Dyes: Classification, Pollution, and Environmental Effects

There are a wide variety of textile dyes including reactive, direct, vat, sulfur, disperse, basic, and acid dyes. Therefore, the classification of dyes has become mandatory due to the increase in the annual global production of these compounds. They can be classified according to their chemical compositions (azo, anthraquinone, nitroso, nitro, indigoide, cyanine, phtalocyanine, and triphenylmethane) or according to their field of application to different substrates such as textile fibers, paper, leathers, and plastics. In our new investigation, we have been able to describe the different families of textile dyes according to their chemical structures (chromophoric/auxochromic), application methods in the textile industry, and their Color Index (C.I). The presence of these dyes in the liquid effluents from washing textiles cause a negative impact on the balance of the aquatic environment, which requires prior treatment of these effluents.