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Introduction
Published in Ram Lakhan Singh, Pradeep Kumar Singh, Rajat Pratap Singh, Recent Advances in Decolorization and Degradation of Dyes in Textile Effluent by Biological Approaches, 2019
Ram Lakhan Singh, Pradeep Kumar Singh, Rajat Pratap Singh
Synthetic dyes are generally water soluble or water dispersible colored organic compounds which are widely used for imparting color to various substrates such as textiles. These dyes are capable of absorbing the light in the visible region (400–700 nm). The chromophore group of dye molecules is responsible for the absorption of light. Dyes can be obtained from natural sources or manufactured artificially. The first synthetic dye, Mauveine, was synthesized by Perkin which was made up from coal tar. Dyes may be classified in a number of ways, according to their chemical structure, color or industrial application (Table 1.1). The classification of all commercial textile dyes has been compiled in the Color Index (CI) which is published by the Society of Dyers and Colourists (United Kingdom) in association with the American Association of Textile Chemists and Colorists (AATCC) (Clark 2011). Table 1.2 shows the chromophore group and structural formula of some textile dyes.
Dyeing and Recent Developments
Published in Asis Patnaik, Sweta Patnaik, Fibres to Smart Textiles, 2019
Prithwiraj Mal, Debojyoti Ganguly
Dyeing is an important phenomenon for value addition of textile products. The customers are attracted towards the textile materials due to colours. From the prehistoric times the art of dyeing was developed. At that time, different types of natural dyes were used abundantly for the coloration of available natural fibres like linen, cotton, wool, and silk. These dyes were extracted from different plants, insects, minerals, etc. Fabric was dyed by soaking it in the aqueous extraction and then dried. After the advent of synthetic dyes, they accounted 90% of the total uses of dyestuff. Presently, most of the industries use synthetic dyes due to their great availability, higher reproducibility of the shade, better fastness properties, wide colour gamut and more colour values with high affinity for the colour. Now, natural dyes are mainly used by craft persons for small-scale production. Application of dyestuff on textile materials is a complicated phenomenon, where visual aesthetics of the products are improved with the application of creativity, science and technology. Chemistry of the dyes and the application of dyestuffs are very complex processes, but with the invention of different sophisticated machines, computer colour matching systems, good qualities of synthetic dyes and other chemical auxiliaries, the process of dyeing has become universal.
Symplocos Paniculata (Sapphire Berry): A Woody And Energy-Efficient Oil Plant
Published in Megh R. Goyal, Susmitha S. Nambuthiri, Richard Koech, Technological Interventions in Management of Irrigated Agriculture, 2018
Qiang Liu, Youping Sun, Jingzheng Chen, Peiwang Li, Genhua Niu, Changzhu Li, Lijuan Jiang
Natural dyes originated from plant materials are a sustainable source of colorants. In contrast to the hazardous effects of synthetic dyes on skin such as allergy, skin cancer, etching, rashes, and so on13 and severe water and atmospheric pollution resulting from non-degradable byproducts, natural dyes are non-toxic, biodegradable, and ecologically safe. To meet the demand of green chemistry and the use of safer chemicals to minimize the pollution for environmental considerations, the cultivation of dye plants and the development of novel natural dyes have recently drawn considerable attentions. A yellow dye is obtained from its rough yellowish-brown and corky bark.8 Badoni and Semwal2 conducted a study to apply the dye extracted from S. paniculata leaves and bark on white cotton thread and cloth, particularly to compare the affinity of vegetable mordents (Euomymus tingens bark extracts and Myrica esculenta leaf extracts) and common synthetic mordents (copper sulfate and stannous chloride) with fiber. They concluded that S. paniculata (leaves and bark) dyed with natural mordents (extracts from E. tingens bark extracts and M. esculenta leaf) produce different color hues with better fastness properties than that of synthetic mordents (CuSO4⋅5H2O and SnCl2⋅2H2O).
Application of biorefinery by-product of Nigella sativa L. herb for green treatment of synthetic dye impurity in aquatic environment: a circular economy based approach to water purification
Published in International Journal of Phytoremediation, 2023
Water, which is one of the most precious materials for the existence and healthy continuation of living life, is polluted day by day with human intervention and becomes more unusable. Among the major types of contaminants that create serious pressure on water, the synthetic-based dyes constitute one of the most important global issues today. The synthetic dyes are commonly used chemical compounds in various industrial areas like mainly the textile, food, paper, leather, and plastic industries to color the products. Mostly because of the low fixation rate of synthetic dyes, the industrial effluents contain large amounts of these chemicals and are often discharged into the receiving water environment without adequate treatment. The synthetic dyes decrease the clarity and oxygen solubility of water, increase the chemical/biological oxygen demand, and spoil the appearance of water. They limit the photosynthetic activity of organisms by reducing the penetration of sunlight into aquatic environment. In addition, many of the synthetic dyes and their degradation products have accumulative, allergic, toxic, mutagenic, and carcinogenic effects causing various diseases and even death on human and other living beings (Hassan and Carr 2018; Pavithra et al.2019; Zhou et al.2019; Sarkar and Dey 2021). Therefore, it is vital that these dangerous compounds are effectively removed from aqueous medium, even if they are present in very low concentrations.
Treatment of Leather Dyeing Wastewater with Associated Process of Coagulation-Flocculation/Adsorption/Ozonation
Published in Ozone: Science & Engineering, 2018
Bianca Mella, Brunna Samuel de Carvalho Barcellos, Dimitrius Extralazon da Silva Costa, Mariliz Gutterres
Dye molecules comprise of two key components: the chromophores, responsible for producing the color, and the auxochromes, not only which can supplement the chromophore but can also render the molecule soluble in water and give enhanced affinity (to attach) toward the fibers (Hunger 2003). Azo dyes are most used in tanneries, because they provide high intensity and bright color. They have in their chemical structure the azo group (–N = N–) linkage, which is attached to aromatic ring systems, that under anaerobic conditions can be reduced to aromatic amines that are toxic and carcinogenic compounds (Yagub et al. 2014). When compared with natural dyes, synthetic dyes have advantages of low cost, a vast range of colors, easy product coloration, and great lightfast stability (Sha et al. 2016).
Application of waste Camellia oleifera fruit shell for printing on PP nonwoven
Published in The Journal of The Textile Institute, 2021
Monthon Nakpathom, Buppha Somboon, Nootsara Narumol, Rattanaphol Mongkholrattanasit
Negative environmental impacts of synthetic dyes have aroused extensive interest in the use of natural colorants during the last few decades. Besides textile dyeing, certain natural dyes have been applied by printing technique as mentioned in previous works, for example, alkanet and rhubarb (Rekaby et al., 2009), red mangrove bark (Nakpathom et al., 2011), eucalyptus leaves and bark (Ellams et al., 2014), turmeric, madder, and rhubarb (Maamoun et al., 2014), catechu, turmeric, and marigold (Teli et al., 2014), annatto seed, manjistha root, and ratnajot bark (Chattopadhyay & Pan, 2019). In our earlier study, the printing pastes were prepared from an aqueous solution extracted from Camellia oleifera fruit shell with commercial thickener and binder and then screen printed on cotton fabric (Nakpathom et al., 2017). Pre- or post-mordanting with aluminum potassium sulfate, copper sulfate, and ferrous sulfate controlled the final color shades and color fastness properties. The obtained prints had various shades ranging from yellowish brown to brownish grey with fair to good color fastness to washing, light, crocking and perspiration. All of the above natural dye printing researches were made on traditional woven fabrics from cotton, wool, silk, linen, and jute. Therefore, in order to investigate this application on new textile substrate, the present work further studies the possibility of using natural colorant powder extracted from Camellia oleifera fruit shell for printing on PP nonwoven. The influences of varying amounts of natural extract, ferrous sulfate mordant, and binder on color strength, color fastness and basic mechanical properties are also examined.