Textile Dyeing Industry Research Articles

Sustainable biotreatment of textile dye effluent water by using earthworms through vermifiltration

ObjectiveA research was conducted to explore the reuse possibilities of the textile dye effluent propagated from the textile dye industry. The current study reports vermiculture based effluent treatment method through the chief intention of interconversion of contaminated effluent water into ecologically harmless water. MethodsHence a new and typical technology, vermifiltration of effluent using wastewater eating earthworms has been evolved. ResultsOutcome recommended that vermifilter revealed maximal chemical oxygen demand (126 mg L−1), Biological oxygen demand (56 mg L−1), Total suspended solids (181 mg L−1) and Total dissolved solids (298 mg L−1) decreased by 85–89%, 76–80%, 73–77% and 71–76% by the result of vermifiltration. Bioavailability of some heavy metallic compounds such as Ni, Cd, Cu, Zn, Pb, and Cr brought down considerably during vermifiltration. Vermifilter and control metal accumulations ranged from 0.2 ppm to 2.34 ppm and from 0.10 ppm to 2.98 ppm respectively. The SEM illustration reveal that the morphology of the vermicast of control and vermifiltration which is differing significantly. When the concentration of textile dye sludge increases it also increases the destruction of tissues constantly. Histological of the gut domain exposed moderate harm in 50% dilution. ConclusionsTherefore, these studies concluded that vermifiltration can be used as an eco-friendly technique which can be considered the same as a paradigm for textile industries effluents remedial development.

A new technique to estimate percentage decolorization of synthetic dyes on solid media by extracellular laccase from white-rot fungus

The enormous colored effluent discharges due to increased usage of synthetic dyes in textile and other chemical industries pollute both freshwater and marine reservoirs and cause ecotoxicity and serious health problems. This issue needs to be addressed skillfully and demands an ecofriendly and economically feasible technique. Pertaining to this, the current study was focused on the use of a white rot fungus, Resinicium bicolor to decolorize and degrade a recalcitrant dye, Congo red (CR) through its extracellular laccase enzyme secreted by mycelia. This work was also intended to develop a simple mathematical formula to calculate decolorization (%) of various dye categories usually tested on the solid medium plate involving different white rot fungi. The fungus was grown on malt extract agar (MEA) plate containing media supplemented with CR, 1% (g/l) to check the extent of decolorization and hence efficacy of Resinicium bicolor laccase at an interval of 24 hours (hrs). Decolorization (%) was determined by a formula derived from ‘Plate Volume Method’ (PVM). The maximum decolorization achieved on solid medium was 97.79% and 96.79% in liquid culture medium by the end of 96 hrs without the involvement of any chemical mediators which are generally toxic and expensive. Efficient decolorization achieved in the liquid medium validated the accuracy of ‘PVM’.

Orange-derived and lemon-derived adsorbents with controlled grain for an efficient elimination of some cationic and anionic dyes

Purpose This study aims to demonstrate that orange-derived and lemon-derived systems can be used in continuous processes as efficient adsorbents to the entrapment of some anionic and cationic dyes in the textile dyeing wastewater effluents. Design/methodology/approach Physically and chemically modified orange and lemon mesocarps are used as natural adsorbents for the cationic dyes Basic Blue 3, Basic Yellow 21, Basic Red 18 and Basic Green 4 and the anionic dyes Acid Blue 264, Acid Yellow 49 and Acid Red 337, all commonly used in the textile dyeing industry. Adsorption capacities of the orange-derived and lemon-derived adsorbents on the dyes are studied simulating a batch and continuous industrial processes. Findings Results demonstrate that treated orange mesocarp (orange-derived adsorbent) can adsorb up to 97% of cationic Basic Green 4 in 30 min, whereas the lemon mesocarp (lemon-derived adsorbent) can retain up to 88% within the same time. In the case of anionic, 91% Acid Blue 264 is adsorbed by the orange mesocarp in 15 min, whereas 92% is adsorbed by the lemon homologue within the same time. Originality/value As far as the authors know, physically and chemically modified orange and lemon mesocarps have not been used on the removal of cationic (Basic Blue 3, Basic Yellow 21, Basic Red 18 and Basic Green 4) and anioinic (Acid Blue 264, Acid Yellow 49 and Acid Red 337) dyes of textile dyeing wastewater industry. It is a costless and efficient treatment that supposes, on the one hand, an eco-friendly and feasible process for discolouration of wastewater and, on the other, a valorisation (upcycling) of orange and lemon peels, which are not currently used.

Treatability of Wastewater Containing Reactive Yellow 145 Dyestuff by Ozonation Process

When the textile industry wastewater volume and considering the composition appears to be one of the most environmentally hazardous industries. Due to the basic properties of textile dyeing industry wastewater, additional precaution are required besides conventional wastewater treatment to remove color. The most basic approach is to remove the color of the wastewater and to break down the chromophores and double bonds that make up the color by oxidative means. In this study, the treatability of wastewater containing Reactive Yellow 145 (RY 145) dyestuff by ozonation process has been investigated. The initial concentration of the wastewater containing RY 145 is 50 mg / L. In the study, pH, O3 dose and reaction time parameters have been studied in RY 145 dye removal. The most appropriate removal of RY 145 from wastewater have occured at pH 5, 0.05 g / L.sa O3 dose and 10 minutes reaction time. The removal efficiency of RY 145 has obtained as 99.07% under optimum conditions.

Combination of wet fixation and drying treatments to improve dye fixation onto spray-dyed cotton fabric

The conventional dyeing process requires a substantial amount of auxiliaries and water, which leaches hazardous colored effluents to the environment. Herein, a newly developed sustainable spray dyeing system has been proposed for cotton fabric in the presence of reactive dyes, which has the potential to minimize the textile dyeing industries environmental impact in terms of water consumption and save significant energy. The results suggest that fresh dye solution can be mixed with an alkali solution before spray dyeing to avoid the reactive dye hydrolysis phenomenon. After that, drying at 60–100 °C, wet fixation treating for 1–6 min, and combined treatments (wet fixation + drying) were sequentially investigated and then dye fixation percentages were around 63–65%, 52–70%, and above 80%, respectively. Following this, fixation conditions were optimized using L16 orthogonal designs, including wet fixation time, temperature, dye concentration, and pH with four levels where the “larger-the-better” function was selected to maximize the dye fixation rate. Additionally, the color uniformity and wash and rubbing fastnesses were at an acceptable level when both treatments were applied. Finally, the dyes were hydrolyzed after wet fixation, and the hydrolysis percentages were enhanced after the drying process.

Studies On the Role of Fungal Strains in Bioremediation of Dyes Isolated from Textile Effluents

Fungal strains are widely used for the cleaning of soil, sediments, groundwater, surface water, and theecosystem. The presence of extracellular enzymes in fungi facilitates the process of bioremediation of textile dyes. Thisstudy was conducted to observe the quality of water being released from textile dyes industries and also the capabilityof some fungal strains which can remediate these dyes by showing the tendency of their resistance. Samples of waterwere collected from the polluted area surrounding the textile dyeing industries in Lahore. In the process of isolation,Potato Dextrose Agar (PDA) medium was used to verify the fungal growth. Fungal strains were purified, and themorphological characterization of fungal strains was carried out at 10X and 100X by using a magnification microscope.The fungal strains, such as Aspergillus niger, Aspergillusoryzae, and Aspergillusflavus were identified. The stress offour types of dyes was given to each fungal strain. The results showed that Aspergillusoryzae was one of the moststable, non-toxic, and resistant fungal species against the high stress of dyes as compared to other species.

Carbon Nano Particles as better Adsorbent against Photocatalytic Degrader for the Rhodamine - B Dye

Paper industries will be using a different kind of dyes for producing various kinds of paper. Rhodamine–B (Rh-B) dye is one of the major sources of color effluents from textile and paper dyeing industries, and they cause long-term effects for on an aquatic environment. So this work mainly focused on the synthesis of carbon nanoparticles from neem leaves, characterization and its adsorption and photocatalytic action against Rh-B dye. In this study, Carbon nanoparticles (C NPs) from neem leaves were synthesized for adsorption and photo catalytic degradation of Rh-B dye used in paper industries. The synthesized carbon NPs were characterized by the powder X-Ray Diffraction and Scanning Electron Microscopy. The adsorption and photocatalytic properties of Ccarbon NPs were examined for 1 hour by studying the degradation of the Rh-B dye at every 5 minutes time interval through UV-Visible spectrophotometer. The results obtained shown that carbonC NPs acts as better adsorbents than as photo catalysts.

Application of TiO2/ZnFe2O4/glycine nanocatalyst to the treatment of methyl orange dye from aqueous solution: Impacts of dissolved mineral salts on dye removal efficiency

This study aimed to remove one of the frequently used dyes in textile industries, Methyl Orange, from pollutant water with TiO2/ZnFe2O4/Glycine nanocatalyst under UV irradiation. The TiO2/Glycine/ZnFe2O4 nanocatalyst was synthesized through the sol-gel method and characterized by XRD, XRF, FT-IR, UV-Visible DRS, BET, FE-SEM, and EDX analyses. Process factors, including initial dye concentration (10-30 ppm), nanocatalyst dosage (0.5-1.5 g/L), initial pH solution (3-11), and irradiation time (30-150 min), were investigated by central composite design. The removal efficiency of Methyl Orange was 80% under optimal conditions (dye concentration: 20 ppm, nanocatalyst dosage: 1 g/L, irradiation time: 120 min, and pH=6.5). The effects of mineral salts such as NaHCO3, NaCl, Na2SO4, KCl, MgSO4, and CaCl2 with the concentrations of 50-800 ppm on the dye removal efficiency were examined under the optimal conditions. Low concentrations of NaCl, KCl, and CaCl2 had adverse effects on MO removal efficiency, while the dye removal efficiency raised at their high levels (RNaCl.800=74.52%). An increase in concentrations of MgSO4 and Na2SO4 led to deactivation effects on the dye removal efficiency and reaction rate constant (MgSO4 deactivation: 36%). There was an upward trend in the pollutant removal efficiency and reaction rate constant using NaHCO3 (RNaHCO3.800=82.4% and kNaHCO3.800=20.84 day-1).

Eradication of Fatal Textile Industrial Dyes by Wastewater Treatment

Dyes are typically existing in trace masses in the preserved wastes of numerous manufactures. The adsorption efficiency for dye elimination from unwanted water bodies has made it a perfect substitute to further exclusive usage procedures. The emission holding the poisonous cationic dyes from the textile industries is an intimidating issue today due to ecological ratifications and their opposing effect on human biology. Dyes removes from the industrial wastewater overflows effectually detached by consuming adsorbent, such as stimulated carbon, though its price limits large-measure submissions. The removal of dyes from the water is very important in demand to diminish the toxic effects on nature.

Removal and degradation of mixed dye pollutants by integrated adsorption-photocatalysis technique using 2-D MoS2/TiO2 nanocomposite

Two-dimensional (2D) Molybdenum disulfide (MoS2) has become one of the most exciting areas of research for adsorbents due to its high surface area and abundant active sites. Mainly, 2D MoS2 show promising removal of textile dye pollutants by adsorption process, but it show high affinity for anionic type of dyes, that limits its performance in mixed dye pollutants treatment. Herein, we demonstrate an integrated approach to remove mixed dye pollutants (anionic and cationic) concurrently by combining adsorption and photocatalysis process. We synthesize MoS2/TiO2 nanocomposites for different weight percentages 2.5, 5, 10, 20, 30 and 50 wt% of pre-synthesized flower-like MoS2 nanoparticle by a two-step hydrothermal method. We demonstrate a new process of two-stage adsorption/photocatalysis using high wt% of MoS2 (Stage-I) and low wt% of MoS2 (Stage-II) nanocomposites. The proposed two-stage integrated adsorption and photocatalysis process using 50% and 2.5% of MoS2 coated TiO2, respectively showed complete removal of methylene blue dye ∼5 times faster than conventional single-stage (adsorption or photocatalysis) water treatment process. Furthermore, the feasibility of the proposed two-stage method in mixed dye pollutants removal (anionic and cationic) testified, which showed excellent performance even in doubling the dye pollutant concentration. This work brings a deeper insight into understanding the morphology and concentration of 2-D MoS2 in MoS2/TiO2 nanocomposite in tackling mixed dye pollutants and the possibilities of applying in textile dyeing industries wastewater treatment plants.

Chlorophenols in textile dyeing sludge: Pollution characteristics and environmental risk control

Chlorophenols (CPs) are toxic contaminants that tend to accumulate in textile dyeing sludge and pose a threat to the environment through the disposal process. To comprehensively evaluate CPs in sludge, the characteristics and risks of CPs from five textile dyeing plants (TDPs) were investigated in this study. The total concentration of 19 CPs (Σ19 CPs) varied from 170.90 to 6290.30 ng g−1 dry weight (dw), among which high-chlorine phenols accounted for the greatest proportion. The ecological screening level (ESL) of CPs was used to judge their pollution levels, while the risk quotient (RQ) value and dioxin conversion rate were used to analyze their potential risk. The results indicated that CPs may pose a moderate to high risk to the environment. The Fenton process was used to condition the hazardous sludge, and a higher content of CPs was found after conditioning. A lower rate of CP increase was achieved with a reagent dose of 180 mmol/L, H2O2:Fe2+ = 1:1, pH of 3–4 and reaction time of 30 min. In summary, the work helps to address the general knowledge gap in the textile dyeing industry and provides a reference for further research.

Persistent organic and inorganic pollutants in the effluents from the textile dyeing industries: Ecotoxicology appraisal via a battery of biotests

Today, the textile industry is considered as a leading economic sector in Tunisia. However, this sector demands a huge volume of water and a wide spectrum of chemicals, which is converted into potentially toxic wastewater leading to environmental perturbation and human health toxicity. Assessment of the environmental risks associated with textile wastewater becomes a necessity. In this study, textile dyeing wastewater samples were collected before and after the physico-chemical treatment carried out by textile companies located in Monastir-city-Tunisia and subjected to chemical analyzes in order to determine their physicochemical characteristics and the content of metals and textile dyes. The ecotoxicological assessment was performed using four organisms, namely Selenastrum capricornutum, Vibrio fischeri, Daphnia magna and Lepidium sativum, to represent different trophic levels. Based on chemical data, some physicochemical parameters (e.g. TSS, COD and TSS levels) and metals (e.g. Cr, Hg and Sb) in the textile dyeing effluents were revealed not in compliance with the Tunisian standard. Moreover, high quantities of three disperse dyes have been detected even in the textile dyeing wastewater samples before and after treatments. The ecotoxicological data confirmed that the textile dyeing influents displayed toxic effects to all the test organisms, with Selenastrum capricornutum being the most sensitive organism. While, the above toxic effects were decreased slightly when evaluating the treated effluents. Metals and textile disperse dyes could be associated with the observed toxic effects of the textile influents and effluents. In fact, the treatment process applied by the evaluated companies was only partially efficient at removing metals, disperse dyes and effluent ecotoxicity, suggesting potential risks to aquatic biota. These findings emphasize the importance of applying integrated chemical and biological approaches for continuous evaluation of the toxicity of the treated effluents to predict hazards on the environment.

Immobilization of laccase from Bacillus subtilisDS on chitosan beads and standardization of process for biodegradation of textile dyes

AbstractBACKGROUNDThe textile industry generates a huge amount of effluents containing different hazardous dyes. Indigo carmine and malachite green are the most commonly used dyes in textile and dye industries. Pollution caused by these dyes affects aquatic life.RESULTSBacillus subtilis DS produces an alkali‐thermostable laccase. This enzyme was immobilized on chitosan beads and conditions for immobilization were optimized. After immobilization, the maximum activity of 26 IU g–1 beads was found under optimized conditions of 1% glutaraldehyde, 3 h cross‐linking time and 5 h immobilization time. The immobilized enzyme retained a temperature and pH profile similar to that of the free enzyme. Significant enzyme activity was retained after ten reaction cycles with >60% stability after 15 days, allowed reuse of enzyme over multiple cycles. Immobilized laccase was used to degrade textile dyes and the conditions were standardized statistically for its optimal degradation. Under optimized conditions a high degradation rate was achieved for indigo carmine (95.24%) and malachite green (90%), respectively.CONCLUSIONImmobilized laccase is a highly suitable candidate for bioremediation of textile industry dyes because of its stability and reusability. © 2021 Society of Chemical Industry

Absorption of Remazol Red dye from textile waste using activated carbon from coconut shell

The use of dyes in textile industry has great potential in polluting the environment, particularly due to the remaining dyes in wastewater are very difficult to decompose naturally. This pollution can be reduced by conducting special treatment on textile waste to decrease the dyes level. One of the most popular is the adsorption method. The purpose of this research was to study the adsorption of Remazol Red dye in textile waste by activated carbon synthesized from coconut shell. Activated carbon was given two different treatments: without activation and with activation at 900 °C. The results showed that the activated carbon synthesized had water content of 22.52% (without activation) and 9.49% (with activation). The adsorption of these activated carbons against Remazol Red dye took place optimally at the contact time of 30 minutes by following the Langmuir adsorption isotherm model. The adsorption process occurs homogeneously with the formation of monolayer with a qm value (maximum monolayer capacity) of 226.2 mg/g (without activation) and 250 mg/g (with activation).

Bio Efficacy Assay of Laccase Isolated and Characterized from Trichoderma viride in Biodegradation of Low Density Polyethylene (LDPE) and Textile Industrial Effluent Dyes

This study is based on the biosynthesis of laccase enzyme from fungi Trichoderma viride and its exploitation in biodegradation of polyethylene using Laccase mediator system (LMS -Laccase + 1-HBT) in Low Density Polyethylene (LDPE) and in biodegradation of textile industrial effluent dyes. In different parts of our lifespan we have seen the numerous types of plastics are getting degraded by various methods, still the average time to completely degrade a plastic bottle is at least 450 years.Similarly industry produces over 3.6 thousand individual textile dyes today and utilizes more than 8000 toxic chemicals in numerous methods for textile manufacture comprising dyeing and printing. As polyethylene and textile industrial effluent dyes are causing severe hazardous effect on environment and health issues in all kind of living organisms, it is necessary to degrade plastics and textile industrial effluent dyes in rapid way. Recently researchers have come up with an idea of degrading plastic and textile industrial effluent dyes with the help of microorganisms and enzymes much faster than normal rate. The Laccase enzyme extracted was tested for its optimum temperature and pH. Lowry’s method is used for protein estimation. A control and sample LDPE was subjected to LMS. The tensile strength and elongation of the sample was less than that of the control after 5 days of treatment. This study showed that laccase together with 1-HBT helps to biodegrade polyethylene. The purified laccase enzyme was used for the pretreatment assay and post treatment assay. The Laccase degrades certain reactive dyes like Congo red, Acid Red, Methylene Blue, Brilliant Blue, Metallic Blue and Black. Thus recommends the application of laccase in textile dye colour removal (bioremediation).

Eco-friendly colorization of textile originating from polydopamine nanofilm structural color with high colorfastness

Traditional textile dyeing industry usually use chemical pigments and dyes, which bring about a large amount of colored wastewater causing serious environmental pollution. Replacing the traditional high pollution dyeing methods to realize eco-friendly dyeing is very important to the textile dyeing industry, structural colorization maybe one of the most promising methods. In this study, a novel approach was proposed to fabricate eco-friendly coloration of textile originating from polydopamine (PDA) structural color nanofilm with high colorfastness. Four different bright colors were obtained by the polymerization of PDA nanofilm with different reaction times on cotton fabric. However, capillary tension during the formation of PDA nanofilm and weak interaction with fabric substrate resulted in cracking and poor colorfastness. The novel synthesis adhesive of poly (glycidyl methacrylate co-polyethylene glycol methyl ether methacrylate) containing reactive epoxy groups was used to avoid cracking and improve the colorfastness which would form covalent bond on the interface between structural color film and substrate. Therefore, crack-free PDA structural color nanofilm with high colorfastness on cotton fabric surface was obtained. This facile approach provide novel idea for eco-friendly dyeing different kinds of textiles with structural color boosting the cleaner dyeing in textile industrial field.

Durable and chemical resistant ultra-permeable nanofiltration membrane for the separation of textile wastewater

It is highly challenging to prepare durable and chemical resistant ultra-permeable membranes that can quickly separate small organic molecules like dye or inorganic salt in the complex textile wastewater industry. Here, side-chain sulfonated poly(ether ether ketone) (SPEEK) was synthesized and prepared the poly(ether ether ketone) (PEEK) - SPEEK nanofiltration (NF) membrane by a simple dipping coating and heat treatment. Single component filtration tests of the optimized membrane showed ultrahigh pure water flux (126 Lm−2 h−1 bar−1) and relatively low NaCl rejection (6.7%). Moreover, the negatively charged membrane exhibited excellent rejection of 98.8% toward Congo red (CR). The pure water flux was about 9 folds than that of commercial NF270 with comparable solutes rejection. The separation tests of CR and NaCl mixed solution at optimized conditions exhibited ultra-high permeation flux (34 Lm−2 h−1 bar−1), satisfactory dye (98.8%)/salt (< 10%) rejection and the separation performance remained stable after 10 cycles. Finally, the contaminated membrane was washed with ethanol, the permeation flux and the CR rejection remained constant after several cycles, while the commercial NF1 membrane exhibited serious swelling only within one cycle. The prepared membrane exhibited good organic solvents resistance and antifouling properties. Thus, this work confirmed the PEEK-SPEEK NF membrane showed great potential in the sustainable treatment of textile wastewater.

Review and New Evidence on the Molluscan Purple Pigment Used in the Early Late Bronze Age Aegean Wall Paintings

The production and use of the pigment extracted from the murex molluscs is discussed here in association with the purple textile dyeing industry in the Prehistoric Aegean. “True” purple has been identified in a number of archaeological finds dating from the early Late Bronze Age, found in old and recent excavations at three different but contemporary sites: Akrotiri and Raos on Thera, and Trianda on Rhodes. The chemical composition of the shellfish purple pigment either found in lump form or applied on wall paintings is discussed in relation to the archaeological context of several examined finds and with reference to Pliny’s purpurissum. The results of a comprehensive methodology combining new data obtained with molecular spectroscopies (microRaman and FTIR) and already reported data obtained with high performance liquid chromatography coupled with a diode array detector (HPLC–DAD) applied to samples of the murex purple finds are discussed in comparison to published data relating to few other instances of analytically proven murex purple pigment found in the Aegean over the timespan of its documented exploitation.

Long-Term Exposure to Azo Dyes from Textile Wastewater Causes the Abundance of Saccharibacteria Population

Discharge of untreated wastewater is one of the major problems in various countries. The use of azo dyes in textile industries are one of the key xenobiotic compounds which effect both soil and water ecosystems and result in drastic effect on the microbial communities. Orathupalayam dam, which is constructed over Noyyal river in Tamil Nadu, India has become a sink of wastewater from the nearby textile industries. The present study had aimed to characterize the bacterial diversity and community profiles of soil collected from the vicinity of the dam (DS) and allied agricultural field (ALS) nearby the catchment area. The soil dehydrogenase and cellulase activities were significantly lower in DS compared to ALS. Additionally, the long-term exposure to azo dye compounds resulted in higher relative abundance of Saccharibacteria (36.4%) which are important for degradation of azo dyes. On the other hand, the relative abundance of Proteobacteria (25.4%) were higher in ALS. Interestingly, the abundance of Saccharibacteria (15.2%) were also prominent in ALS suggesting that the azo compounds might have deposited in the agricultural field through irrigation. Hence, this study revealed the potential bacterial phyla which can be key drivers for designing viable technologies for degradation of xenobiotic dyes.

Impacts of natural and synthetic mordants on cotton knit fabric dyed with natural dye from onion skin in perspective of eco-friendly textile process

An important concern has been reached a growing interest in natural dyes in the textile dyeing industry for coloring fabrics due to growing environmental consciousness of preventing toxic synthetic dyes. Moreover, the use of metallic mordants does not make them entirely eco-friendly. Being aware of this, this report examines cotton knit fabric dyeing with natural mordants with dyes derived from onion skin executed using aqueous boiling technique. Diverse mordants, e.g., alum, ferrous sulphate, iron water, myrobalan, eucalyptus bark, and their combinations on cotton knit fabrics were used for pre-mordanting and together mordanting procedures. Several techniques and different types of equipment were used to measure various results. As a result, the mordanting techniques were reported to impact the outcomes of the dyeing procedure. That diverse mordants and mordanting techniques influenced the colour values produced a wide variety of gentle colors; thus, intermixing of natural and synthetic mordant gave the best result in together mordantation. Also, the pre-mordanting method gave averagely better results and dyeing properties than together mordanting, but eucalyptus gave the best results in together mordantation. Fading was found a little dissatisfactory in washing in case of natural mordants, yet staining properties were quite impressive. For other dyeing properties, satisfactory results were found for both natural and synthetic mordants. Their intermixing also contributed better results. Hence, it was evident that eucalyptus bark might be used as a suitable natural mordant for onion skin dyeing since eucalyptus showed the best result as an individual mordant or intermixing with synthetic mordant.