Azo Dyes: Characterization and Toxicity– A Review

The emission of effluents from textile industries has been a major concern of the modern world, due to the great pollution that these effluents promote on the water resources. Among the synthetic dyes released in effluents from textile industries, azo dyes is one of the more detrimental classes because it is highly persistent in the aquatic environment, due to its chemical compositions, involving aromatic rings, azoic linkages and amino groups. This review aimed to gather information on the importance of the production and industrial use of azo dyes, as well as present some studies that have been developed to evaluate the toxicity of such chemical compounds and their metabolites on different living organisms. This paper presents some considerations on the importance of the biological treatment of textile effluents, the discovery of microorganisms capable of degrading azo dyes efficiently in order to reduce potential risks of these dyes to organisms and environment.