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Based on clarifying the structural difference between jade fibre and general polyester fibre, this paper aims to study the dyeing properties and dyeing adsorption mechanism of jade fibre with disperse dye and cationic dye.

The chemical structure and microstructure of jade fibre were briefly explained comparing with ordinary polyester fibre. The dyeing rate curve and dyeing adsorption isotherm of disperse dyes and cationic dyes on jade fibre were, respectively, studied. The dyeing uptake, dyeing absorption mechanism, and the main dyeing process parameters were proposed.

Jade fibre can be dyed with cationic dye and disperse dye. The suitable exhaust dyeing process is 110°C and 40 minutes for disperse dye, 100°C and 60 minutes for cationic dye. The dyeing uptake on jade fibre with both disperse dyes or cationic dyes is much higher than that on general polyester fibre and acrylic fibre, and the dyeing adsorption mechanism belongs to the combination of Langmuir and Nernst adsorption for disperse dyes and Langmuir adsorption for cationic dyes. Comparing with ordinary polyester fibre, jade fibre has the advantage of low temperature dyeing and reduced effluent, as is significant to energy-saving and emission reduction.

Jade fibre is a new type of modified polyester fibre with the function of health protection and energy conservation. There are little technical data in the literature at present about the dyeing property of jade fibre.

The purpose of this paper is to investigate the possible application of recycled wool‐based nonwoven material (RWNM) for removal of different dyes that are used in textile dye houses.

The sorption kinetics, the influence of initial dye concentration, pH and temperature are analyzed. Basic, reactive, direct and metal complex dyes are studied.

The sorption properties are highly influenced by the type of the dye owing to differences in their chemical structure and thus, the mechanism of binding to wool. Modification of material with chitosan and hydrogen peroxide improves the sorption capacities and sorption rates but no general trend can be established. Consequently, the sorption behaviour is analyzed separately for each type of the dye.

The results indicate that RWNM can be used as an efficient, low‐cost sorbent for decolorisation of effluents.

The purpose of this paper is to evaluate the efficacy and kinetics along with diffusion properties of a new source of natural dye obtained from leaves and fine stems of the Sesbania aculeata plant, using metallic mordants for cotton dyeing.

The approach followed in this work is to conduct experiments with the application of the natural dye obtained from Sesbania aculeata plant and to study the kinetics, dye uptake and the diffusion properties of this dye.

Sesbania aculeata with simultaneous mordanting with different metal mordants imparted shades which varied from cream to light brown to dark brown in case of aqueous extract. The different mordants used not only changed the hue colour and K/S values but also L* and brightness index values. The results of fastness properties of the dyes were found to vary from fair to good. The percentage dye exhaustion values varied with different mordants. The dye uptake value increased with time and reached its saturation limit after 4 hours of dyeing. In the absence of mordants, the diffusion coefficient values increased with increase in the temperature. In the presence of mordants, the diffusion process appears to slow down, which could be attributed to the binding effects of mordants.

The extraction and dyeing process of Sesbania aculeata plant is less tedious and time consuming compared to the other sources of natural dyes.

Sesbania aculeata is relatively easier to grow and does not require much tending operations. Thus, it promises to be an affordable source of natural dye. If this dye is commercialised, it will help to generate sustainable employment and income for the farmers in rural and sub-urban areas. This could be both for dyeing and for non-food crop farming.

An advantageous feature of this plant, in contrast to the other natural dyes based on vegetable and fruit sources, is that its usage in making the natural dye does not result in any wastage of an otherwise highly commercial product. The current experimental study on a new source of natural dye would be a significant contribution to the existing database of knowledge regarding the kinetics and diffusion properties of natural dyes. There are several reported studies in the literature pertaining to the application of natural colourants and evaluation of their dyeing properties on various fibers. However, relatively fewer studies exist on the kinetic and exhaustion aspects. Thus, the current study would help to develop a set of predictable settings for application of natural dyes on various textiles.

This paper aims to find a suitable solution to degrade the C.I. Reactive Red 24 (RR24) dyeing wastewater by using sodium persulphate to recycle water and inorganic salts.

The effects of temperature, the concentration of inorganic salts and Na₂CO₃ and the initial pH value on the degradation of RR24 were studied. Furthermore, the relationship between free radicals and RR24 degradation effect was investigated. Microscopic routes and mechanisms of dye degradation were further confirmed by testing the degradation karyoplasmic ratio of the product. The feasibility of the one-bath cyclic dyeing in the recycled dyeing wastewater was confirmed through the properties of dye utilization and color parameters.

The appropriate conditions were 0.3 g/L of sodium persulphate and treatment at 95°C for 30 min, which resulted in a decolorization rate of 98.4% for the dyeing wastewater. Acidic conditions are conducive to rapid degradation of dyes, while ·OH or SO₄⁻· have a destructive effect on dyes under alkaline conditions. In the early stage of degradation, ·OH played a major role in the degradation of dyes. For sustainable cyclic dyeing of RR24, inorganic salts were reused in this dyeing process and dye uptake increased with the times of cycles. After the fixation, some Na₂CO₃ may be converted to other salts, thereby increasing the dye uptake in subsequent cyclic staining. However, it has little impact on the dye exhaustion rate and color parameters of dyed fabrics.

The recommended technology not only reduces the quantity of dyeing wastewater but also enables the recycling of inorganic salts and water, which meets the requirements of sustainable development and clean production.

This study aims to show the dyeing behaviour of polyester fabrics using four novel heterocyclic disperse dyes.

The four dyes were synthesized based on 5, 5'-(1, 4-phenylene) bis (1, 3, 4-thiadiazol-2-amine) as a diazonium compound. The UV/Vis absorption spectroscopic data of these disperse dyes while dyeing polyester fabrics were investigated. Following this, the dyeing properties of these dyes on polyester fabrics were investigated under acid condition.

The results showed that increasing the dyeing temperature from 80°C to 100°C led to an increase in dye uptake for all dyes, but further increases of the temperature to 130°C led to higher dye uptake for dye 3 as the dye exhaustion increased by about 50% from 55.9% to 91.4%.

This study is important as it introduces new dyes for the dyeing of polyethylene terephthalate (PET) fibres with colours that range from yellowish orange to bluish yellow and scarlet red and all with excellent brightness, levelness and depth of shade.

The purpose of this study is to check the effectivity of plasma in the natural dyeing of polyester fabric using four natural dyes – Turkey red, Lac, Turmeric and Catechu using plasma and alum mordant. The surface modification on the polyester fabric by plasma along with the use of benign mordant alum is studied. The enhancement of dyeability in polyester fabric with natural dyes is the main focus. Due to surface modification, the wettability increases, which leads to better dye uptake. Better dye uptake and better dye adherence are the main objectives.

Plasma-mediated natural dyeing is the main design of this research work. The effect of plasma treatment on surface modification of synthetic fabric polyester and its subsequent effects on their dyeing with different natural dyes, namely, Turkey red, Lac, Turmeric and Catechu are studied. The dyeability was further enhanced by the use of alum as mordant. The main focus is on the betterment of natural dyeing of polyester fabric using sustainable natural dyes resources for dyeing and to reduce wastewater contamination from the usage of toxic additive chemicals for cleaner production.

Plasma-mediated and alum-mordanted dyeing method facilitated very good dyeability of all the four natural dyes, namely, Turkey red, Lac, Turmeric and Catechu. Color strength (K/S) values and fastness properties of plasma-treated samples were far better than untreated samples. The synergistic effect of plasma and alum mordanting has made natural dyeing of polyester very easy with very good fastness results. Natural dyeing of polyester after 2 min of plasma treatment showed excellent and desirable results. The process is also easy to be adapted by industries.

As polyester is hydrophobic, natural dyeing of polyester fabric is not very easy, but with plasma-mediated natural dyeing, it becomes a very facile dyeing method; thus, there are no limitations. Use of plasma has reduced the need for any chemical additives which are usually added during the dyeing process.

This process of natural dyeing of polyester fabric can be scaled up to industrial dyeing with natural dyes. Plasma pretreatment of the fabric followed by premordanting with alum has facilitated the natural dyeing well.

Use of plasma in place of chemical modifiers can be a green and environmentally friendly approach for sustainable coloration of polyester fabric, providing a clean wet processing for textiles dyeing.

The synergistic effect of plasma-mediated and alum-mordanted natural dyeing of polyester has not been attempted by any researcher. To the best of the authors’ knowledge, this is for the first time that pretreatment with atmospheric plasma followed by alum mordanting of polyester fabric has shown very good dye uptake and fastness properties as the dye molecules could penetrate well after 2 min of the plasma treatment.

The purpose of this paper is to evaluate the efficiency of ultrasonication on new natural dye obtained from leaves extract of Acer pectinatum Wallich using metal mordant for good cotton dyeing prospects.

For effective natural dyeing with leaves extract of Acer pectinatum Wallich, both conventional and sonication methods of dyeing were carried out using metal mordants. The purpose of using sonication was for improvement of dye uptake, improved dye adherence and good wash and light fastnesses. Results show marked improvement by the chosen dyeing method.

The superiority of sonicator dyeing over conventional dyeing in terms of enhanced resource productivity and, as a result, reduced wastes establishes it as the best available technique in the natural dyeing industry. Use of sonicator shows marked enhancement for cotton dyed fabric. Typical bath liquor to fabric ratio for conventional dyeing varies from 20:1 to 15:1 and for sonicator dyeing from only 12:1 to 10:1, thereby reducing specific water and energy consumption by, respectively, 30 and 50 per cent. The cycle time for dyeing was also reduced by 50 per cent and this would make possible more tonnage of fabric per unit time and lower waste generation for the dyeing process. This would also result in improved capacity utilisation leading to enhanced productivity levels in the dyehouses.

Although metal mordanting with copper sulphate and potassium dichromate is not ecofriendly, yet only 2 per cent of these metal salts have been used to prepare different shades with leaves extract of Acer pectinatum Wallich.

The method developed for natural dyeing of cotton fabric using sonication in conjunction with metal mordanting has shown marked improvement.

The method developed for natural dyeing of cotton fabric using sonication in conjunction with metal mordanting has shown marked improvement in terms of dye adherence and fastness properties and can thus be recommended for industrial application.

The purpose of this paper is to evaluate the dyeing potentials of Melastoma malabathricum whose fruit pulp showed high dye contents. It is an abundantly available shrub in the north eastern forests of India.

Dye extraction was carried out by conventional heating and sonicator. The dyebility of the aqueous extract of melastoma was evaluated for dyeing cotton fabric by two methods – sonication and conventional heating. The purpose of using sonication was for betterment of dye uptake, improved dye adherence and good wash and light fastnesses.

The test results showed that choosing this dyeing method produced improved results. The superiority of sonicator dyeing over conventional dyeing in terms of enhanced resource productivity and as a result, reduced wastes, makes it the established best available technique in the natural dyeing industry. Use of sonicator shows marked enhancement for cotton dyed fabric. Typical bath liquor to fabric ratio for conventional dyeing varies from 20:1 to 15:1 and for sonicator dyeing from only 12:1 to 10:1 thereby reducing specific water and energy consumption by, respectively, 30 and 50 percent.

Although natural dyeing has its limitations of fastness, we have tried to overcome this limitation by using sonicator.

The method developed for natural dyeing of cotton fabric using sonication in conjunction with metal mordanting has shown marked improvement.

The method developed for natural dyeing of cotton fabric using fruit pulp of Melastoma malabathricum under sonication in conjunction with metal mordanting using has shown marked improvement in terms of dye adherence and fastness properties and can thus be recommended for industrial application.

The purpose of this paper is to evaluate the efficiency of ultrasonication on new natural dye obtained from leaves and stem extracts of Daphne papyraceae using metal mordant for good cotton, silk and wool dyeing prospects. It also proposes to effect the characterisation of the colorant.

For effective natural dyeing with leaves and stem extracts of D. papyraceae, both conventional and sonication methods for cotton, silk and wool dyeing were carried out using metal mordants. The purpose of using sonication was for betterment of dye uptake, improved dye adherence and good wash and light fastnesses. Results show marked improvement by the chosen dyeing method. Simultaneously, chemical characterisation of the colorant was carried out by first column chromatographic separation of the crude extract, followed by spectral analysis of the isolated products.

The superiority of sonicator dyeing over conventional dyeing in terms of enhanced resource productivity and, as a result, reduced wastes makes it the established best available technique in the natural dyeing industry. This fact has been examined for several natural dyes. Use of sonicator shows marked enhancement for cotton‐, silk‐ and wool‐dyed fabrics. Typical bath liquor to fabric ratio for conventional dyeing varies from 20:1 to 15:1 and for sonicator dyeing from only 12:1 to 10:1, thereby reducing specific water and energy consumption by 30 and 50 per cent, respectively. The cycle time for dyeing was also reduced by 50 per cent and this would benefit the dyeing process with more tonnage of fabric per unit time and with lower waste generation. This would also result in improved capacity utilization leading to enhanced productivity levels in the dyeing houses.

Although metal mordanting with copper sulphate and potassium dichromate is not ecofriendly, only 2 per cent of these metal salts has been used to prepare different shades with leaves and stem extracts of D. papyraceae for cotton, silk and wool fabrics.

The method developed for natural dyeing of cotton, silk and wool fabrics using sonication in conjunction with metal mordanting has shown marked improvement. The chemical composition of the crude extract shows the presence of flavonoids and other specific natural pigments.

The method developed for natural dyeing of cotton, silk and wool fabrics using stem and leaves extracts of D. papyraceae under sonication in conjunction with metal mordanting has shown marked improvement in terms of dye adherence and fastness properties and can thus be recommended for industrial application. This is a new source of natural dye.

Replacing conventional mordants by benign mordants, rare earth (RE) salts have been used in the process of natural dyeing with annatto seed extract. The purpose was threefold – first, to increase the dye uptake through these new mordants; second, to have better fastness properties of dyed swatches and third, to have lesser effluent pollution, as the new RE mordants are used in one-tenth quantities only.

Sustainable natural dyeing was attained by using RE salts as mordant in one-tenth quantity, for natural dyeing, replacing the conventional mordants such as alum and ferrous sulphate. Annatto extract has been used as natural dye.

Through the study, it was inferred that the natural dyeing using annatto seed extract gives very good colour depth on the dyed swatches and also shows marked improvement in fastness properties.

Research implication is that often it is expected that any new chemical used in the textile processing adds on to the effluent load; however, contrary to that, this study found that the use of RE salt is very beneficial as it is used in smaller quantities, but gives far better dyeing results.

RE salts can be used in natural dyeing without causing any harm to the environment and dyers.

Use of RE salts in natural dyeing is a new concept. It is a very safe technology and can be used without causing any harm to the environment and the dyers.

This study is unique as it focuses on the use of RE salts in natural dyeing replacing the conventional mordants, which are used ten times more in quantity.