Impact of dyes on Environment and Way to reduce.

Impact of Dyes on Environment and Way to reduce.

Introduction:

Today’s consumers demand that manufactured goods must not only meet quality and safety requirements, but also be sourced and manufactured using sustainable practices that do not adversely impact the environment, community, society or economy. Textile dyes are the most responsible elements for environmental hazardous in the textile industry. In this article I will discuss problem caused by textile dyes in the environment and way to reduce.

The colour of textiles always fascinates mankind, and a long range of textile colors are available to people. This step of textile processing is very crucial with respect to environmental concerns, as a large amount of unadsorbed dyes is discarded into water bodies. The expansion of the use of synthetic dyes overburdened the pressure on environment and consequently increased pollution.

The textile wet processing industry has a major impact not only on the nation’s economy but also on the economic and environmental quality of life in many communities. Textile processing specially dyeing process generates various types of waste streams, including water-based effluent as well as air emissions, solid wastes and hazardous wastes. Besides, dyes contain heavy metals and hazardous pollutants. During the manufacture of some dyes, mercury or other metals are used as catalysts and may be present as a by-product. Many anthraquinone dyes are derived by sulphonation in the presence of mercury catalysts. Some dyes include metals as an integral part of the dye molecule as the metallic content is essential to the performance of a dye as a textile colorant.

Fig: Problem of dyes on the environment.

In earlier days, the dyestuff selection, application and use were not given a major consideration with respect to their environmental impact. Now, dye manufacturers are now very conscious about the environmental impact of dyestuffs along with the requirements of better economy of the manufacturing process, and the high tinctorial value and higher wet fastness of dyed textiles. Some dye manufacturers make use of mercury-free manufacturing practices.

Problem of Dyes on Environment:

The textile dyes, along with a large number of industrial pollutants, are highly toxic and potentially carcinogenic, so that they are related to environmental degradation and various diseases in animals and humans. The dyeing process, whether it is by natural dyes or synthetic dyes, has an impact on the environment to some extent as a result of spilling out of nondegradable dye compounds or hazardous metal ions used as mordants to fix dye molecules on textile surfaces. Dyes cause a lot of problems in the environment. The problem which are caused in environment by dyes are given below:

👉Depending on exposure time and dye concentration, dyes can have acute and/or chronic effects on exposed organisms.

👉The presence of very small quantities of dyes in water (less then 1 ppm) is highly visible due to their brilliance.

👉The greatest environmental concern with dyes is their absorption and reflection of sunlight entering the water. Light absorption diminishes photosynthetic activity of algae and seriously influence on the food chain.

👉Dyes can remain in the environment for an extended period of time, because of high thermal and photo stability. For instance, the half-life of hydrolysed Reactive Blue 19 is about 46 years at pH 7 and 25°C.

👉Many dyes and their breakdown products are carcinogenic, mutagenicand/or toxic to life. Dyes are mostly introduced into the environment through industrial effluents.

There is ample evidenc of their harmful effects. Triple primary cancers involving kidney, urinary bladder and liver of dye workers have been reported. Most of the dyes, used in the textile industry are known only by their trade name, while their chemical nature and biological hazards are not known. The systematic backtracking of the flows of wastewater from textile-finishing companies led to the identification of textile dyes as a cause of strongly mutagenic effects. The textile dyes used in the textile-finishing companies in the European Union were examined for mutagenicity. According to the obtained results the dyes that proved to be mutagenic have been replaced with less harmful substances.

The degradation product of dyes could be carcinogenic. The formation of Decoloration of Textile Wastewaters 177 carcinogenic aromatic amine o-tolidine from the dye Direct Blue 14 by skin bacteria has been established.

👉Textile dyes can cause allergies such as contact dermatitis and respiratory diseases, allergic reaction in eyes, skin irritation, and irritation to mucous membrane and the upper respiratory tract. Reactive dyes form covalent bonds with cellulose, woollen and PA fibers. It is assumed that in the same way reactive dyes can bond with –NH2 and –SH group of proteins in living organisms. A lot of investigations of respiratory diseases in workers dealing with reactive dyes have been made. Certain reactive dyes have caused respiratory sensitisation of workers occupationally exposed to them.

Public perception of water quality is greatly influenced by the color. So, the removal of color from wastewater is often more important than the removal of the soluble colorless organic substances. Removal of the dyes from the textile wastewater is often very costly, but a stringent environmental legislation has stimulated the textile sector in developing wastewater treatment plants.

Ways to Reduce Environmental Pollution by Dyes:-

The dyeing process as a whole creates several problem of dyes on environment, which are possible to reduce by knowing their sources and taking appropriate measures. These sources and the measures adoptable may be categorized as follows:

1)Textile raw fibers may be contaminated with polluting chemicals.

2) Dyes contain pollutants and hazardous materials.

3) Auxiliary chemicals used during dyeing may have their own impact.

4) Dyeing operations are water-intensive leading to large volumes of effluent.

5) As far as possible recycling, reuse of the dyestuffs and chemicals should be practised.

6) Implement overall best management practices.

Conclusion:

Methods used for dyeing textiles are quite important to decide the extent of polluting the environment. Microwave and sonicator dyeing and the application of compounds with pad-dry cure method are considered as effective dyeing processes that lead to high adsorption of dyes and to ultimately protecting the environment. The use of ecofriendly or natural compounds such as chitosan and biomordants to enhance the substantivity of dyes towards textiles in place of toxic metals may be a great step towards a safe environment and eco-friendly dyeing. The use of ecofriendly chemicals, dyes, and suitable techniques for maximum output without simultaneous generation of waste would be important aspects to establish a safe relationship between the textile industry and the environment today and in the future.

Ref:-https://textilelearner.net