Environmental friendly processing of textile fibres
Naturally Coloured Cotton
Ph.D. Research Scholar
Deptt. of Textile and Apparel
India is the world’s third largest producer of cotton
textile—after China and USA—and the second largest
cotton consumer after China.
Cotton accounts for 40% of the total global fibre
production and is the most important fibre in the
world. Cotton as a crop as well as a commodity plays
an important role in the agrarian and industrial
activities of the nation and has a unique place in the
economy of our country.
Cotton popularly known as “White Gold” is grown
mainly for fibre. India has been a traditional home of
cotton and cotton textiles. It provides livelihood to 60
million people who depend on cotton cultivation,
processing, trade and textiles (Singh, 2010) .
Cotton is produced in three zones in India, the Northern zone
comprising the states of : Punjab, Haryana and Rajasthan.
The Central zone comprising the states of : Maharashtra, Madhya
Pradesh and Gujarat
The Southern zone comprising the states of : Andhra Pradesh,
Karnataka and Tamil Nadu.
In Haryana the cotton area includes five major districts in this belt
namely: Sirsa, Fatehabad, Hisar, Jind and Bhiwani and constitutes
more than 90% area of crop in the state.
Advantages of Cotton
• Absorbs up to 27 times its
own weight in water
• Has a comfortable, soft
• Is easy to launder
•Takes dye easily, good
• Is durable and strong
• Conducts heat well
• Resists abrasion
• Resists pilling and moths
• Is easy to handle and sew
Shrinks and wrinkles
Colour loss by
bleeding and sunlight
Damaged by mildew
What is Eco-Friendly?
Eco-friendly fabrics are made from fibres that do not require
the use of any pesticides or chemicals to grow.
They are naturally resistant to mould and mildew and are
disease free. Hemp, linen, bamboo and ramie are eco-friendly
Organic cotton is cotton that has been grown on earth that has been
without the use of chemical pesticides and defoliants for at least three
Fertilizers that are used include compost, manure, naturally derived
mineral and plant fertilizers and crop rotation. Insect controls
involve the use of beneficial insects and natural pesticides certified
for organic crops.
Organic cotton feels softer, smells cleaner, and is less likely to trigger
allergies. The sustainable farming practices used to grow organic
cotton do not pollute groundwater, surface water, soil, or air. In fact,
soil quality is actually improved by the production of organic cotton.
Why Go Organic or Eco-Friendly?
Chemicals and pesticides invade drinking water and groundwater,
polluting its fish and even reaching human consumption. Organic and
eco fibres grow without any pesticides or chemical fertilizers.
Eco and organic fabric biodegrade naturally over time. Synthetic fibres
eventually become waste and let off harmful toxins when they degrade.
Many people are allergic or dislike wearing synthetic textiles. Eco
fabrics have all the properties of the new synthetic breathable fibres
with added softness and drape. They feel better against the skin.
Not only do its chemicals reach into our groundwater, conventional
clothing is worn next to our most porous organ- our skin.
Organic and eco-fibers are natural and do not contain irritating
chemicals. Many of them are also considered hypoallergenic and
Organic foods have been around for awhile and it is a natural
evolution that organic and eco friendly fabrics will also gain
Eco and Organic fabrics once considered an alternative are now
entering into the mainstream.
OCIA Regulations (for cotton)
OCIA International (Organic Crop Improvement Association) is a non profit,
member owned organization which always provides its members with the
highest quality of certification as well as providing access to global organic
There are different regulations depending on where the fabric is being
produced and where it is being sold and OCIA takes each different area and
it’s regulations into account before certifying.
All of our organic cotton is produced in China and India, and to sell in
Canada there are no regulations or further certifications that a product has to
To sell an “organic” product in the United States, the product must be
certified under the NOP (National Organic Program). This is covered under
the OCIA certification therefore we are certified under this program as well.
EKO Quality Symbol
The square EKO quality symbol is an international quality symbol for
Control Union Certifications sustainable textile products.
It is used when raw materials originate from organic cultivation and are
processed using the sustainable textile production methods.
When the EKO quality symbol is attached to our fabric, it means:
1. The fabric's fibres come from inspected, organic farming, from organic
production methods or from NOP certified cotton.
2. The fabric complies with the Control Union Certifications Standards.
Organic and ecological textiles:
The organic & ecological textiles is continuing to grow, led by
the increasing awareness of the consumers who are now informed of the
risks conventional textiles pose to health and the environment.
For ensure the customer in your responsible project, it is important to ask
for a control of your goods or activities in order to guarantee the organic
or ecological propriety. For that, Ecocert offers you to certify according
•GOTS (Global Organic Textile Standard) for a social and environmental
•OCS (Organic Content Standard) to guarantee the traceability of
organic textiles .
•Ecological & Recycled Textiles (Ecocert Standard) to claim the
GOTS – GLOBAL ORGANIC TEXTILE STANDARD
GOTS is a standard for organic textiles and it is formulated by four
organic bodies OTA (Organic Trade Association) USA, SA (Soil
Association) UK, JOCA (Japan Organic Cotton Association) and IVN
The standard gives clear restrictions and requirements for –
Organic Fibre Production
Textile Auxiliaries, dyestuff and pigments
All stages of production eg. Spinning, weaving, knitting, pre-treatment,
dyeing, printing, finishing.
Waste water treatment
Storage, packaging and transport
Quality assurance system
End product criteria
Residue in accessories
The GOTS certification is issued by certification bodies such as
Control union, IMO, ecocert etc.
Texanlab is able to test products as per GOTS requirement and
certification can be done only by certification bodies.
Control Union Certifications Standards:
The natural fibres have to be organic. The standards reject any textiles
which contain heavy metals, which are toxic or non-degradable.
The input of additives, which harm the environment, is prohibited during
the total production process, and the finished products may not contain
residues or harmful means.
CU Certifications encompass all stages of textiles production which
include raw materials origin, pre-treatment (washing, bleaching, etc.),
dyeing and printing, after treatment, storage, labelling of the final product
Textile processing is a growing industry that traditionally has used
a lot of water, energy and harsh chemicals.
Due to the ever-growing costs for water and energy worldwide
investigations are carried out to substitute conventional chemical
textile processes by environment-friendly and economically attractive
bioprocesses using enzymes.
Enzymes are used in a broad range of processes in the textile
Enzymes are specific and fast in action and small amounts of
enzyme often save large amounts of raw materials, chemicals, energy
Cotton Textile Processing
Properties of Enzymes
Used in Textiles
2. Enzyme accelerates
An enzyme accelerates the
rate of particular reaction
by lowering the activation
energy of reaction. The
enzyme remains intact at
the end of reaction by acting
1. Enzymes operate
Each enzyme have optimum
temperature and optimum pH
i.e. activity of enzyme at that
pH and temperature is on the
For most of the enzyme
activity degrades on the both
sides of optimum condition
3. Alternative for
Enzymes can be used as best
alternative to toxic, hazardous,
pollution making chemicals .
Also some pollutant chemicals are
When we use enzymes there is no
4. Enzyme acts only on
Most enzymes have high degree of
specificity and will catalyse the
reaction with one or few substrates
One particular enzyme will only
catalyse a specific type of reaction.
Enzymes used in de-sizing do not
affect cellulose hence there is no
loss of strength of cotton
5.Enzyme are easy to control
Enzymes are easy to control because
their activity depends upon
6.Enzymes are biodegradable
At the end of reaction in which
enzymes used we can simply drain
the remaining solution because
enzymes are biodegradable and do
not produce toxic waste on
degradation hence there is no
The mechanism of working of enzymes
a) Substrate fits exactly into active site
b) Enzymes join with substrate for short while.
c) Enzymes alter substrate into products and products are released .
d) Enzymes are not used in the process and continue action if more
substrate is provided.
E + S ES (Enzyme substrate products)
ES E + Different products.
After weaving, the sizing agent and natural non-cellulosic materials
present in the cotton must be removed in order to prepare the fabric
for dyeing and finishing.
Before the discovery of amylases, de-sizing used to be carried out by
treating the fabric with acid, alkali or oxidizing agents at high
(Etters & Annis 1998; Cegarra 1996)
A) Acid desizing, B) Oxidative desizing
Disadvantages of acid desizing: May degrade cotton.
Disadvantages of oxidative desizing: Residual peroxide, High pH due
to caustic, and high TDS.
Steps Involved in Cotton Textile Processing
Nowadays amylases are commercialized and
preferred for de-sizing due to their high
efficiency and specificity, completely removing
the size without any harmful effects on the
The starch is randomly cleaved into water
soluble dextrins that can be then removed by
washing. This also reduced the discharge of
waste chemicals to the environment and
improved working conditions.
The chemical treatment was not totally effective
in removing the starch, leading to imperfections in
dyeing, and also resulted in a degradation of the
cotton fibre destroying the natural, soft feel of the
Scouring is removal of non-cellulosic material present on the surface of
Raw cotton contains about 90 % of cellulose and various non-cellulosic
such as waxes, pectins, proteins, fats, lignin-containing impurities and
The goal of the cotton preparatory process is the remove the
hydrophobic and non-cellulosic components and produce highly
absorbent fibres that can be dyed and finished uniformly.
Traditional scouring Enzymatic scouring
Scouring, improves the wet ability of the
fabric and normally uses alkalis, such as
However, these chemicals also attack the
cellulose, leading to reduction in strength
and loss of fabric weight.
Furthermore, the resulting wastewater
high COD (Chemical Oxygen
high BOD (Biological Oxygen
high salt content
[Buschle-Diller et al. 1998].
Enzymatic, leaves the cellulose structure
almost intact, preventing cellulose weight
and strength loss.
It has a number of potential advantages
over traditional scouring.
It is lower BOD, COD, TDS (Total
Performed at neutral pH, which reduces
total water consumption .
The treated yarn/fabrics retain their
The weight loss is reduced or limited
compared with processing in traditional
and it increases cotton fibre softness.
The purpose of cotton bleaching is to decolourise natural pigments and to
confer a pure white appearance to the fibres.
(Hedin et al., 1992; Ardon et al., 1996)
Step- 4 Bleaching
Mainly flavonoids are responsible for the colour of cotton. The most
common industrial bleaching agent is hydrogen peroxide.
Conventional preparation of cotton requires high amounts of alkaline
chemicals and consequently, huge quantities of rinse water are generated.
However, radical reactions of bleaching agents with the fibre can lead to a
decrease in the degree of polymerisation and, thus, to severe damage.
Therefore, replacement of hydrogen peroxide by an enzymatic
bleaching system would not only lead to better product quality due
to less fibre damage but also to substantial savings on washing water
needed for the removal of hydrogen peroxide.
An alternative to this process is to use a combination of suitable
Amyloglucosidases, pectinases, and glucose oxidases are selected that
are compatible concerning their active pH and temperature range.
Bio-polishing is a finishing process that improves fabric quality by mainly
reducing fuzziness and pilling property of cellulosic fibre.
The objective of the process is elimination of micro fibrils of cotton
through the action of cellulase enzyme .
The main characteristics imparted to the fabric during bio-polishing
treatment are as follow:
Cleaner surface is obtained conferring a cooler feel.
Lustre is obtained as a side effect
Fabric obtains softer feel.
Tendency of the fabric to pill ends.
(Stewart, 2005; Cavaco-Paulo, 1998; Cavaco-Paulo et al., 1996; Lenting and
Stone washing of denim by using traditional method
Denim is heavy grade cotton. In this dye is mainly adsorbed on the
surface of the fibre.
That is why fading can be achieved without considerable loss of
strength. In traditional process sodium hypochlorite or potassium
permanganate was used called as pumice stones.
Disadvantage of these method are as follows:
Pumice stones cause large amount of back-staining.
Pumice stones are required in very large amount.
They cause considerable wear and tear of machine.
(Pedersen and Schneider, 1998)
These disadvantages lead to give rise the process of use of enzymes.
Cellulase enzyme is used in denim washing.
Cellulase works by loosening the indigo dye on the denim in a
process known as “Bio-Stonewashing”.
A small dose of enzyme can replace several kilograms of pumice
The use of less pumice stones results in less damage to garment,
machine and less pumice dust in the laundry environment.
More recently, some authors showed that laccase was an effective
agent for stone-washing effects of denim fabric with and without
using a mediator.
(Campos et al., 2001; Pazarloglu et al., 2005).
Enzymatic treatment to denim
Use minimum to start so that less is wasted and therefore, will cause
least discharge to the environment.
Reuse and recycle the products wherever possible so that their useful
life is enhanced and the period to discard them to environment is
Change ,replace or design the processes in order to be more
environmental friendly by use of eco-friendly chemicals ,energy
Points to be remember while starting processing of
Processing Of Silk
type reactive dyeing
Ahmed et al. carried out the dyeing of the natural dyes kamala
,indigo, turmeric and heena on mulberry silk . It was found that the
general appearance luster and texture of kamla dyed silk fabric was
better than that of the other dyed samples.
Eco-friendly dyeing of silk fabric
Processing Of Wool
Carbonizing Triwool solvent
Low pressure and low
Schumacher et al. shown that protease treatment improves the whiteness as
well a s dyeability with lanasol reactive dye.
Bleaching of wool :
3 stabilizer with H2O2
Sodium di-ethylene triaminopentamethyl phosphate
Sodium pyrophosphate+ ammonium oxalate
Sokolowaska et al. synthesized 1:2 iron complexed azo dyes and
compared their properties with 1:2 chromium and 1:2 cobalt commercial
They found that the new black dyes are very good for wool and nylon
from the light and rubbing fastness point of view, at the same time they
Alternative solution for non eco-friendly chemicals to reduce
pollution load on environment
Processing Of Polyester
Disperse dyes were initially was developed for acetate fibre. However,
with the introduction of polyester and other hydrophobic fibres, disperse
dyes became a large and pre eminent group of dyes.
To produce acceptable dyeing results, three innovative methods for
application of these dyes on polyester and acetate fibres were developed.
The three methods are: carrier dyeing, high temperature dyeing, thermosol
Modification in dyeing processes resulted in reduced cycle time and less
water, chemicals and energy consumption. This reduced the pollution load
in the effluent.
During polyester dyeing, chlorinated carriers should be avoided and high
BOD/COD acetic acid should be replaced by alternative products like
Duracid. Safe disperse dyes with ecofriendly dispersing agents should be
Ecofriendly dyeing of polyester
Because of low hydrophilicity , the surface of PET fabrics can not wet easily
this causes some difficulties in finishing, washing and dyeing.
In addition ,due to the buildup of electrostatic charge and pilling on the
surface of PET fabrics, the wearing comfort of the clothing is diminished.
In order to solve these problems , many attempts have been made to modify
the low hydropilicity of the surface of PET fabrics.
Enzymatic hydrolysis is more advantageous than conventional hydrolysis by
alkali treatment as it consumes less amounts of energy further no harsh
chemicals are required.
Lipase ,cutinase and esterase enzymes are used for enzymatic hydrolysis.
Thus enzyme hydrolysis on ester linkages cause producing hydroxyl and
carboxyl groups on the surface of the fabric , so surface hydrophilicity of
PET fabrics could be increased.
PET plastics are also known as Polyethylene terephthalate (PETE). PET's
recycling code within the three chasing arrows, is a number one. These
plastics are usually beverage bottles (i.e. water, soda, and fruit juice
According to the EPA, plastic accounts for 12% of the total amount of
waste we produce. Recycling plastic reduces air, water, and ground
pollution. Recycling is only the first step; investing and purchasing products
manufactured from recycled materials is the next of many steps to living
Clothing can be made from plastics. Seventy percent of plastic-derived
fabrics come from polyester, and the type of polyester most used in fabrics
is polyethylene terephthalate (PET).
PET plastic clothing come from reused plastics, often recycled plastic
bottles. The Coca Cola Company, for example, created a "Drink2Wear" line
of T-shirts made from recycled bottles.
Disperse Dye Chemical Class Of Dye Status Of Dye
Yellow56 Reddish yellow Banned
Processing Of Acrylic
The selection of proper dyes and
chemicals are of great importance for
eco-friendly acrylic dyeing.
One positive aspect of acrylic dyeing
from ecological point of view is 90-
97% exhaustion of cationic dyes on
The following dyes are available in
India are safe for acrylic dyeing:
Basic orange: 22
Basic brown: 1
Basic black: 36
Processing Of Nylon
The main pollutant present in the nylon exhaust dye liquor are exhausted dye
acetic acid, dye fixing agents and heavy metallic compounds.
In place of acetic acid which is used for maintain the ph in nylon dyeing
,suitable substitute should be used . the use of formic acid in place of acetic acid
can reduce bod in effluent.
levelling agents which contain chlorinated hydrocarbon or bleaching with
active chlorine must be avoided to eliminate significant amount of AOX(
activated carbon absorbable organo halogens) in the effluent.
The following safe dyes are available in India for dyeing nylon.
Acid orange: 7,10A,74,80,82,86
Acid blue: 25,89,113,120
Acid green: 1,9,10
Dyeing Of Nylon
Bamboo textiles have many fantastic properties that combined
make this a truly amazing fabric :
breathable and cool, has a
nice lustre wonderful silky softness.
quickly absorb and evaporate human sweat.
avoids pilling and shrinkage problems.
Bamboo fibers are quickly emerging now in the fashion world.
The fabric woven with bamboo yarn is light, almost
Bamboo -Thick Pulp - Fine Pulp - Bamboo Fibre - BambooYarn - Fabric.
Polylactic Acid Fibres
Cargill Dow polymers which was started in 1997, is the leader in the
technology of polylactic acid (PLA).
A new synthetic biodegradable polymer is obtained from the
renewable source such as corn. It is also possible to use other plant
materials such as rice, wheat, sugar beets and even agricultural waste.
A renewable resource such as corn is milled, separating starch
from the raw material. Unrefined dextrose/sugar, in turn, is processed
The dextrose/sugar is turned into lactic acid using a fermentation
process similar to that used by beer and wine producers.
Through a special condensation process, a cyclic intermediate
dimer, referred to as lactide, is formed.
This monomer lactide is purified through vacuum distillation.
Ring opening polymerization of the lactide is accomplished with a
solvent free melt process.
Soy fabrics are derived from the hulls of soybean-a manufacturing by
product. Soy fabrics can be blended (i.e. 30%) or made entirely out of soy
Soy clothing is largely biodegradable, so it has a minimal impact on
environment and landfills.
Although not as durable as cotton or hemp fabrics, soy clothing has a soft,
Soy clothing is known as the vegetable cashmere for its light and silky
sensation. Soy fabrics are moisture absorbent, anti-bacterial, and UV
Lyocell is a regenerated cellulose fiber made from dissolving
pulp (bleached wood pulp). It was developed and first manufactured for
market development as Tencel.
Lyocell first went on public sale as a type of rayon in 1991. It shares many
properties with other cellulosic fibers such as cotton, linen, ramie and
Some main characteristics of lyocell fibers are that they are soft, absorbent,
very strong when wet or dry, and resistant to wrinkles; lyocell fabric can be
machine- or hand-washed or drycleaned, it drapes well, and it can be dyed
many colors, and can simulate a variety of textures such as leather, and silk.
PLASMA TECHNOLOGY IN TEXTILE
What is Plasma?
Highly reactive material used to modify the surface of the
substrate. i.e. Plasma activation or modification.
It is a substance, usually a gas whose atoms have one or more
electrons detached and hence ionized.
Overall neutral as it consists of equal no of –ve & +ve ions called
· High density plasma not suitable for textile applications.
· Plasma density depends on temperature and magnetic field applied.
How plasma is produced?
1) By providing heat to gas (high temperature) or when
kinetic energy of gas particles rises equal to ionization
energy of gas.
E.g. Atmosphere of most stars, gases on the upper atmosphere
of earth (about 400km) gas within the glass tubing of Neon
2) To pass high energy electrons to low pressure gas. The
individually charged plasma particles can be controlled by
electric or magnetic field.
3) By applying electric field to low pressure gas.
How Plasma Works On Textiles?
· It is only a surface reaction.
· Modifies the surface in nm range (100nm)
Coat the fibre with nm thin film depending on gas used.
This technique can be used to make fibre. Hydrophilic properties can be
imparted by oxygen plasma.
· Hydrophobic properties can be imparted by Hexafloroethane plasma.
· Improve colour fastness.
· Improve dyeing rates.
· Improve shrinkage resistance.
· Reduce inflammability.
· Improved pigment fixation.
· Flouring plasma for medical textiles.
· Anti felting on wool.
· To facilitate the removal of size & contaminants
General Application of Sol-Gel for Textile Use
Recently, investigations have been conducted to improve properties of
textile fabrics by embedding various finishes in sol-gel coating to
enhance fabric performance.
The following section will focus on different sol-gel applications that
create new functional properties in textile fabrics. Textiles coated with
sol-gel are reported to impart many important properties
What is Microencapsulation???
Technique to prepare microcapsules, small
particles that contain a core- material
surrounded by coating or shell of limited
permeability (Benita, 1996).
The core content may be released by friction, pressure, change of
temperature, diffusion through the polymer wall, dissolution of
the polymer wall coating, biodegradation etc.
Reasons for using
Process Chemicals used Health hazards
Singeing Small amounts of exhaust
gases, negligable impact
Desizing - Enzymes or H2SO4 for
starch, detergents and alkali
for PVA and CMC
Bloating and Diarrhoea.
Irritant to eyes and skin
Scouring NaOH,Na2CO3, surfactants,
Non-ionic detergents may cause
bloating and Diarrhoea, Irritant
to eyes and skin.
Bleaching -Hypochlorite -
Chlorine gas released, causing
severe irritation of respiratory
tract and eyes tract and eyes
Mercerization NaOH, surfactants, acid,
Health Hazards Associated With Chemicals Used In Textile
Processing textile Industries
Process Chemicals used Health hazards
- Fluorinated chemicals
Intense irritation of eyes and nose
Causing vomiting, and coughing.
High concentration can cause
- Aluminum salts
- Zircon salts
- fluorocarbon resins
- Toluene may be used in solvent
coating operations can cause,
headaches, confusion weakness, and
memory loss, and affects function
of kidney and liver , formation of
ozone which causes asthma
Organic farming contributes to the different
Protecting surface and groundwater quality (eliminating
contaminants in surface runoff)
Reduced risk in insect and disease control by replacing insecticide
with the manipulation of ecosystems
Long-term prevention of pests through beneficial habitat planting.
Conservation of biodiversity
Eliminate the use of toxic chemicals used in cotton.
Organically grown crops also yield soils with higher organic matter
content, thicker topsoil depth, higher polysaccharide content, and
lower modulus of rupture; therefore reducing considerably soil
According to R.B. CHAVAN the dye consumption pattern indicates that
in the next five years, the sulphur, direct ,vat and indigdyes will remain
constant , azoic will continue to decline and reactive dye will show
The lack may be due to the following factors:
High price and limited supply incase of vat dyes
Environmental problems associated with vat, sulphur and azoics.
Technological obsolescence in case of direct dyes.
Most of the reactive dye manufacturers are concentrating on addressing
the following environmental problems associated the reactive dyes:
Colour in effluent
Minimization of chemical usage
These problems associated with the reactive dyes can be minimized by
using bi-functional reactive dyes.
ICI has developed the procion supra range with two monochlorotriazine
groups per molecule.this approach led to better dye utilization and resulted
in less hydolyzed dye and less effluent.
In 1980 sumitomo launched the first range of the hetero bifunctional dyes
which carry two different reactive groups.
Advantages of bi functional reactive dyes:
high dye affinity and high dye fixation
Stable dye fibre bond
Less dye to be removed from fabric after dyeing
Rinsing step is much faster
Less water is needed for wash off
Less dye effluent
Approach to minimize the salt load:
Dyeing at low liquor ratio
Using reactive dye which gives high exhaustion and fixation at low
Disadvantages of High salt containing dyes
Rivers and lakes get polluted with effluent containing high salt
Fresh water organism can have toxic effect
In the regions where scarce fresg water resources . Such water has to
be used for irrigation
If the salt content is too high , the soils become overloaded with salt ,
making the land infertile and Ultimately useless
Higher fixation rate of Cibacron LS reactive dye
Alternative reducing systems solution for dyeing
cotton with vat dye
Vat dyes are used by using sodium hydro sulphite as reducing agent and
sodium hydroxide as an alkali.
A few by products are formed are sulphur compound like Na2S and
NaHS etc., which pollute air through the formation of H2S.
At the same time ,the salts of sulphur in the form of sulphates and
sulphites contaminate sewage and lower its ph and show corrosive action
on concrete pipes.
Other problems associated with the use of Na2S2O4 are its cost and
low storage stability.
Researchers have developed alternate reducing system s which are
eco-friendly in nature.
Such few systems include electrochemical reduction , use of organic
reducing agents like hydroxy acetone, iron pentacarbonyl compounds
and iron complexes.
This reducing system is bio compatible and gives 20 % higher indigo
uptake along with less consumption of assisting chemicals.
Alternative reducing systems solution for dyeing cotton
with vat dye
Sodium sulphide is commonly used for the reduction in the application
of sulphur dyes on cotton .
Residual sodium sulphide acts as contaminant in the effluent. Sodium
sulphide causes no marked odour nuisance above ph 9 but in acetic ph,
gaseous H2S is liberated ,which gives fowl smell of rotton eggs and is
toxic when inhaled.
Its odour threshold value is 10 ppm.
Century mill at mumbai also established , on commercial scale , that
sodium sulphide can be totally replaced with glucose obtained from
hydrolysis of starch .
Other sugars and related substances like hydroxy acetone have been
examined in laboratory , but none of them were found to offer any
advantage over glucose.
The chitosan has many excellent properties, such as broad spectrum
anti-biotics, non –toxic, bio-compatibility, bio-degradation, etc. It is
used as anti bacterial and crosslinking with fabric .
As a green finishing agent the chitosan can meet the request of
Meanwhile, the chitosan has some merits such as absorbency, air
permeability, microbial degradation, bio activity, sequestering activity,
enzyme fixation etc.
Its sources is rich, it is suitable for producing the antibacterial fabric
with its non –toxic and non-pollution
Crease resistant and anti bacterial finish by using
Mona verma , 2013
A range of textile products based on synthetic antimicrobial agents such
as triclosan, metal and their salts, organometallics, phenols and
quaternary ammonium compounds have been developed and few of them
Although the synthetic antimicrobial agents are very effective a range of
microbes and give a durable effect on textiles, they are cause of concern
due to the associated side effects, action on non-target microorganism
and water pollution.
Joshi et al. (2009)