Degradation of Anthroquinone Dyes Stimulated by Fungi - Microbial Degradation of Synthetic Dyes in Wastewaters - page 327

Anthraquinone

Drimarene Blue K 2 RL Remazol Brilliant Blue R (RBBR)

Reactive Blue 4 (RB4) Reactive Blue 19 (RB19)

Fig. 1 Chemical structure of anthraquinone and its derivatives

chromophore of reactive dyes. However, anthraquinone dyes are derived from
anthraquinone having a quinoid ring as the chromophore. It may also contain
hydroxyl groups or amino groups in their general structure acting as a chromophore
(Fig. 1 ). Anthraquinone dyes are not only resistant to microbial degradation but also
toxic, carcinogenic and mutagenic in nature (Itoh et al. 1996 ). During decoloriza-
tion, anthraquinone dyes get converted into a very harmful compound, i.e.,

benzidine.
Since synthetic dyes are generally very recalcitrant in nature, they can tbe

removed by conventional wastewater treatments, such as adsorption, photooxida-
tion, coagulation,

'

occulation, photo and chemical degradation. The chemical
methods produce toxic compounds by the cleavage of chromophoric groups present
in the dye which is a major disadvantage associated with this method (Robinson
et al. 2001 ). However, the biological treatment is often economical and eco-friendly