1 Sustainable Dyeing Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
P. Senthil Kumar and P. R. Yaashikaa
2 Eco-friendly Production Methods in Textile Wet Processes . . . . . . . 31
Seyda Eyupoglu and Nigar Merdan
3 Sustainability in Wastewater Treatment in Textiles Sector . . . . . . . . 67
P. Senthil Kumar and A. Saravanan
Sustainable Dyeing Techniques
Abstract The success of textile industry depends on the colour of the finished product which attracts humans. Textile industry often deals with design and conversion of yarn into fibre then into fabric finally dyed and fabricated into finished clothing. Dyeing is defined as the method of imparting colour to finished products mainly fabrics or during the initial stage to the yarn itself. Three main processes are involved in dyeing process namely preparation, dyeing and finishing. Dyeing process may be carried out in batch or in continuous mode. It consists of a special solution containing dye and chemical for binding. The two factors influencing dyeing process are temperature and time controlling. There are different methods applied by textile industries for adding colour to the products. Few dyeing techniques include exhaust, pad, pad-fixation, printing, bale, batik, beam, chain, cross, random, etc. Though dyes are attractive in nature, their impact on environment depends on the type of substance used and removal and degradation of dye substances. The contaminated wastewater discharged out after dyeing process contains huge amount of chemical substances which has negative impact on environment.
Keywords Textile industry · Dyeing process · Dyeing techniques Degradation · Dyeing machines
The textile industry is primarily examined about the plan and creation of yarn, fabric, apparel, and their dispatch. The crude material might be regular, or engineered utilizing the outcomes of other industries usually chemical. Textile industry is a standout amongst the most water-concentrated sectors. The effluent from textile industry is portrayed by high chemical oxygen demand (COD), biological oxygen demand (BOD), total dissolved solids (TDS) and pH. While yarn is for the most part created in the factories, textures are delivered in the power loom and handloom segments also. Ecological issues relatedwith the textile industry are commonly those related with water contamination. Characteristic contaminations removed from the fibre being prepared alongside the chemicals utilized for handling are the two fundamental wellsprings of contamination . Effluents released from textile industry are hot, basic, strong odour and coloured by chemicals which are used as a part of colouring process. A portion of the chemicals released are lethal. The main process of textile industry relays on the change of fibre into yarn, yarn into texture which are then coloured or printed and created into garments. Distinctive sorts of fibre are utilized to create yarn. Cotton remains the most imperative normal fibre, so is dealt with top to bottom. There are numerous variable procedures accessible at the turning and texture framing stages combined with the complexities of the completing and colouration procedures to the creation of wide scopes of outcomes. There remains a large scale industry that utilizes hand systems to accomplish similar outcomes .
The textile industry can be classified into two major divisions based on their development as composed and sloppy textile industries. Composed textile industries is an exceptionally sorted out one with enormous significance on the capital concentrated generation process. This segment is described by refined plants where innovatively propelled apparatus are used for large scale manufacturing of textile materials. Sloppy Textile Industry segment is the predominant piece of this industry which for the most part uses the conventional practices woven or spun in fabric creation and consequently is work concentrated in nature. This industry is described by the creation of garments either through weaving or turning with the assistance of hands. The decentralized nature is considered as another critical element of the sloppy textile industry in India .
Globalization is unpreventable and necessary under the present world financial circumstance. Numerous ventures are influenced decidedly or adversely by the globalization drift. There is no exception for the textile industry from this case. It has been confronting an emergency circumstance in a previous couple of years. It confronts an extreme rivalry on the global advertise. Indian textile industry is one of the biggest and the most vital areas in the economy as far as yield, outside trade profit, and business eras. India has likewise been a huge player in the worldwide textile markets. It is the third biggest maker of cotton, second biggest maker of silk, the biggest maker of jute and the fifth biggest maker of man-made strands and yarn. The Indian Textile Industry, being one of the most seasoned and critical divisions gains a great deal of remote trade and utilizes an impressive level of the community from both rural and urban ranges. Cotton exports have developed as a noteworthy wellspring of outside trade winning for the country. Indian Textile industry has been seeing amajor basic change, persistently re-evaluating and rediscovering it to address the issues of the worldwide consumers. Indian Companies have begun raising their benchmarks and furthermore forcefully seeking their human asset methodologies . The overall dyeing process of textile industry is shown in Fig. 1.
2 Dye and Its Importance
Dyes might be characterized as substances that, when connected to a substrate give shading by a procedure that adjusts, in any event briefly, any gem structure of the hued substances. Such substances with impressive dyeing limit are broadly utilized in the textile industry, pharmaceutical, nourishment, cosmetics, plastics, photographic, etc. The colours can hold fast to perfect surfaces by arrangement, by framing covalent bond or forming complexes with metallic salts, through the process of physical adsorption or by mechanical maintenance. The textile industry expands a generous measure of water in its assembling forms utilized for the most part in the colouring and completing or finishing operations. The wastewater from textile industrial plants is named the most dirtying of all the mechanical segments, considering the quantity created and in addition, the composition of effluents released. Likewise, the expanded interest for textile outcomes and the corresponding increment in their generation, and the utilization of manufactured colours have together added to dye wastewater getting to be plainly one of the generous wellsprings of extreme contamination issues in at times. A standout amongst the most troublesome assignments defined by the wastewater treatment plants of the textile industry is the evacuation of the shade of these mixes, principally in light of the fact that colours and shades are intended to oppose biodegradation, with the end goal that they stay on the earth for a drawn out stretch of time. The colouring procedure is one of the key factors in the effective exchanging of textile outcomes . The buyer typically searches for some essential item attributes, for example, great obsession regarding light, sweat, and washing, both at first and after delayed utilize. To guarantee these properties, the substances that offer to shade to the fibre must demonstrate a high resemblance, even shading, imperviousness to vanishing and be financially possible. Present day dyeing innovation comprises of a few stages chose by the idea of the fibre and properties of the colours and shades for use in textures, for example, chemical structure, arrangement, product accessibility, financial contemplations, etc. Colouring techniques have not changed much with time. Essentially, water is utilized to clean, colour and spread other chemicals to the textures, and furthermore to wash the treated fibres or textures. The fibres utilized as a part of the textile industry can be classified into two fundamental gatherings designated natural and synthetic fibres. Common Natural fibres are gotten from the earth plants or creatures, for example, fleece, cotton, flax, silk, jute, and sisal, the majority of which depend on cellulose and proteins. Then again, engineered or synthetic fibres are natural or organic polymers, generally got from oil sources, for instance, polyester, polyamide, rayon, etc. The two most significant materials in the textile industry are cotton, the biggest, and polyester .