The desalting and recycling of wastewaters from textile dyeing operations using reverse osmosis

The wastewater from the textile dyeing operations was separated into a concentrate stream, rich in salts and dyes, and a purified product water stream using reverse osmosis membranes. Three membrane materials and three module configurations were used, namely : polyamide (hollow fine fiber configuration ), cellulose acetate ( spiral wound and tubular configurations ) and hydrous Zr(IV)- polyacrylate ( tubular configuration ). The modules were tested for periods ranging from 600 hours to more than 1000 hours under actual field conditions. Membrane flux and rejection were monitored throughout the operation and samples of the feed and product water were analysed chemically. The successful operation of the R.O. equipment under field conditions demonstrated the applicability of this process in the desalination of dyeing wastewater.     

Electrokinetic properties of textile fabrics

This paper reports electrokinetic phenomena concerning the properties of textile fabrics that are crucial for dyeing and finishing processes. These interface phenomena influence the adsorption of surfactants, optical brighteners, dyes and finishing agents due to interaction forces between the fibre surface and solution. Zeta potential, isoelectric point, point of zero charge and the amount of surface charge of standard adjacent fabrics (cotton, wool, viscose rayon, polyamide, polyester and acrylic) have been determined. Electrokinetic potential was measured by a method involving streaming potential/current using an electrokinetic analyser. The specific amount of surface charge was calculated by a back-titration method.     

Determining the effect of enzymatic pretreatment on the low temperature dyeability of polyamide fabrics

In this study, by pretreating polyamide 6/elastane knitted fabrics with serine-type protease enzyme, the aim was to reduce dyeing temperatures. It is known that the elasticity of elastane fibres is damaged in dyeing at high temperatures. On the other hand, to enable efficient dyeing, it is necessary to use boiling temperatures in synthetic fibres such as polyamide, or even mild high temperature conditions, to support more uniform dyeing. Protease enzymes are enzymes that hydrolyse amide bonds, and consequently, new amine and carboxyl groups are released in fibre macromolecules, resulting in an increase in the functional group content to which anionic dyes can bind. In this study, to compensate for the loss of colour yield caused by lowering the dyeing temperature, an increase in the functional groups was provided by enzymatic pretreatment. For this purpose, the fabrics were pretreated with a commercial serine-type protease enzyme then dyed with 1:2 metal complex dyes at different temperatures. The effects of enzymatic pretreatment on colour, fastness, fibre surface characteristics and fabric strength were investigated.     

Decolorising textile effluents

Amendments to the legislation on waste water are making the legal requirements for textile waste water more stringent. In addition to the limits on the metal content and the COD and AOX values, restrictions are also being placed on the colour of the effluent. Anionic dyes (e.g. reactive dyes and metal-complex acid dyes) are removed from spent dye liquors by means of ion pair extraction by long-chain amines. The effect of pH and the structure of the amine has been studied. In reactive dyeing such treatment reduces both the amount of colour and the AOX value. In the case of the metal-complex dyes the removal of the (chelated) metal is of prime importance. The metal-complex dyes can be recovered from the organic phase by extraction with caustic soda and then re-employed in dyeing. The amines that result at the end of dye recovery are practically colourless and may be reused.     

锦纶66微纤维活性染料染色条件探讨

采用毛用和棉用活性染料对锦纶66微纤维染色,详细讨论了染色温度、染浴pH值、染色和皂洗方法对染色深度和固色率的影响,分析了不同类型的活性染料对染色条件的敏感性。活性染料对锦纶66微纤维的染色深度、固着率和固着效率受温度、pH值、染料母体结构和活性基的影响很大。毛用活性染料更适合于锦纶66微纤维的染色,普通乙烯砜硫酸酯及乙烯砜硫酸酯/一氯均三嗪染料可有选择性地加以使用,毛用活性染料合适的染色pH值约为4,其它染料适用的pH值因品种而异。采用酸性染色或先酸性后碱性的染色条件均可,后者的优点是固着效率高,但染色深度未见提高染色后采用碱性条件皂洗有利于染色深度的提高。     

生物能纤维针织面料的染色工艺

采用高温高压的染色方法,通过分散染料上染生物能纤维针织面料,对影响其染色性能的助剂用量、染液pH值、升温速率、固色时间这4个主要因素进行单因素分析,并采用正交试验的方法对其染色工艺进行优化,最后通过对染色色牢度进行评定,得出上染生物能纤维针织面料的最佳染色工艺。     

适用于纺织荧光染色的染料及其应用研究进展

荧光染料凭借发射强度高、色彩鲜艳、荧光强烈等特点，在纺织领域吸引了许多染料专家们的目光，是一类非常具有应用前景的功能性染料。该文按染料结构分类的方式综述了从上世纪至今商品化分散、酸性和活性荧光染料以及新型1, 8-萘酰亚胺类、香豆素类、半花菁类和其它类新型荧光染料及其衍生物在纺织染色领域的研究进展，最后提出适用于纺织荧光染色的染料在纺织领域未来的发展趋势。     

Pigments extracted from the wood‐staining fungi Chlorociboria aeruginosa,Scytalidium cuboideum,and S. ganodermophthorum show potential for use as textile dyes

A growing interest in the use of naturally produced pigments for textile dyeing has led to increased efforts towards the identification of such pigments that are less toxic, more sustainable, and more stable over time than currently used synthetic compounds. This work utilised various concentrations of green, red, and yellow pigments extracted with dichloromethane from the wood‐staining fungi Chlorociboria aeruginosa, Scytalidium cuboideum, and S. ganodermophthorum, respectively, for the effective dyeing of bleached cotton, spun polyamide (nylon 6.6), spun polyester (Dacron 54), spun polyacrylic, and worsted wool. All three pigments utilised in this study show significant potential for use as textile dyes. Colour changes suggested that drip application methods were superior to submersion using dichloromethane. Colour changes as compared with the untreated fabrics were most significant on polyester, which is likely due to increased levels of polymer swelling in polyester exposed to dichloromethane.     

Cathodic decolourisation of textile waste water containing reactive dyes using a multi‐cathode electrolyser

The reductive decolourisation of textile dyestuffs containing an azo group was investigated by direct cathodic electron transfer CI Acid Red 27 and CI Acid Yellow 9 were used as model compounds for azo dyes. Reactive dyes, eg CI Reactive Red 4, CI Reactive Orange 4, and CI Reactive Black 5, which are in technical use for cellulose dyeing were investigated as representatives of practical importance. A basic characterisation of the reduction–decolourisation behaviour of the dyes was achieved by redox titration with Fe(II)–triethanolamine as reducing agent and parallel spectrophotometric observation of changes in the chromogenic system. From the redox titration experiments basic data describing the experimental conditions for successful cathodic electron transfer can be derived. The electrochemical dyestuff reduction experiments were performed in batch trials using a multi‐cathode electrolyser with high cathode area. According to the typical composition of such dyebaths 0.12 mol dm^?3 NaOH was used as ground electrolyte. The absorbance of the investigated dyestuff solutions could be decreased to below 20% of the initial value. For a 50% decrease in absorbance, electrical energy of about 6 kWh m^?3 is consumed. The process is of particular interest for the treatment of concentrated dyestuff solutions as they are used in continuous dyeing processes. © 2001 Society of Chemical Industry     

Application of cyclodextrin to the textile dyeing and washing processes

Cyclodextrins can form inclusion complexes with different molecules with the aid of their special chemical (molecular) structures. Physical and chemical properties of molecules can change after the formation of complex. This special feature enables the usage of dextrins in different industry areas. In this study, applicability of cylcodextrins in textile dyeing and washing processes was investigated. With this aim, β‐cyclodextrin was used in direct dyeing of cellulosic fabrics and in rinsing processes of direct dyed fabrics. Retarder/leveling effect of β‐cyclodextrin in dyeing process has been studied and the results were compared with that of a commercial product. In general, cyclodextrins were used in washing processes to remove the absorbed surfactants. It has been investigated whether this effect was the same for washing of dyed fabrics. Eight different direct dyes, for which the chemical structures are known, were used in dyeing and washing processes, and effect of β‐cyclodextrin on different chemical structures was investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 208–218, 2006     

大豆/PTT微胶囊分散染料/活性染料一浴一步法染色

探讨了纯碱和氯化钠用量、染料浓度对微胶囊分散蓝2BLN/活性染料(活性蓝KN-R、活性深蓝B-2GLN和活性蓝K-3RL)一浴法染色大豆/PTT混纺织物表观色深K/S值的影响,测定了不同染色工艺对染色织物牢度的影响.结果表明:当染料总用量为2％(o.w.f.),纯碱用量1g/L,氯化钠用量20 g/L,95℃条件下保温30分钟时,可使大豆/PTT混纺织物获得较高的表观色深.     

Studies on the possibility of recycling microencapsulated disperse dye‐bath effluents

The volume of water consumed by human beings has increased dramatically in recent years while water supply has remained constant; both demographic growth and the expansion of industrial activity require more water consumption. The textile industry is undoubtedly one of the most pressured industries that need water intensively. Efficient use of water tends to be a crucial subject for the dyeing industry. In this study, melamine resin microcapsules containing pure disperse dyes were prepared by in situ polymerization. The microcapsules were characterized on the basis of structure, morphologies, mean particle size, and size distribution. The dyeing behaviors of microencapsulated disperse dyes (MDDs) were evaluated on polyester fabrics in the absence of auxiliaries. Its effluent can be reused several times after being simply filtered and can be used as solvent for PET fabric scouring. The treated fabrics exhibited satisfactory levelness and fastness properties. MDDs can be used in dyeing PET, without using surfactants, and the effluents can be recycled and reused. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

光子晶体结构色纺织材料的制备及应用研究进展

为解决当前纺织印染行业大量使用高污染、高能耗且易褪色的传统化学染料和颜料的问题,针对结构生色材料所具有的不含着色剂、颜色鲜艳、不易褪色等特点,本文综述了近年来光子晶体结构色纺织材料的制备及应用研究进展。介绍了光子晶体结构及其结构生色机理,阐述了结构色纺织材料常用的制备方法,着重归纳了光子晶体结构色在纤维、纱线、织物及颜料等方面的应用,并分析了其在应用过程中存在的问题。分析表明,光子晶体结构色纺织材料已经可以达到大面积快速制备,且在织物上构筑结构色较为方便且研究较多,在纱线上构筑结构色的研究较少,在纤维上构筑结构色容易赋予其功能性且相关研究逐渐增多。最后总结了光子晶体结构色应用于纺织领域所存在的问题,并对该研究方向进行了展望。     

The dyeing of nylon with a microencapsulated disperse dye

Melamine resin microcapsules containing CI Disperse Blue 56 were prepared by in situ polymerisation. The microcapsules were characterised by their thermal properties and morphology, such as particle size and particle size distribution. The dyeing behaviour of the microcapsules on nylon 6.6 was evaluated. The microencapsulated dye exhibited good build-up, levelness and fastness properties. It has been demonstrated that microencapsulated disperse dye can be used to replace commercial disperse dyes in dyeing polyamide fabric without dyeing additives, and the resulting effluent can be easily recycled after filtration.     

Investigation into the dyeing of wool with Lanasol and Remazol reactive dyes in seawater

Freshwater is an increasingly scarce resource that is extensively used in textile wet‐processing. In seeking to identify alternative low freshwater‐usage coloration technology, this study examined the potential use of seawater (SEAW) as the dyeing medium for wool coloration using a range of reactive dyes. Initially, the dyeing behaviour of the wool fabric in simulated seawater (SSW) was compared with conventional dyeing from distilled water (DW) using α‐bromoacrylamide‐based Lanasol dyes and sulphatoethyl sulphone‐based Remazol dyes. These preliminary studies demonstrated that comparable coloration could be achieved in the SSW medium based on an assessment of the dye exhaustion, dye fixation, colour yield and levelness. Subsequent dyeing studies of wool using Mauritian seawater with both the Lanasol and Remazol reactive dyes confirmed that, based on the dye exhaustion, dye fixation, colour yield and levelness, comparable coloration could be achieved, highlighting the possibility of substituting freshwater with seawater as the dyeing medium.     

One‐step dyeing of polyethylene terephthalate fabric,combining pretreatment and dyeing using alkali‐stable disperse dyes

In the conventional dyeing process, polyester and its blended fabrics are usually dyed in a weak acidic medium. In order to reduce cost and improve production efficiency, a new dyeing method – one‐step dyeing of polyethylene terephthalate fabrics, combining pretreatment and dyeing in alkali conditions – was investigated. The alkali‐stable disperse dyes Red 900, Red 902, Yellow BROB and Blue 825 were used to dye polyethylene terephthalate fabrics. The dyeing properties of polyethylene terephthalate fabrics in the case of one‐step dyeing at various pH values or sodium hydroxide concentrations were discussed in terms of colour yield, colour parameters and fastness. The performance of one‐step dyeing using alkali‐stable disperse dyes was excellent. The dyed fabric had good fastness. Wet processing could be combined and shortened. One‐step dyeing of polyethylene terephthalate fabrics could reduce the consumption of water and energy and improve production efficiency. One‐step dyeing of polyethylene terephthalate has potential application in cleaner textile production.     

Investigation and feed-forward neural network-based estimation of dyeing properties of air plasma treated wool fabric dyed with natural dye obtained from Hibiscus sabdariffa

In the colouring processes of textile products, more environmentally friendly chemicals and finishing methods should be used instead of conventional ones that harm the environment every day, so that alternative realistic ways to protect nature, both academically and industrially, could be possible. Due to some inconveniences caused by synthetic dyes that are widely used today, in this study, ultrasonic dyeing of wool fabric with Hibiscus sabdariffa was carried out after environmental-friendly air vacuum plasma application which increased the absorption of the dyes into the textile material. According to the performance results, colour strengths of the wool fabrics were increased significantly. Surface morphology analysis was carried out and etching effects of air vacuum plasma treatment were clearly seen on the micrographs of the treated wool fabrics. An environmental-friendly green process was achieved through this study and it was concluded that vacuum air plasma treatment could be an alternative green-process as a pretreatment to increase the dye up-take of natural dyeing treatment. Moreover, in this study, a feed-forward neural network (FFNN) model was presented and used for predicting the dyeing properties (L, a, b and K/S) of samples. The experimental results showed that the presented model achieves the regression values greater than 0.9 for all dyeing properties. Consequently, it was considered that the proposed FFNN was successfully modelled and could be efficiently utilised for dyeing characteristics of wool fabrics dyed with natural dye extracted from Hibiscus sabdariffa.     

A novel and eco-friendly approach for dyeing polyester fabrics by liquid disperse dyes treated with deep eutectic solvent

Disperse dyes do not contain water-soluble groups and are difficult to dissolve in water, so they cannot be directly formulated into dyeing liquor. In the current dyeing process, the solubility of disperse dyes is mainly improved by adding dispersants. However, dispersants are not absorbed by fibres and survive in the dyeing effluent, aggravating the pollution of water bodies and causing difficulties in treatment. Therefore, the development of a novel, eco-friendly dyeing approach is important to overcome these problems. Herein, for the purpose of improving the solubility of disperse dyes and reducing the dosage of dispersants, a deep eutectic solvent consisting of choline chloride/ethylene glycol was employed instead of dispersant to dissolve CI Disperse Blue 79 and CI Disperse Red 343, thus forming liquid disperse dyes. The results show that both CI Disperse Blue 79 and CI Disperse Red 343 were well dissolved in choline chloride/ethylene glycol with excellent stability, and the dissolution behaviour was strongly associated with the dissolution temperature and time. Moreover, polyester fabrics can be dyed successfully with liquid disperse dyes, and it was observed that the K/S value and rubbing fastness were evidently improved at the same dyeing temperature with unchanged colour characteristics, and a higher K/S value could still be obtained by lowering the dyeing temperature. This work establishes a green dyeing process, which reduces dyeing costs and meets the demand for environmental protection. It is also expected to realise the liquid state of disperse dyes, which will help to promote the further development of textile dyeing.     

Studies on quinoline type dyes and their characterisation studies on acrylic fabric

Nitrogen heterocyclic fluorescent compounds and their possible dyeing pathway on acrylic fabrics was investigated. Their chemical spectral properties, including fluorescence and ultraviolet–visibility, were evaluated in this work. The colour fastness properties of these dyes attributable to light reflection and washing were examined. The CIE L*, a* and b* values after the dyeing process were studied and the colour fastness properties were also determined. Two quinoline derivatives showed stronger fluorescence properties and were also demonstrated to be non‐cytotoxic towards human HaCaT skin keratinocytes at a reasonable dose. These results led to speculation that these two compounds could be further used as dyes in various textile applications.     

Extraction,identification and sorption studies of dyes from madder on wool

Since the last decade, the application of natural dyes on textile materials is gaining popularity all over the world, possibly because of increasing awareness of environment, ecology, and pollution control. In this research, extraction of dyes from madder at different conditions has been studied. The extracted dyes from madder were examined by TLC and HPLC. The adsorption properties of the dyes extracted from madder on natural polyamide fibers (wool) were also determined. The rate of dyeing at different temperatures, as well as the values of standard affinity, entropy, and enthalpy was calculated. The results indicated that increase of temperature leads to decrease the values of partition ratio and affinity. The adsorption isotherm was tested by fitting the adsorption data with Langmuir, Freundlich, BET, and Temkin isotherms. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009