

Efficient and accurate KRAS genotyping using digital PCR combined with melting curve analysis for ctDNA from pancreatic cancer patients

A highly sensitive and highly multiplexed quantification technique for nucleic acids is necessary to predict and evaluate cancer treatment by liquid biopsy. Digital PCR (dPCR) is a highly sensitive quantification technique, but conventional dPCR discriminates multiple targets by the color of the fluorescent dye of the probe, which limits multiplexing beyond the number of colors of fluorescent dyes. We previously developed a highly multiplexed dPCR technique combined with melting curve analysis. Herein, we improved the detection efficiency and accuracy of multiplexed dPCR with melting curve analysis to detect KRAS mutations in circulating tumor DNA (ctDNA) prepared from clinical samples. The mutation detection efficiency was increased from 25.9% of the input DNA to 45.2% by shortening the amplicon size. The limit of detection of mutation was improved from 0.41 to 0.06% by changing the mutation type determination algorithm for G12A, resulting in a limit of detection of less than 0.2% for all the target mutations. Then, ctDNA in plasma from pancreatic cancer patients was measured and genotyped. The measured mutation frequencies correlated well with those measured by conventional dPCR, which can measure only the total frequency of KRAS mutants. KRAS mutations were detected in 82.3% of patients with liver or lung metastasis, which was consistent with other reports. Accordingly, this study demonstrated the clinical utility of multiplex dPCR with melting curve analysis to detect and genotype ctDNA from plasma with sufficient sensitivity.

Enhanced interaction of dye molecules and fibers via bio-based acids for greener coloration of silk/polyamide fabric

Multi-component fabrics combined with natural silk fibers and man-made polyamide fibers are good choices for high-quality textile owing to the remarkable comfort and excellent resistance. The silk/polyamide fabric colored with reactive dyes generally shows good fastness, but the problems still remain that large dye effluent discharge, high chemical consumption, and long-time dyeing process. To counter these issues, herein we report a greener coloration method without any salt or alkali added for the coloration of silk/polyamide fabrics. Three bio-based acids like acetic acid, citric acid, and tannic acid were introduced into the dye solution to improve the interaction of dye molecules and fibers. Much of the focus has been given to understand the mechanism between the dye molecules, bio-based acids and fibers, which was determined through dynamic surface tension and UV–visible absorption spectrum measurement. Through this, it was found that the citric acid due to its maximum number of carboxyl groups than acetic acid and tannic acid promoted the disaggregation of dyes and enhanced the dye diffusion to fiber surface. As a result, the dye fixation and color strength of silk and polyamide fibers were all significantly improved when using citric acid at pH 6 with the steaming for 5 min. From the SEM analysis, it was seen that the surface morphology of silk/polyamide fibers was not so much affected. Compared with the traditional dyeing method, this method exhibited enhanced color performance with a shorter dyeing process, lower chemical consumption and nice fastness property. This work presented a potential and practical application of natural additives in the dyeing of multi-component fabrics to achieve eco-friendly and high-quality textile products.

Extraction and Application of Pumpkin Peel Colorants for Natural Textile Dyeing

This preliminary research discusses the extraction of colorants from pumpkin peel as vegetable dyes and the potential dyeing capability of silk and cotton fabrics. For pumpkin extracts, thermal gravity analysis has verified the range of temperature for application, while a combination of UV–vis spectra and high-performance liquid chromatography analysis confirmed the main colored components and structural characteristics. It was found that the extracts of this vegetable dye have excellent thermal stability as well as stability in neutral and acid conditions. With the objective of achieving the greatest absorbency rate of extracted solution, the following optimum extraction conditions were obtained: 100% ethanol, an extraction temperature of 70°C, an extraction time of 60 min, and a material-to-liquor ratio of 1:10. To attain the highest dyeing uptake rate and K/ S values, the optimum dyeing profiles with meta-mordanting for silk fabrics were found to be 95°C, 90 min, pH 5.5, and a liquid ratio of 1:60. The optimum dyeing profiles with meta-mordanting for cotton fabrics were 95°C, 90 min, and a liquid ratio of 1:60. Nearly all colorfastness results for silk and cotton fabrics met the basic requirement of the China National Standard, except a few.

In Situ Adsorption of Red Onion (Allium cepa) Natural Dye on Cellulose Model Films and Fabrics Exploiting Chitosan as a Natural Mordant.

Synthetic dyes and chemicals create an enormous impact on environmental pollution both in textile manufacturing and after the product's lifetime. Biobased plant-derived colorants and mordants have great potential for the development of more sustainable textile dyeing processes. Colorants isolated from biomass residues are renewable, biodegradable, and usually less harmful than their synthetic counterparts. Interestingly, they may also bring additional functions to the materials. However, the extraction and purification of the biocolorants from biomass as well as their dyeing efficiency and color fastness properties require a more thorough examination. Here, we extracted red onion (Allium cepa) skins to obtain polyphenolic flavonoids and anthocyanins as biocolorants, characterized the chemical composition of the mixture, and used a quartz crystal microbalance and thin films of cellulose nanofibrils to study the adsorption kinetics of dyes onto cellulose substrates in situ. The effect of different mordants on the adsorption behavior was also investigated. Comparison of these results with conventional dyeing experiments of textiles enabled us to determine the interaction mechanism of the dyes with substrates and mordants. Chitosan showed high potential as a biobased mordant based both on its ability to facilitate fast adsorption of polyphenols to cellulose and its ability to retain the purple color of the red onion dye (ROD) in comparison to the metal mordants FeSO4 and alum. The ROD also showed excellent UV-shielding efficiency at low concentrations, suggesting that biocolorants, due to their more complex composition compared to synthetic ones, can have multiple actions in addition to providing aesthetics.

Coloration Modeling and Processing of Commodity Plastic Buttons in Supercritical Carbon Dioxide.

We examined the color processing of the commodity plastic buttons made of acrylic, polyester, nylon, and casein with scCO2. The buttons' dyeing color depth (K/S) was measured over a wide range of scCO2 and correlated accurately with the response surface method. Moreover, we measured the solubility of C.I. Disperse Red 22 in scCO2 to formulate a dye-sorption model for the K/S value in the color processing of the plastic buttons. Finally, the dye-sorption model for the K/S value combining the dye solubility in scCO2 with the dye diffusion inside the buttons successfully represented the color processing of the buttons.

Coagulation Study on Extracted Algal Alginate from Red Algae as Natural Coagulant for Remediation of Textile Dye Congo Red

In the present study, extracted algal alginate from red algae as natural coagulant was used for removal of textile dye congo red (CR) from water. In developing countries like India, only about 10% of the wastewater being generated is treated, whereas the remaining 90% is discharged into the water bodies as it stands. Color and turbidity are the most common problems in the disposal of wastewater. The removal of color is one of the key challenges in wastewater treatment. For the coagulation process, the synthetic textile wastewater samples had CR concentrations of 50, 100, 150, 200, and 250 mg/L and varying initial pH of 4, 5, and 6. Different dosages of calcium and alginate (1, 2, 3, 4, 5, and 6 g/L) were used to perform the experiments. The obtained results exhibited that the effectiveness of color removal was higher at lower pH 4, and the calcium and alginate dosages are dependent on the CR concentration of the synthetic textile wastewater. These investigations demonstrating the higher efficiency of calcium alginate as a coagulant, where maximum color removal achieved over 95.05%. Increasing alginate dosages and residence times can enhance the performance of coagulation. Dye color is often present in real wastewater and needs to be removed before being reused or discharged to the environment.

EFFICIENT REMOVAL OF MAGENTA DYE FROM WATER BY BOTH NATURAL AND CHEMICAL COAGULANTS

Reactive magenta dye (RMD) has been removed from the aqueous solution by different coagulants such as natural coagulants Moringaoleifera (MO), Strychnos potatotrum (SP), and Alum chemical coagulants (AC) respectively. All these three coagulants were studied with various parameters to optimize the maximum removal %, like coagulant dosage from 10 ml to 60 ml, RMD concentration range of 100 mg/L to 500 mg/L, contact time between 10 min to 60 min, and pH kept neutral. The maximum percentage removal was achieved by SP coagulant at 60 min contact time, 100 mg/L dye concentration, and 60 ml coagulant dosage whereas MO and Alum achieved the maximum of 93% and 85% respectively. The results showed that MO seeds, SP seeds, and AC coagulants performed well in the removal of suspended solids and dye color. Furthermore, this research validated the preparation of low-cost eco-friendly coagulants and effective jar test methods for treating reactive dyes which are present in real textile water.

A three-state label programmed using a three-color microsphere of structural, fluorescent and dye colors

We have, for the first time, utilized the selective reflection characteristics of CLCs and the photochromic properties of SP to fabricate advanced tristate inks. The tristate ink achieves three different states under simple light illumination.

Komparativna studija sposobnosti bojenja konvencionalnih i organskih pamučnih tkanina

Cotton fiber, which is the most widely used natural fiber in the textile and paper industries, has a crucial environmental impact. Cultivation of conventional cotton consumes a lot of water and requires the usage of a higher amount of pesticides. Organic cotton is a more environmentally friendly alternative to its growing conditions. The characteristics of cotton change with the differences in growing conditions. In this study, the properties of yarns obtained from both conventionally and organically grown cotton were tested and analyzed. The properties of these yarns in the fabric structure were compared in terms of fabric performance. The produced fabrics were dyed in the cold-pad batch method with 5 different colors of reactive dyes, which are the most demanding colors in the ready-made garment industry. The physical properties and the fastness test results of the dyed organic and conventional cotton fabrics were investigated in detail to highlight the plant growing effects on the fabric behavior. Comparative color analysis and evaluation of the fabrics were made to discuss the performance of the fabrics. It is found that organically grown cotton is not only superior in quality but also has no negative eff ECT on fabric properties.

Surface-enhanced Raman spectroscopy hair analysis after household contamination.

Trace evidence found at crime scenes is rarely in an unsullied condition. Surface-enhanced Raman spectroscopy (SERS) is a modern analytical technique that can be used for the detection of artificial hair colourants (S. Higgins and D. Kurouski, Surface-Enhanced Raman Spectroscopy Enables Highly Accurate Identification of Different Brands, Types and Colors of Hair Dyes, Talanta, 2022, 251, 123762). However, contaminants pose a problem to collecting accurate spectra from the dyes. In this study, we sought to analyze how the different physical properties of contaminants can influence the collected spectra. We utilized 11 household substances of varying viscosity and opacity to contaminate hair dyed with permanent black or semi-permanent blue dyes. We discovered that contaminant opacity generally does not affect the spectral quality but that high contaminant viscosity does and that acidic substances could destroy the colourant's spectral identity altogether. Cleaning the contaminated hair with a water rinse allowed the underlying colourant to be identified in 21 out of 22 cases. Overall, this study provided a clearer understanding of the capabilities and limitations of SERS in forensic hair analysis.

Back to Black: A fashionable colour from Worth to Chanel

While menswear remained mainly dominated by black throughout the 19th century, the new bright and glowing colours of aniline dyes influenced women’s fashion, relegating black to a background trend. This article addresses the rise of black as a womenswear trend, from the popularity of “imperial black silks” during Second Empire fashion, and the revival of black in eveningwear in fin-de-siècle culture, to Chanel’s modern little black dress (1926) interpreted as the ultimate reaction against the gaudy colours inherited from the 19th century chromatic revolution. This research thus explores black as a fashionable colour related to material, popular and visual cultures, and discusses the notion of “artificial black” that emerges more generally from 19th century visual culture.

Fabrication of multifunctional cotton fabrics dyed with Coptis chinensis extract

Low dye exhaustion and poor colorfastness of cotton fabrics dyed with natural dyes were the inevitable issues, which may potentially limit their application in textile industries. Hence, there is great demand for improving dyeing performance of natural dyes to expand their application. This work presents a facile and efficient way to improve dye exhaustion and color fastness of cotton fabrics dyed with Coptis chinensis ( C. chinensis ) extract through fabric pretreatment and aftertreatment processes. The cotton fabrics were firstly treated with critic acid (CA) to increase their capacity of anionic sites. Enhanced effect of water repellent agent as the aftertreatment chemical, which was applied to improve washing fastness of dyed fabrics, was evaluated. The color characteristics, color fastness and functionalities of dyed fabrics were also assessed. The results indicated that pretreated cotton fabrics displayed higher color strength than the untreated fabrics. Additionally, the dyed fabrics treated with water repellent agents showed better washing fastness. The antibacterial activity of dyed fabric was increased up to 98% and the ultraviolet protection factor (UPF) value reached 349.69. What’s more, the dyed fabrics also exhibited excellent wrinkle resistance and waterproof property. The integration of antibacterial, antiultraviolet, antiwrinkle and waterproof properties in the cotton fabrics dyed with C. chinensis extract was a meaningful achievement, which exhibited great potential application in medical textile and garment. • Simultaneous dyeing and functional finishing were achieved by using C. chinensis extract. • Pretreatment of cotton fabrics with CA was beneficial for enhancing color strength. • Aftertreatment of dyed cotton fabrics with water repellent agent improve washing colorfastness. • The dyed cotton fabrics exhibit excellent multifunctional properties.

USE OF BI2S3 AS A PHOTOCATALYST FOR PHOTOCATALYTIC DEGRADATION OF TEXTILE AZO DYE REACTIVE BLUE 160 (RB160)

In apparel industries removal of the color of dye is one of the main problem. In the current work semiconductor photo-catalyst Bi2S3 utilized in photo catalytic decolorizing of textile azo dye Reactive Blue 160 under UV light. Spectrophotometric measurements of the reaction rate were made. It has been investigated how many variables, including dye concentration, photocatalyst quantity, and pH, affect reaction efficiency.

Designing Digital Color Library as Inventory Media for The Natural Dye of Indonesian Traditional Textile (Study Case: Classical Batik of Yogyakarta)

Textile coloring using natural colorant has its own unique value on each color results as well as in the color-making creation process itself. In addition to the decorative elements, Indonesian traditional textile also has distinct signature textile culture on its natural dye, for example Batik Klasik Yogyakarta which is well known for its brown soga color, a brownish color obtained from the colorant’s combination of jambal bark (Pelthophorum ferrugineum), tingi bark (Ceriops candolleana), and tegeran wood (Cudrania javanensis). Along with those ingredients, Batik Klasik Yogyakarta also uses indigo plant (Indigofera tinctoria) as its blue colorant and kapur tohor (Calcium Oxide) for pre and post mordant treatment. The designing of “Manékawarna” digital content output as content of mobile application would be a recommendation as it would be a data inventory media of Batik Klasik Yogyakarta natural dye. In order to make the color visual data suitable for digital device, the research requires fabrics dyed with Batik Klasik Yogyakarta natural dye ingredients and technique as samples for color identification study by digitalization method to obtain RGB color value. The natural dye color digital format data is designed to facilitate data preservation and its acquisition by individuals whom have interest on textile natural dye.

Variation in Colourants of the Dyes by Gamma-ray Irradiation

The emergency conservation of historical objects is necessary because several instances in which paintings and records were flooded owing to unusual weather conditions have recently been reported. Early action is especially important in preventing biodeterioration in case of flood damage. In this study, the feasibility of using gamma rays as a biological control method was assessed. Material stability was evaluated by applying different irradiation doses to natural dyes used in historical paintings and costumes. Sappan wood, gardenia fruit, and indigo were selected and prepared as natural dye samples using standard colorant materials. The fading behavior of the samples was analyzed by measuring their CIE L*a*b* color space values, and UV-Vis spectroscopy and liquid chromatography tandem mass spectrometry (LC-MS) were used to obtain their spectra. We confirmed that the dyes began to decompose upon exposure to gamma rays at a dose of 10 kGy. Irradiation at a dose of 50 kGy led to the complete decomposition of the chromophoric groups because the dye components could not be detected by LC-MS. Therefore, studying the influence of low-dose gamma-ray irradiation is necessary to preserve dye colorants. The data obtained in this study can be used as a foundation for further research on the influence of gamma rays on historical objects.