Reusing wastewater of madder natural dye for wool dyeing

Natural dye is environment-friendly which is usually extracted from vegetative material. In this work, the wastewater of madder dyebath is reused for wool dyeing. Initially, the madder absorption behavior on wool fiber is determined by new methods based on spectroscopic information of dye solution. The absorbance spectra change is explained in terms of absorbability of chemical components of madder on wool by using several techniques such as principal component analysis, colorimetry, statistical and derivative spectroscopy techniques. The obtained results indicate that the chemical components of the initial dye solution are different from those remaining in the exhausted dye solution. In reusing wastewater of wool dyeing with madder, the exhausted dyebath is reconstructed by adding madder and water. The analyzing color parameter and fastness properties of samples indicate that the quality of samples dyed in reconstructed dyebath is the same as initial wool dyeing. The economic analysis shows that the reusing wastewater caused 19.91% cost saving in wool dyeing with madder.     

Eco-friendly dyeing of wool using natural dye from weld as co-partner with synthetic dye

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 weld using soxhlet apparatus has been studied. The color components extracted and isolated from weld plant were characterized by Column Chromatography, Thin Layer Chromatography (TLC), NMR, mass, IR techniques. The natural dye extract obtained from the weld was used for the dyeing of wool fiber. The results indicated that the exhaustion rate for the extracted dye increases by 49% compared to the raw dye. This, in turn, leads to a considerable decrease in the amount of the extracted dye used to reach the same desired results. Finally, for comparative studies between synthetic and this natural dye, all dyed specimens were tested for wash and light fastness properties, making weld a viable alternative to synthetic acid dyes.     

Optimization of alkaline extraction of natural dye from Henna leaves and its dyeing on cotton by exhaust method

The alkaline conditions for extraction of natural dye from Henna leaves were optimized and the resulting extract was used to further optimize its dyeing conditions on cotton by exhaust method. Dyeings without any mordant were compared with those obtained with premordanting and postmordanting with alum and iron. It was found that dyeings produced with alkaline extracts of Henna leaves have better colour strength than the dye extracts obtained in distilled water. Furthermore, dyeings with alkaline extracts have moderate to good fastness properties and that mordanting did not result in any significant improvement in fastness properties. Finally, in comparative studies between synthetic and this natural dye, it was inferred that natural dye has good potential to act as co-partner with synthetic dye.     

Using supercritical carbon dioxide as solvent to replace water in polyethylene terephthalate (PET) fabric dyeing procedures

Dyeing fabrics in supercritical carbon dioxide (SCD) instead of water can save energy, reduce water use and prevent pollution. The special pilot plant was designed to test dyeing procedures in supercritical carbon dioxide and the analyses of the results indicate major benefits as compared to water based procedures. The dyeing of polyethylene terephthalate (PET) fabric in supercritical carbon dioxide using special pilot plant was investigated. Disperse dye, C.I. (color index) Disperse Blue 79, was used in this study. After dyeing, rinsing in supercritical carbon dioxide, which removes the excess dyes, was also discussed. At the same dyeing conditions, K/S (color yield) of dyed fabric significantly increased with increasing the dye concentration from 1% o.w.f. (on weight of fabric) to 5% o.w.f. Dyeing temperature and pressure had a strong influence on the color yield. When the temperature rose above 110 °C, the increase in color yield was obvious. At 20 MPa, 120–130 °C, dyeing reached equilibrium after 60 min. The excess dye of the dyed PET fabric was small. The suitable condition in supercritical carbon dioxide for removal of excess dye from the dyed fabric was 70 °C, 20 MPa. The PET fabric dyed in supercritical carbon dioxide had good fastness and physical properties.     

Assessment of antimicrobial activity of Catechu and its dyed substrate

The present study was undertaken to evaluate the antimicrobial activity of catechu in solution and % microbial reduction of dyed wool samples against Escherichia coli MTCC 443, Staphylococcus aureus MTCC 902, Candida albicans ATCC 10261 and Candida tropicalis ATCC 750, by using micro-broth dilution method, disc diffusion assay and growth curve studies. The dye showed the maximum antimicrobial activity at 20% w/v, inhibiting the microbial growth by more than 90%. In the next set of the experiments the antimicrobial activity of the dye was compared on woollen yarn alone and on pre-mordanted samples. The reduction in antimicrobial activity was observed when mordanted samples were examined. K/S, CIELab values and fastness properties of the dyed samples were assessed. The structural morphology of woollen yarn was also evaluated using scanning electron microscopy (SEM). Haemolytic activity on human erythrocytes was studied to exclude possibility of further associated cytotoxicity. The observed antimicrobial characteristics and negligible cytoxicity of catechu indicate that the dye might be a promising antimicrobial agent for developing bioactive textile materials and clothing.     

不同弹性体对电子废弃物废PP改性效果的影响

针对废PP(聚丙烯)的抗冲击强度降幅明显的问题,分别采用POE(乙烯-辛烯共聚物)和SBS(苯乙烯-丁二烯-苯乙烯嵌段共聚物)作为增韧剂,对废PP共混改性效果进行了研究. 结果表明:POE和SBS均可有效改善废PP的韧性,提高冲击强度;当弹性体用量为15%(以w计,下同)左右时,其共混体系的冲击变化过程由脆性断裂逐渐向韧性断裂转变;添加16.7%的弹性体时,POE和SBS共混体系的冲击强度可分别达到新PP的2.33和1.90倍,但POE对共混体系的冲击性能改善效果更佳. POE较SBS在废PP基体中分布更为均匀,弹性体用量为16.7%时,PP/POE体系熔体流动速率为17.4g/10min,大于PP/SBS体系(6.21g/10min),即PP/POE体系具有加工优势. 但是添加弹性体后,废PP共混体系的拉伸强度、弯曲强度等指标有所下降,需进一步提高.      

Alcohol-assisted dyeing processes: a chemical substitution study

Dyeing processes of various yarns (wool, cotton, polyester, nylon 6 and acrylic) were studied with the aim to substitute some auxiliary agents with ethanol at low concentration. The results observed in isothermal dyeing showed a favorable effect of alcohol addition, at about 1-3% v/v, on the dye uptake, with some differences depending on fiber nature and dye class. This effect was correlated with contact angle measurements of water-ethanol solutions on the mentioned yarns, which confirmed a lower surface tension in the same concentration range. Then, laboratory tests with dye triads at programmed temperature were carried out comparing the results of standard dyeing recipes with those obtained by replacing wetting, retardant and leveling agents with ethanol. Good color imitations were generally shown with respect to standard processes. A wetting effect of ethanol was shown for all the tested yarns and dye classes, while in wool dyeing with acid, pre-metallized and reactive dyes, ethanol was suitable to replace also leveling and retarding agents. Light and wash fastnesses were also compared. Finally the environmental benefits arising from chemical substitution of auxiliary agents with ethanol were highlighted and the cost of alcohol introduction was compared with the cost saving of auxiliary substitution. A positive economic balance was obtained.     

Micelle dyeing with low liquor ratio for reactive dyes using dialkyl maleic acid ester surfactants

Micelle dyeing with low liquor ratio is novel fabric dyeing method for cleaner production. Preparation and interaction of dye-surfactant micelles using dibutyl maleic acid ester sodium sulfate surfactant were investigated by UV-Vis spectra. Dyeing properties of cellulose fabrics using micelle dyeing with low liquor ratio were discussed by color yields (K/S), color differences (ΔE), exhaustion (E), fixation (F) and reactivity (R) of three reactive dyes. The results show that reactive dye molecules could be solved in surfactant micelles and form stable dye-surfactant micelles. Micelles formed by dibutyl maleic acid ester sodium sulfate had good anti-agglomeration effect on dye solutions. Liquor ratio of micelle dyeing for cellulose fabrics could be reduced from 1:15 to 1:5. Leveling properties of three reactive dyes using micelle dyeing were good. The exhaustion, fixation and reactivity of all three dyes using micelle dyeing were similar with the conventional dyeing technology. Wet rubbing, washing and perspiration fastnesses of dyed samples using micelle dyeing were also good. Micelle dyeing with low liquor ratio can save a large amount of water and energy.     

碱性阴离子交换纤维处理印染废水的研究

采用自制的弱碱性阴离子交换纤维处理含活性染料的印染废水,研究了该方法的处理效果及其影响因素。结果表明:弱碱性阴离子交换纤维处理含活性染料的印染废水有良好的效果,接枝率为70%～80%的离子交换纤维处理效果最佳。离子交换纤维用量、pH、反应温度和反应时间对处理效果有重要影响。初步探讨了离子交换纤维的脱色机理。     

Colourimetric analysis and antimicrobial study of natural dyes and dyed silk

Colourimetric and antimicrobial activities of natural colourants and dyed silk have been studied. The colour strength (K/S) values were increased with increase in dye absorbance. The absorption of dyes on silk yarns was obtained from 10.56 to 39.48% at 5% concentration of dye from different plant extracts. The colourimetric parameters L¹, a¹, b¹, C, and H were measured for depth of the colour. The dyed silk with natural colourants displayed excellent antimicrobial activity (reduction rate: 25–65%) against the bacteria Escherichia coli and (reduction rate: 3–68%) against the fungal strain Aspergillus niger. The dyed silk exhibited good and durable fastness properties.     

Natural dyes in modern textile dyehouses — how to combine experiences of two centuries to meet the demands of the future?

Plant materials which are available from farming regions in the moderate Austrian climate were investigated to serve as sources for natural dyes in textile dyeing operations. The extraction of the dye components from the plant materials was performed with boiling water without addition of chemicals or solvents. Based upon a rigorous selection of possible plant sources, a selection of natural dyestuffs applicable in a one-bath dyeing step was established. A broad variation in shade and color depth can be achieved by applying mixtures of natural dyestuffs in various combinations of iron- and alum-mordants. More than 60% of tested dyeings achieved acceptable fastness properties.On the basis of the developed natural dyestuff-based dyeing procedures, a comparison was made between the effluents from processes based upon them and those based upon the current ‘state-of-the-art’ techniques utilizing synthetic dyes. The comparison revealed that a lowering of the chemical load released with waste water can be expected by shifting to the plant-based dyes.     

印染废水吸附处理研究现状

随着染料纺织工业迅速发展,产生的印染废水成了水系环境的主要污染源之一,而染料品种的日益增加,及产品结构和印染工艺的不断改变,使得印染废水的水质也发生了变化,处理难度也随之加大。本文主要介绍不同的吸附处理法的优缺点及它们对不同污染因素的吸附效率。通过对几类吸附方法的比较,发现新兴的秸秆纤维素类生物吸附剂,既可以有效的解决农业固体废弃物的处理问题,又能低成本高效率的处理印染废水,对我国建立发展可持续发展,环境友好型社会具有重要的意义。     

有机-无机共聚高分子混凝剂在活性染料印染废水治理中的应用

在对某以活性染料为主要染料的棉、丝针织物染整厂废水处理工程技术改造过程中,将有机-无机共聚高分子混凝剂辅以少量的PAC代替石灰乳和硫酸亚铁,稳定运行后连续6周取数据进行分析,结果表明,技改后当进水COD为350~520 mg/L,色度为650~1200倍时,出水COD<90 mg/L,色度30倍左右,污泥产量只有原系统的1/2,且运行费用比原系统低。     

Ozone treatment of Angora rabbit fiber

The aim of this study was to investigate a novel bleaching technique for Angora rabbit fiber. For this purpose, a detailed investigation on the role of the fiber moisture, pH, and treatment time during ozonation was carried out. Also, the effect of ozonation on the dyeing properties of Angora rabbit fibers was researched. Consequently, it was found that ozonation improved the degree of whiteness and dyeability of Angora rabbit fiber.     

用高压脉冲放电等离子体处理印染废水的研究

提出了用高压毫微秒脉冲产生的非平衡等离子体处理印染废水的方法。用该法对直接蓝２Ｂ染料水溶液进行处理试验的结果表明：在溶液初始pH值于小9.04,染料水溶液处理30秒时,水样上清液COD降低42.6％。随着处理时间的加长,水样上清液的COD不再降低,反而不断升高,在处理一定时间后,COD高于未处理水样的COD。包括沉淀水样的COD,随处理时间的加长,不断升高．用色质联用法检测处理后染料溶液中的产物,发现有有机酸生成,说明该处理方法能有效破坏染料分子中的苯环或苯环结构。     

Electrochemical reduction in vat dyeing: greener chemistry replaces traditional processes

In application of vat dyes the substitution of non-regenerable reducing agents such as Na₂S₂O₄ by cathodically regenerable reducing agents offers great ecological advantages. In a demonstration project a 45 A multi-cathode electrolyser successfully was coupled to a dyeing apparatus for package dyeing with a capacity of 1–10 kg material. Iron-complexes with triethanolamine and Na-d-gluconate were used as cathodically regenerable reducing agents. Dyebath regeneration was performed by ultrafiltration. Substantial reduction in chemical consumption and reduction in wastewater volume, released from the dyeing process could be demonstrated. Quality of dyeings was assessed with regard to levelness and iron content analysed in the dyed samples.     

Surface modification of polypropylene non-woven fibers with TiO2 nanoparticles via layer-by-layer self assembly method: Preparation and photocatalytic activity

Polypropylene (PP) meltblown fibers were coated with titanium dioxide (TiO₂) nanoparticles using layer-by-layer (LbL) deposition technique. The fibers were first modified with 3 layers of poly(4-styrenesulfonic acid) (PSS) and poly(diallyl-dimethylammonium chloride) (PDADMAC) to improve the anchoring of the TiO₂ nanoparticle clusters. PDADMAC, which is positively charged, was then used as counter polyelectrolyte in tandem with anionic TiO₂ nanoparticles to construct TiO₂/PDADMAC bilayer in the LbL fashion. The number of deposited TiO₂/PDADMAC layers was varied from 1 to 7 bilayer, and could be used to adjust TiO₂ loading. The LbL technique showed higher TiO₂ loading efficiency than the impregnation approach. The modified fibers were tested for their photocatalytic activity against a model dye, Methylene Blue (MB). Results showed that the TiO₂ modified fibers exhibited excellent photocatalytic activity efficiency similar to that of TiO₂ powder dispersed in solution. The deposition of TiO₂ 3 bilayer on the PP substrate was sufficient to produce nanocomposite fibers that could bleach the MB solution in less than 4 hr. TiO₂-LbL constructions also preserved TiO₂ adhesion on substrate surface after 1 cycle of photocatalytic test. Successive photocatalytic test showed decline in MB reduction rate with loss of TiO₂ particles from the substrate outer surface. However, even in the third cycle, the TiO₂ modified fibers are still moderately effective as it could remove more than 95% of MB after 8 hr of treatment.     

原料材质、产品类型及生产工序对印染废水产生特性的影响研究

选取嘉兴市82家印染企业,针对棉、毛、化纤3种典型原材料,研究了织物、纱线、纤维产品在前处理、染色和印花等工段的废水产生量和水质,基于产污强度算法估算了各印染工序的废水产污强度.结果表明：棉、毛、化纤织物印染废水总产生强度分别为90.21、206.02、109.66 L·kg^-1织物,漂洗为废水主要产生工序.印染各工段化学需氧量（COD）产生强度普遍较高,特别是棉、化纤织物前处理工段COD产生强度高达136.98和131.67 g·kg^-1织物.印染部分工序氮、磷产污强度高,如棉、毛、化纤织物的洗网废水总氮（TN）产生强度为4.98、1.25、2.21 g·kg^-1织物,棉纤维、毛织物和毛纱线的染色工序总磷（TP）产生强度为0.28、0.18、0.18 g·kg^-1产品,还有棉、化纤的洗网废水TP产生强度为0.30、0.15 g·kg^-1产品.利用产污强度及治理设施削减系数估算得出的印染企业各废水污染物排放量,与污染物在线监测数据相比较,相对误差低于30%;将本研究所得各产污强度与第二次全国污染源普查产污系数比较,除印花工段外,两者相对偏差均低于20%.本研究获得的印染行业各产污节点特征和产污强度,可为印染行业的环境精细化管理和产污节点管控提供数据支撑.     

液相高压放电降解RB5染料废水的试验研究

随着印染工艺不断更新,大量化学分子结构复杂的化工染料应用到印染行业,使得常规的水处理工艺难以降解印染废水中的染料。本文以活性黑（RB5）染料为研究对象,采用液相高压放电产生强氧化性自由基来降解染料废水,考察反应时间、初始浓度和气体流量对RB5降解的影响,研究结果表明：在外部功率相同的情况下,浓度高染料其降解率相对较低;通入氧气量增加,产生的活性自由基和活性物质数量也增加,RB5的降解率也增大,但气流量不宜过大;高压放电产生的各种活性物质容易破坏染料发色基团的分子链,使其脱色。     

Natural dyeing of wool and hair with indigo carmine (C.I. Natural Blue 2), a renewable resource based blue dye

Indigo carmine can be used as a source of blue dye for wool and hair dyeing. The option to use indigo carmine in combination with other natural dyes in a one-bath procedure as a hybrid dyeing concept is of interest both for natural dyeing and for coloration of hair. The present study shows that indigo carmine dyeing on wool exhibits the substantial sorption in the range of pH 4–5 and temperature between 40 and 60 °C. Experiments with human hair samples indicate that the experiments on wool can serve as a model that can be applied for hair dyeing. Comparisons of the energy, water and chemical consumption between two-bath dyeing with indigo and natural dyes separately and a one-bath dyeing using indigo carmine together with other natural dyes demonstrates the advantages of the one-bath hybrid dyeing concept.