Eco-friendly Dyeing Research Articles

Structural study and molecular docking insights into laccase-mediated dye degradation

Industrial wastewater often contains harmful dyes, posing significant environmental challenges. This study used computational tools to investigate the interactions between the low-degradability Azo dye, Reactive Blue 19, and laccase enzyme from two fungi species, Lentinus sp. WR2 and Trametes versicolor, as well as the protein Xyn5B (GH30) from Bacillus sp. BP7. Physiochemical characterization indicated acidic properties for Lentinus sp. WR2 and T. versicolor, while basic characteristics for Bacillus sp. BP7. Secondary structure (SOPMA analysis) revealed that most laccases had random coiling, enhancing protein flexibility. The negative GRAVY index revealed favorable water interaction for Lentinus sp. WR2 and Bacillus sp. BP7. The ERRAT plot validated the laccase 3D structure. The molecular docking results were compared using active site prediction and docking score. Lentinus sp. WR2 is linked with Reactive Blue 19 through a single residual amino acid THR 168; T. versicolor is linked through GLY 101, TRP 98, and TRP 512; and Bacillus sp. BP7 exhibited four linkages: VAL 262, TYR 263, TRP 117, and THR 260. The molecular docking results showed that Xyn5B demonstrated laccase activity and bound effectively with Reactive Blue 19, outperforming a commonly used fungal laccase in dye degradation. These findings enhance our understanding of enzyme-substrate interactions and highlight the potential of Xyn5B in eco-friendly dye degradation.

Eco-Friendly Dyeing Processes of Nylon 6.6 Woven Fabrics with Used Coffee Grounds (UCG)

The increasing demand for sustainable practices in the textile industry has led to the exploration of natural dyes and eco-friendly dyeing processes. This study focuses on the potential of used coffee grounds (UCG) as an eco-friendly natural dye for Nylon 6.6 woven fabrics. Five dyeing processes were evaluated, varying in the use of mordants and acids, to assess their impact on the color saturation, colorfastness to laundering, and crocking resistance of Nylon 6.6. fabric. The processes included a control with no mordant or acid and others that incorporated tannic acid, acetic acid, and ferrous sulfate heptahydrate. The results demonstrated that process 4, which combined tannic acid pre-mordanting with acetic acid in the dye bath, provided the best balance between color saturation and colorfastness. Process 2, utilizing only tannic acid, offered some durability in laundering and crocking tests. Process 5, being the least eco-friendly process, demonstrated high color saturation, but it performed poorly in colorfastness to crocking, which means that it released the UCG-based dye after rubbing the dyed Nylon 6.6. fabric. The findings confirm that UCG can be an effective and sustainable natural dye for Nylon 6.6, with pre-mordanting and acid treatment significantly enhancing dye uptake and retention. However, further research is needed to optimize color intensity and expand the application of UCG in textile dyeing.

Eco-friendly dye degradation: advanced Gd-Ni co-doped Ba-hexaferrite photocatalyst for methyl green removal

Eco-friendly dye degradation: advanced Gd-Ni co-doped Ba-hexaferrite photocatalyst for methyl green removal

Sustainable Assessment of Bio-Colorant from Bakain Bark (Melia azedarach L.) for Dyeing of Cellulosic and Proteinous Fabric.

The current study proceeded to reduce the environmental hazards spreading worldwide due to synthetic dyes. To overcome these problems, eco-friendly natural dyes are introduced as alternative sources of synthetic dyes. The present study was focused on exploring the bio-colorant of the aqueous and acidic extract of the bark of Melia azedarach L. for the dyeing of both silk and cotton samples. The results of the extraction medium specified that the aqueous extract gave maximum colorant solubility and upon fabric dyeing produced higher color strength in contrast to the acidic medium. The optimization experimentation data showed that excellent color strength of silk fabric was found at 45 min dyeing time duration, in 35:1 mL dye extract, and using 2% salt (NaCl) as an exhausting agent, whereas cotton fabric showed the maximum K/S value at 60 min dyeing time, in a 45:1 mL liquor ratio, and with the use of 2% salt. Bio-mordants produce different shades on both fabrics. Bio-mordanting experiments on silk revealed that pre-mordanting with 2% turmeric and 3% pomegranate, and post-mordanting using 3% turmeric and 2% pomegranate produced a darker shade. In the case of cotton, the pre-mordanted samples with 2% turmeric and 3% pomegranate and the post-mordanted samples with 4% turmeric and 4% pomegranate gave the highest color strengths. All the mordanted samples gave excellent fastness ratings. Overall, it has been found that Bakain bark proved to be an excellent source of tannin. The result of this study showed that it could be a cost-effective and eco-friendly dye source for textile progress.

Sustainable Water Treatment: Harnessing Mining Waste as Catalysts for Sicomet Green Degradation

This paper presents a novel circular economy approach to water remediation that focuses on creating sustainable systems by utilizing mining waste from El-Ouenza, Tebessa, in the east of Algeria. Waste materials are employed as catalysts in Fenton and photo-Fenton processes. Two cases were studied: the conventional and the modified heterogeneous photo-Fenton at a pH of 3 and under modified pH conditions for degrading Sicomet Green food dye ZS120. Catalysts were characterized through various analyses. Catalyst performance and dye degradation were examined for raw and calcined waste at 500°C. Parameters like catalyst amount, sodium sulfite concentration, oxalic acid, and pH were optimized for both systems, with and without ligand. The first system achieved 91.5% mineralization using 0.15 g L-1 catalyst, pH of 3, and 0.45 mM Na2SO3 in 90 minutes under sunlight. The second reached 78.5% efficiency with variable conditions. Kinetic models demonstrated a first-order model for both photo-Fenton degradation and mineralization under sunlight. These findings guide eco-friendly dye degradation via mining waste-based catalysts in photo-Fenton systems, supporting sustainable wastewater treatment.

Eco-Friendly Dyeing and Functional Finishing of PET Fabric at Mild Conditions

Eco-Friendly Dyeing and Functional Finishing of PET Fabric at Mild Conditions

Enhanced light absorption and charge carrier’s separation in g-C3N4-based double Z-scheme heterostructure photocatalyst for efficient degradation of navy-blue dye

ABSTRACT Effective wastewater treatment is essential due to the dye environmental threats. Photocatalysis offers an eco-friendly dye degradation solution. Herein, we report a double Z-scheme photocatalyst, i.e. LaFeO3/Boron-doped g-C3N4/Fe2O3 (LFO/B-CN/FO), fabricated via a hydrothermal method. The formation of this ternary system is supported by structural, surface, and morphological analyses. Differential scanning calorimetry and thermal gravimetric analysis demonstrated the crystallization behavior of the composite. Because of synergetic effects in the ternary composite and boron doping, the optical band gap energy is reduced to 1.6 eV. Under visible light irradiation, the LFO/B-CN/FO nanocomposite degraded navy-blue dye by 98% in 130 min at neutral pH, surpassing CN, B-CN, and binary composites of B-CN with LFO and FO. The degradation process was rationalized using pseudo-first- and pseudo-second-order kinetic models, which confirmed high catalytic efficiency. The double Z-scheme heterojunction enhanced light absorption, charge separation, and carrier lifetime, hence improving the photocatalytic activity. Overall, the as-fabricated LFO/B-CN/FO ternary composite outperformed reference catalysts in terms of chemical reactivity, optical characteristics, and electrical performance. This work opens up a new route for the design and fabrication of double Z-scheme ternary composite photocatalysts for potential wastewater treatment and renewable energy applications.

Eco-friendly dye from the fruits of Memecylon randerianum S. M. Almeida & M. R. Almeida – An application study

Over the last few years, the global scenario has been witnessing an escalating urge to develop and use more eco-friendly products, like natural plant-based dyes, due to growing awareness about the harmful effects of synthetic products on mankind and nature. The present study is a novel eco-friendly textile application approach of natural fruit dyes extracted from Memecylon randerianum. Fresh aqueous fruit extracts were applied to cotton fabrics, and colour variations were achieved by pre-mordanting using both chemical and natural mordants. In addition to this, the effectiveness of memecylon dye in combination with turmeric dye was also evaluated. Various important attributes like colour strength, colour fastness, and a loss percentage of colour were analysed based on reflectance. Fabric dyed with mordant yielded darker bluish-purple to black shade than those dyed without mordant. However, the combination dye yielded brighter hues of yellow and green. In general, the dye showed moderate to very good fastness with the least loss percentage of colours. Tannins, a major class of compounds contributing to the dyeing potential of the plant part, were also quantified. Besides these, the dye also showed positive antimicrobial activity against the bacterial strains Staphylococcus aureus and Salmonella typhi. Hence, owing to its multiple favourable qualities, the study revealed that fresh dye extracts from M. randerianum fruits could be used as an effective eco-friendly alternative to hazardous synthetic dyes.

Environmentally sound recycling of agricultural waste: A sustainable approach to develop bio-functional art textile

The agricultural processing industry produces a large amount of waste on a global scale whose disposal is simultaneously a nuisance and of special interest. The by-products are rich in bioactive phytoconstituents that might be beneficial to the production of bio-functional textiles. The present work uses agricultural wastes for the eco-friendly dyeing of woolen yarns. Response surface methodology based on 23- Central Composite Design was used to design experiments, evaluate the main dyeing parameters, develop efficient mathematical models to predict the dyeing process, and optimize the procedure. The quadratic regression models developed were found to be statistically significant using ANOVA, with R2 -value of 0.9734 and 0.9820 for color strength and lightness responses, respectively. Also, eye-soothing tone and hues with a good resistance to durability (4–5) and light (4) were achieved. The banana shell and gallnut bio-mordants improved UV protection by up to 25.33% and 59.79%, respectively. Generally speaking, the results showed that C. Oblonga leaf as well as gallnut and banana shells could be used as whole crop products in an ecologically sound textile dyeing process through a sustainable approach and that the proposed innovative application might serve as an attractive procedure for recycling and green waste management.

Electrocatalytic hydrogen evolution coupled with dye hydrogenation reactions for sustainable wastewater treatment using transition-metal (Fe, Co, Ni, Cu) nanoparticles with ZnO nanowire supports

A water electrolysis coupled with chemical reduction strategy is proposed to realize sustainable wastewater treatment. Correspondingly, a series of transition-metal (e.g., iron, cobalt, nickel and copper) nanoparticles anchored on zinc oxide nanowire array (ZnO NA) with bifunctional catalytic activity for hydrogen evolution reaction together with dye hydrogenation reaction (HER/DHR) are developed, while their catalytic activity are comparatively investigated at the same time. This renewable strategy with environmental and economic benefits exhibits high-efficiency treatment capability towards various dye wastewaters. For example, a typical system based on nickel nanoparticles with ZnO NA supports, which exhibits higher catalytic activity towards the HER/DHR than those of other three counterparts under the same conditions, can transform waste 4-nitrophenol into valuable 4-aminophenol with an apparent rate constant of 36.95 × 10-3 min−1 and a conversion rate of 98.32 %, thereby achieving dye decolorization and resource regeneration simultaneously. Its efficiency is significantly superior to that of chemical method dependent on traditional reducing agents and commercial nickel materials, demonstrating its stronger competitiveness. It is mainly benefited from the interface synergistic effect of nickel nanoparticles and zinc oxide nanowires. This novel system is expected to replace conventional sewage remediation technologies for efficient, inexpensive, and eco-friendly dye degradation, and thus is very important for energy and environmental sustainability.

Synthesis and characterization of sustainable blue dyes: Enhancing diffusion on nylon fabrics with supercritical CO2 for eco-friendly dyeing methods

A very convenient method was developed to synthesize five dispersed anthraquinone dyestuffs using the readily available starting material 1,4-diaminoanthroquinone. This dye was prepared for coloration on nylon fabrics with supercritical carbon dioxide (ScCO2). All the synthesized dyes were characterized by 1H NMR, 13C NMR, and HRMS techniques. The UV-Vis absorbance measurements for all the dyes were carried out, and the results indicated that the absorption peak wavelength of the dyes was approximately 570–641 nm in the blue region. Further, these dispersed dyes were dyed on nylon fabrics with supercritical CO2. After dyed fabrics were tested, the color strength of K/S value and color fastness were tested using like washing, crocking, and sunlight. Additionally, it determines the sweat fastness of dyed nylon fabrics under acidic and basic conditions. The dyes are readily involved in the nucleophilic addition of amino (-NH2, nylon) functional groups to nylon fabrics in an alkaline medium. Therefore, our results showed that these dyes are commercially the most satisfactory, environmentally efficient dyes and practically exhibit sufficient color uniformity.

Eco-friendly dyeing of cotton with natural colorants using natural mordants obtained from aloe vera

Due to sustainable and green processing requirements from buyers, the researchers are working on natural dyes to dye textile materials. In this study, cotton fabric was successfully dyed with a natural colorant which was extracted from black tea, and aloe vera was used as a natural mordant to enhance the fixation of natural dyes. The aqueous extraction method was used to extract colorant from black tea powder in a water bath at the temperature of 85–95 °C for 60 min. Three mordanting techniques were applied for cotton dyeing by changing parameters such as dye concentration (2, 4, 8 % o.w.f) and mordant concentration (20, 40, and 60 g/L). Pretreated cotton fabric was dyed on a high-temperature (HT) dyeing machine at 80 °C for 40 min at pH 5.5. The dyed cotton samples were analyzed for color strength (K/S), colorfastness, and antibacterial assessment (qualitative) using standard test protocols. The results showed that the maximum color strength value was achieved with 8 % dye and 60 g/L mordant using pre mordanting method. The dyed fabrics revealed excellent colorfastness to washing, whereas the color fastness to light, perspiration, and crocking was satisfactory. The antibacterial property of the dyed fabric was also satisfactory which is confirmed by no colonial growth on or below the samples. In a nutshell, this study presented an ecofriendly approach using black tea leaves and aloe vera contributing to green and sustainable production.

Utilization of factory tea (Camellia sinensis) wastes in eco-friendly dyeing of jute packaging fabrics

Eco-friendly dyeing of jute packaging fabrics was evaluated using aqueous extraction of factory tea (Camellia sinensis) wastes. Jute and factory tea wastes are available in Bangladesh and jute bags are used for packaging of various exportable agricultural commodities. The extract of factory tea waste (FTW) is dark coffee colored and it was characterized by attenuated total reflection-fourier transform infrared (ATR-FTIR) and microbial analysis. Nontoxic, non-allergic and eco-friendly natural dyeing process of jute packaging fabrics using extract of FTW were developed and optimized. Metal mordants 10 % on the weight of fabric was used to get the fastness properties of dyed jute fabric. The methods of application of mordants were pre-mordanting, simultaneous or meta-mordanting and post-mordanting. The color fastness and tensile properties were measured for all jute packaging fabrics and it is found that the dyed jute packaging fabrics showed a slight decrease in tensile breaking force (N) than undyed jute packaging fabric. The highest color fastness obtained with the meta mordanting method with ferrous sulfate mordant in a shade of dark coffee. The results of the color fastness for light and washing showed an excellent value of grade 4–5.

Eco-friendly dyeing of leather and wood samples using Parthenocissus quinquefolia L. fruits aqueous extract

The present study is relevant to extracting natural colorant from Parthenocissus quinquefolia L. fresh fruits and applying the extracted dye on leather and wood samples in the presence and absence of various mordants. The effect of mordant type (copper sulfate (CuSO4.5H2O) ferrous sulfate (FeSO4.7H2O) and alum (KAI(SO4)2.12H2O) with different mordanting methods (pre-mordanting, meta-mordanting, post-mordanting) on dyeing quality was also examined. The effects of mordants on the color of dyed samples were investigated in terms of CIELab (L*, a*, b*) and K/S values. The dyed samples' light, washing, and rubbing fastness were evaluated according to ISO standards. Although generally good fastness values were obtained for all three mordants, light fastness was low. These results suggest that P. quinquefolia fruits have sufficient potential in dyeing leather and wood.

Pongamia pinnata flowers powered Ag doped CuO nanoparticles for eco-friendly dye degradation and antimicrobial applications: a mechanistic approach

Pongamia pinnata flowers powered Ag doped CuO nanoparticles for eco-friendly dye degradation and antimicrobial applications: a mechanistic approach

Investigation of process parameters for eco-friendly indigo dyeing of cotton fabric with reducing sugars

Purpose The application of indigo dyes in the denim industries has been criticised due to the introduction of non-renewable oxidation products into the environment. Previous studies have investigated that reducing sugars can be used as green alternatives to sodium dithionite in the indigo dyeing of cotton fabric owing to their reduced and stable redox potential in the dye bath. The purpose of this study was to dye denim cotton fabric with indigo dye using various reducing sugars and alkalis. The use of sucrose and potassium hydroxide (KOH) for indigo dyeing has been explored for the first time. Design/methodology/approach A mixed factorial design with four variables including alkali, pH, number of dips and type of reducing sugar at different levels was studied to identify a significant correlation between the effect of these variables on the colour strength and fastness properties of the dyeings. Findings Investigations were made to examine the significant factors and interactions of the selected responses in the eco-friendly dyeing method. This process has the potential to reduce the load of sulphite and sulphate generated in the dyebath due to the use of a conventional reducing agent, sodium dithionite. The colour strength of the dyeing reduced with fructose was found to be better than other reducing sugars and significantly influenced by the number of dips, pH levels and the interaction between pH and reducing sugars. Using fructose for indigo dyeing with two dips at a pH of 11.5, using KOH as an alkali, results in higher colour strength values. The fastness properties of the indigo-dyed sample with reducing sugars ranging from fair to good or good to excellent. Specifically, colour change receives a rating of grey scale 3–4, staining 4–5, dry rubbing 4 and light fastness 3–4. These assessments hold true across various factors such as the type of reducing sugar, alkali, pH and the number of dips. The optimised parameters leading to improved colour strength and fastness properties are also discussed. Originality/value This dyeing technique is novel and a green alternative to dithionite denim dyeing. This process is found to be useful for indigo dyeing of denim fabric leading to reduced and stable redox potential in the dyebath and acceptable colour strength of the dyed fabric.

EXTRACTION AND CHARACTERISATION OF NATURAL DYE FROM ORANGE PEEL FOR TEXTILE APPLICATIONS

Awareness of the need to protect the environment and people's health has led to an intensification of concerns for obtaining sustainable products and processes. Toxic waste created during the production and use of synthetic dyes has an impact on both human and environmental health. As a result, natural dyes are more secure and safer than synthetic dyes. This study is significant because it has the potential to help develop sustainable and environmentally friendly textile dyeing techniques. In this study, a natural dye was successfully extracted from orange peel (Citrus recticulata Rutaceae) which was applied on textile fibre and was found to be partly effective for eco-friendly dyeing applications. The extracted dye does not have a good wash fastness, which is the ability of the fabric to retain its colour after washing. This weakness is demonstrated by carrying out a Fourier transform infrared (FTIR) analysis where the potential binding mechanisms between the dye and the textile fibres was revealed. Different functional groups can interact with the fibre’s functional groups, affecting the dye's affinity for the fabric and its overall colour fastness properties. Findings show that dyes from orange peels showed promise in this study, but need to be improved further. Therefore, the study suggests that further research is needed to optimize the dyeing process and improve the fabric's resistance to washing and other environmental factors.

Valorization of Natural Dye Extracted from Date Palm Pits (Phoenix dactylifera) for Ecofriendly Dyeing of Bicomponent Polyester Filaments

Valorization of Natural Dye Extracted from Date Palm Pits (Phoenix dactylifera) for Ecofriendly Dyeing of Bicomponent Polyester Filaments

Multifunctional Analysis of Banana Leaves Extracts for Dyeing Properties of Pima Cotton Fabric Using Different Mordants

Introduction Natural dyes have become very important for decades based on their extensive properties compared to synthetic dyes. Pima cotton was dyed with natural dyes derived from plants using mordants, a crucial step in modern industry. Objective This study explores the efficacy of banana leaf-extracted natural dyes with mordants in dyeing Pima cotton, examining color properties, chemical attributes, and fastness while exploring the potential for industrial applications. Methods In this study, banana leaf extracts were utilized for dyeing Pima cotton with mordants. The investigation assessed the multifunctional properties of alkaline and acetone using UV-Vis and FTIR or analyzed the dyed fabric's UPF. Applied to pre-mordanted Pima cotton, our dye interacts with various mordants like ferrous sulfate (Fe2SO4), copper sulfate (CuSO4), and potassium dichromate (K2Cr2O7). Factors influencing dye fixation on Pima cotton, including cellulose and mordants, were examined. Treated and untreated fabric samples were tested for tensile strength and elongation. Dyeing performance was assessed using color parameters (K/S, L*, a*, b*, ΔE) using the Kubelka–Munk equation and fastness properties, with consistent results compared to standard protocols. Results The study on natural dye extraction from banana leaves has yielded promising outcomes, showcasing the effectiveness of mordants in dye fixation on cotton. The results demonstrate high tensile strength, color strength, and fastness properties in the dyed Pima cotton samples. Statistical analysis highlighted the nuanced relationship between mordants and dyes. The study's comprehensive approach, UV-Vis and FTIR analyses, dyeing temperature optimization, and phytochemical screening, confirming the presence of flavonoids, saponins, alkaloids, and other bioactive compounds, positions banana leaf extracts as a sustainable and versatile resource for eco-friendly textile practices, offering a compelling alternative to synthetic dyes. Conclusion The study reveals Pima cotton's promising potential for eco-friendly dyeing, optimizing cost, time, and space for future sustainable textile applications.

Exploring the requirements of reactive dyes in eco-friendly dyeing process: The relationship between dye structure, dyeing properties, and eco-friendly dyeing techniques

Herein, four heterobifunctional brilliant yellow dyes containing different numbers of sulfonic groups (MRY-1–MRY-4) were designed to investigate the relationship between the dye structure, dyeing properties, and the eco-friendly dyeing technique. The solubility, stability, substantivity, reactivity, and colorimetric properties of the dyes were studied. The substantivity of the dyes was significantly reduced when the diazo component of the chromophores contained two sulfonic groups. The four dyes were then used to dye cotton fabrics using eco-friendly low liquor ratio dyeing and cold pad-batch dyeing techniques. For low liquor ratio dyeing, when the liquor ratio was 1:6, the fixation rates of MRY-1, MRY-2, and MRY-3 were 84.9 %, 71.1 %, and 75.0 %, respectively. MRY-4 was not suitable for exhaust dyeing but could be used in cold pad-batch dyeing, in which its fixation rate on cotton fabric reached 93.8 %. However, MRY-1 cannot be used to dye cotton by cold pad-batch dyeing due to its low alkali resistance and resulting poor stability. In a similar chromophore structure, increasing the number of sulfonic groups increased the brightness value of the dye but also made the dye greener and bluer. The dry and wet rubbing fastness of cotton dyed with the four reactive dyes was grade 4–5 and 3–4, respectively. The wash fastness to color change and staining reached grades 4 or 4–5, while the light fastness of MRY-1 and MRY-3 was grade 3–4 and that of MRY-2 and MRY-4 was grade 4–5.