408
solution was as bad as using synthetic dyes. This is because of the fact that a mordant is needed to ensure natural dyes bond to fabrics. A mordant is a type of bonding
agent that helps to bind natural dyes to the material. Mordants are much more dangerous and more toxic than synthetic dyes (Kant 2011). Today, synthetic dyes are
staple materials which are used for colorizing cosmetics, textiles, printing, and plastics (Abdi et al. 2017; Ahmad et al. 2015). This is when the dyes are naturally rebellious materials and they are not easily degradable. Synthetic dyes have complex
molecular structures owing to their auxochromes and chromophores (Chacko and
Subramaniam 2011; Pan et al. 2017). Today, synthetic dyes are available in many
different types. The synthetic dyes can be categorized based on their chemical structure as presented in Table 16.1.
Sometimes, dyes are classified by their application or even by their solubility, as
tabulated in Table 16.2. Mordant, reactive, acidic, basic, and direct dyes are watersoluble dyes, while disperse, azo, and sulfur are examples of insoluble dyes (Rauf
and Ashraf 2012). Among the various dyes, azo dyes have the highest production
rate (~ 70%) and are the most widely used dyes throughout the world (Cotillas
et al. 2018).
Another classification of dyes is presented in Table 16.3. Acidic dyes are commonly utilized for dyeing wool, silk, nylon, and modified acrylic. These dyes are
also consumed in paper, cosmetics, inkjet printing, food, and leather industries.
Xanthan, azine, triphenylmethane, anthraquinone, nitro, nitroso, and azo are the
main classes of acidic dyes (Salleh et al. 2011). Acid red 57, acid blue 2, orange (I,
II), and methyl orange are conventional acid dyes. Basic dyes are utilized in dyeing
modified nylons, modified polyesters, and polyacrylonitrile as well as in pharmaceutical and paper industries. These are water-soluble cationic dyes and also consumed for wool, silk, and tannin mordant cotton (Salleh et al. 2011; Bouatay et al.
2016). Thiazine, cyanine, acridine, hemicyanine, oxazine, diazahemicyanine, malachite green, basic red 46, basic red 9, basic yellow 28, methylene blue, crystal violet, and basic brown are the main classes of basic dyes. Disperse dyes are utilized on
nylon, cellulose acetate, cellulose fiber, and acrylic fibers. These are water-insoluble
and nonionic dyes. The major classes are nitro, benzodifuranone, azo, anthraquinone, and styryl groups. Disperse blue, disperse yellow, disperse red, and disperse
orange are some usual examples (Forgacs et al. 2004).
Direct dyes are commonly utilized in dyeing cotton, leather, rayon, and paper
industries. If the dyeing process takes place in aqueous electrolytic solutions, direct
dyes have affinity to cellulose fiber. Stilbenes, oxazine, and polyazo compounds are
the major classes of direct dyes. Reactive dyes have found applications in dyeing
wool, nylon, cotton, and cellulose fiber. The chromophores of the reactive dyes are
azo, phthalocyanine, and triarylmethane (Chiou and Li 2003). Vat dyes are water
insoluble and commonly consumed in dyeing rayon fibers, wool, and cotton
(Karcher et al. 2001).
R. M. Moattari and T. Mohammadi
solution was as bad as using synthetic dyes. This is because of the fact that a mordant is needed to ensure natural dyes bond to fabrics. A mordant is a type of bonding
agent that helps to bind natural dyes to the material. Mordants are much more dangerous and more toxic than synthetic dyes (Kant 2011). Today, synthetic dyes are
staple materials which are used for colorizing cosmetics, textiles, printing, and plastics (Abdi et al. 2017; Ahmad et al. 2015). This is when the dyes are naturally rebellious materials and they are not easily degradable. Synthetic dyes have complex
molecular structures owing to their auxochromes and chromophores (Chacko and
Subramaniam 2011; Pan et al. 2017). Today, synthetic dyes are available in many
different types. The synthetic dyes can be categorized based on their chemical structure as presented in Table 16.1.
Sometimes, dyes are classified by their application or even by their solubility, as
tabulated in Table 16.2. Mordant, reactive, acidic, basic, and direct dyes are watersoluble dyes, while disperse, azo, and sulfur are examples of insoluble dyes (Rauf
and Ashraf 2012). Among the various dyes, azo dyes have the highest production
rate (~ 70%) and are the most widely used dyes throughout the world (Cotillas
et al. 2018).
Another classification of dyes is presented in Table 16.3. Acidic dyes are commonly utilized for dyeing wool, silk, nylon, and modified acrylic. These dyes are
also consumed in paper, cosmetics, inkjet printing, food, and leather industries.
Xanthan, azine, triphenylmethane, anthraquinone, nitro, nitroso, and azo are the
main classes of acidic dyes (Salleh et al. 2011). Acid red 57, acid blue 2, orange (I,
II), and methyl orange are conventional acid dyes. Basic dyes are utilized in dyeing
modified nylons, modified polyesters, and polyacrylonitrile as well as in pharmaceutical and paper industries. These are water-soluble cationic dyes and also consumed for wool, silk, and tannin mordant cotton (Salleh et al. 2011; Bouatay et al.
2016). Thiazine, cyanine, acridine, hemicyanine, oxazine, diazahemicyanine, malachite green, basic red 46, basic red 9, basic yellow 28, methylene blue, crystal violet, and basic brown are the main classes of basic dyes. Disperse dyes are utilized on
nylon, cellulose acetate, cellulose fiber, and acrylic fibers. These are water-insoluble
and nonionic dyes. The major classes are nitro, benzodifuranone, azo, anthraquinone, and styryl groups. Disperse blue, disperse yellow, disperse red, and disperse
orange are some usual examples (Forgacs et al. 2004).
Direct dyes are commonly utilized in dyeing cotton, leather, rayon, and paper
industries. If the dyeing process takes place in aqueous electrolytic solutions, direct
dyes have affinity to cellulose fiber. Stilbenes, oxazine, and polyazo compounds are
the major classes of direct dyes. Reactive dyes have found applications in dyeing
wool, nylon, cotton, and cellulose fiber. The chromophores of the reactive dyes are
azo, phthalocyanine, and triarylmethane (Chiou and Li 2003). Vat dyes are water
insoluble and commonly consumed in dyeing rayon fibers, wool, and cotton
(Karcher et al. 2001).
R. M. Moattari and T. Mohammadi