1. Characteristics of industrial textile
effluents and different type of dye
materials used in textile industry
Mithun Chouhan|10CH10026
Department of Chemical Engineering

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. • 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. • -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. • 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. 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. Characteristics of textile effluens
contd.
Inorganic Substances
• Oxidising and Reducing agents.
• Salts
• Acids
• Alkalis

8. Organic Substances
• Dyes
• Organic acids
• Thickeners
• Finishing agents
• Detergents
• Textile auxiliaries
Characteristics of textile effluents
contd.

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. 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. Dye material uses in various textile
industries contd.
• Vinylon : Direct dyes, Vat dyes,
Sulfur dyes, Acid dyes

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. 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. 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. 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. 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. 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. 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. 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.