A comparative study on characterization of textile wastewaters (untreated and treated) toxicity by chemical and biological tests

Decolorization and mineralization of Allura Red AC azo dye by solar photoelectro-Fenton: Identification of intermediates

“…They are used in many industries due to their interesting properties like brilliant shades, relative low cost and simple manufacture (Robinson et al, 2001;Hunger, 2003;Zollinger, 2003;Forgacs et al, 2004). However, there is increasing concern on the environmental impact of dyeing industrial effluents (UNESCO, 2012), since they may contain high levels of dyestuffs (i.e., 100-250 mg L À1 ) and cause aesthetic problems and toxic effects on living beings (Sharma et al, 2007;Ulson de Souza et al, 2007). In particular, according to the European Food Safety Authority (EFSA, 2008(EFSA, , 2009, food azo dyes can be hazardous because they are connected to children hyperactivity and possible allergies and intolerances.…”

Degradation of the azo dye Acid Red 1 by anodic oxidation and indirect electrochemical processes based on Fenton's reaction chemistry. Relationship between decolorization, mineralization and products

“…They have the azo group (−N = N − ) as chromophore, associated with aromatic systems containing groups such as −OH and −SO 3 H. Azo dyes are highly recalcitrant and are hardly removed by conventional biological and physicochemical methods, thus persisting in the aquatic environment [2,3]. They are toxic to aquatic organisms and humans [4,5] and possess carcinogenic, mutagenic and bactericide properties [1]. The development of powerful and effective oxidation processes to remove azo dyes and their by-products from wastewaters are required to avoid their adverse environmental impact and the danger they imply to public health.…”

Degradation of Acid Violet 7 and Reactive Black 5 in Water by Electro-Fenton and Photo Electro-Fenton By

“…Color in water is a consequence of small quantities of dyes, interfering with transmissions of sunlight into natural streams. Azo dyes and their intermediate products, such as aromatic amines, are toxic to aquatic life; carcinogenic and mutagenic to humans 2,3 . For these reasons, dyes must be removed from textile wastewaters before being discharged.…”