Characteristics of industrial textile effluents and different types of effluents


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Characteristics of industrial textile effluents and different types of effluents

  1. 1. Characteristics of industrial textile effluents and different type of dye materials used in textile industry Mithun Chouhan|10CH10026 Department of Chemical Engineering
  2. 2. Characteristics of textile effluents Diverse in Nature  Contain large variety of organic and inorganic materials used in • Degumming : is the process of removing the sericin, or silk gum, from silk. Removing the gum improves the sheen, color, hand, and texture of the silk. Because the gum can serve as a protective layer, it is typically left on the silk until it is ready to dye.
  3. 3. • Desizing: irrespective of what the desizing agent is, involves impregnation of the fabric with the desizing agent, allowing the desizing agent to degrade or solubilize the size material, and finally to wash out the degradation products. • Scouring: is the first process carried out in textile bleaching with or without chemicals, at room tempera-
  4. 4. • -ture or at suitable higher temperatures with the addition of suitable wetting agents, alkali and so on. Scouring removes all the waxes, pectins and makes the textile material hydrophilic or water absorbent. • Bleaching: The next process of decolorization of greige material into a suitable material for next processing is called bleaching.
  5. 5. • Dyeing: is the process of adding colour to textile products like fibers, yarns, and fabrics. Dyeing is normally done in a special solution containing dyes and particular chemical material. • Printing: is the process of applying colour to fabric in definite patterns or designs. In properly printed fabrics the colour is bonded with the fiber, so as to resist washing and friction.
  6. 6. Finishing: processes that convert the woven or knitted cloth into a usable material and more specifically to any process performed after dyeing the yarn or fabric to improve the look, performance, or feel of the finished textile or clothing.
  7. 7. Characteristics of textile effluens contd. Inorganic Substances • Oxidising and Reducing agents. • Salts • Acids • Alkalis
  8. 8. Organic Substances • Dyes • Organic acids • Thickeners • Finishing agents • Detergents • Textile auxiliaries Characteristics of textile effluents contd.
  9. 9. Dye materials used in various textile industries Various dye material are being used in textile industry depending on the variety of fiber. • Cellulose fiber : Direct dyes, Reactive dyes, Vat dyes, Azo dyes, Sulfide dyes. • Wool : Acid dyes • Silk : Direct dyes, Acid dyes.
  10. 10. Dye material uses in various textile industries contd. • Polyester : Azo dyes, Disperse dyes • Polyester-cotton : Disperse/Vat dyes, Disperse/Insoluble dyes • polyacrylonitrile fiber : Cationic dyes , Disperse dyes • polyacrylonitrile fiber -wool : Cationic dyes, Acid dyes
  11. 11. Dye material uses in various textile industries contd. • Vinylon : Direct dyes, Vat dyes, Sulfur dyes, Acid dyes
  12. 12. Properties of dyes Direct dyes • Substantive dye is a dye used in a process in which dye molecules are attracted by physical forces at the molecular level to the textile. • Water soluble dyes. • It is anionic in nature. • Needs electrolyte for exhaustion.
  13. 13. Properties of dyes contd. Reactive dye • In a reactive dye a chromophore contains a substituent that is activated and allowed to directly react to the surface of the substrate. • Reactive dyes have good fastness properties owing to the bonding that occurs during dyeing.
  14. 14. Properties of dyes contd. Vat dyes • Vat dyes are an ancient class of dyes, based on the natural dye, indigo, which is now produced synthetically. • Insoluble in water. • Have high color fastness. • Poor rubbing fastness, can be mitigated with special treatments to the fabric.
  15. 15. Properties of dyes contd. Azo dyes • The dyes containing insoluble azo group (‐N=N‐) are known as azoic dyes. • They have fair to good fastness properties, but not so good as the carbonyl and phthalocyanine classes. • Cost-effective. • Gives bright high intensity colours.
  16. 16. Properties of dyes contd. Sulfide dyes • A dye containing sulfur and soluble in a 0.25-0.50% sodium sulfide solution, and used to dye cotton. • Are water insoluble. • These dyes have good all round fastness except to chlorine. • They are cheap, have good wash-fastness.
  17. 17. Properties of dyes contd. Acid dyes • An acid dye is a dye, chemically a sodium (less often– ammonium) salt of a sulfuric, carboxylic or phenol organic acid. • Soluble in water. • Ionic bonding with fiber cationic sites.
  18. 18. Properties of dyes contd. Disperse dyes • Disperse dyes are the only water insoluble dyes that dye polyester and acetate fibers. • Disperse dye molecules are the smallest dye molecules among all dyes.
  19. 19. Properties of dyes contd. Cationic dyes • Cationic dyestuff is a group of water soluble dyes with bright colours. • They ionize into cationic ions in water. • Forms ionic linkage with acid groups on fibers. • Water soluble dyes.