382
(a) Substantive dyes: These types of dyes are chemically fixed to the fiber and
do not require any chemicals are known as substantive dyes.
(b) Adjective dyes: These types of natural dyes need mordant for making dyes
colorfast are referred to as adjective dyes.
(2) Synthetic dyes: Synthetic dyes are mainly obtained from organic and inorganic
compounds. These dyes are very popular as they are very cheap and easy to use
including wide range of colors (Raval et al. 2017).
Generally, synthetic dyes are categorized into three groups, (1) anionic (acid,
reactive, and direct dyes), (2) cationic (basic dyes), and (3) non-ionic (disperse
dyes). Table 15.1 represents the classification of dyes based on their different
applications.
15.2.3 Toxicity Effect of Dyes to the Environment
and Human Health
Large-scale industrial application of synthetic dyestuffs causes intractable troubles
in the environment. Due to the high intensity of colors in water, dyes are highly visible to human eye even in a very small concentration that is highly unacceptable on
aesthetic grounds (Gupta and Suhas 2009). Apart from the aesthetic issues, the
absorption of sunlight by the dyestuffs in the water can have serious environmental
concern (Rai et al. 2005). The dyes are very toxic and carcinogenic because of the
presence of aromatics, metals, and they block the light penetration and affect the
biological metabolism process by upsetting the photosynthetic activity in aquatic
life. In various types of microbiological and fish species, dyes are very toxic/teratogenic and mutagenic (Gong et al. 2005; Gupta and Suhas 2009). Additionally, it is
also responsible for severe damages to human health including dysfunction of the
liver, kidney, brain, and reproductive system. Reactive dyes are highly water- soluble
and chemically stabled colored effluent which is a critical issue for the environment.
Due to the presence of toxic amines in the water, azo dyes are extremely toxic.
Anthraquinone dye is very stable and takes very long time for degradation (Yagub
et al. 2014). Both the quantity and quality of effluent from various industries are a
matter of concern for the public and governments (Parsa and Negahdar 2012). Since
most of the dye compounds have been accounted as toxic, recalcitrant, carcinogenic, mutagenic, and chemically and photo-chemically stable, they are very threatening to human health as well as environment, and as the usage of synthetic dye is
increasing so, it becomes a great challenge in the area of research for industrial
effluent treatment (Sharma and Kaur 2018). Therefore, much more attention has
been paid on effective, economical, and feasible specific methods and technologies
M. Sardar et al.
(a) Substantive dyes: These types of dyes are chemically fixed to the fiber and
do not require any chemicals are known as substantive dyes.
(b) Adjective dyes: These types of natural dyes need mordant for making dyes
colorfast are referred to as adjective dyes.
(2) Synthetic dyes: Synthetic dyes are mainly obtained from organic and inorganic
compounds. These dyes are very popular as they are very cheap and easy to use
including wide range of colors (Raval et al. 2017).
Generally, synthetic dyes are categorized into three groups, (1) anionic (acid,
reactive, and direct dyes), (2) cationic (basic dyes), and (3) non-ionic (disperse
dyes). Table 15.1 represents the classification of dyes based on their different
applications.
15.2.3 Toxicity Effect of Dyes to the Environment
and Human Health
Large-scale industrial application of synthetic dyestuffs causes intractable troubles
in the environment. Due to the high intensity of colors in water, dyes are highly visible to human eye even in a very small concentration that is highly unacceptable on
aesthetic grounds (Gupta and Suhas 2009). Apart from the aesthetic issues, the
absorption of sunlight by the dyestuffs in the water can have serious environmental
concern (Rai et al. 2005). The dyes are very toxic and carcinogenic because of the
presence of aromatics, metals, and they block the light penetration and affect the
biological metabolism process by upsetting the photosynthetic activity in aquatic
life. In various types of microbiological and fish species, dyes are very toxic/teratogenic and mutagenic (Gong et al. 2005; Gupta and Suhas 2009). Additionally, it is
also responsible for severe damages to human health including dysfunction of the
liver, kidney, brain, and reproductive system. Reactive dyes are highly water- soluble
and chemically stabled colored effluent which is a critical issue for the environment.
Due to the presence of toxic amines in the water, azo dyes are extremely toxic.
Anthraquinone dye is very stable and takes very long time for degradation (Yagub
et al. 2014). Both the quantity and quality of effluent from various industries are a
matter of concern for the public and governments (Parsa and Negahdar 2012). Since
most of the dye compounds have been accounted as toxic, recalcitrant, carcinogenic, mutagenic, and chemically and photo-chemically stable, they are very threatening to human health as well as environment, and as the usage of synthetic dye is
increasing so, it becomes a great challenge in the area of research for industrial
effluent treatment (Sharma and Kaur 2018). Therefore, much more attention has
been paid on effective, economical, and feasible specific methods and technologies
M. Sardar et al.