Paper: THE ELECTROCHEMICAL OXIDATION AS AN ALTERNATIVE FOR COLOR REMOVAL

Biological treatments do not usually achieve the color removal of the textile wastewater, especially when they contain reactive dyes, which have little absorption in conventional biomasses. The problem with the elimination of reactive dyes becomes even more significant due to their poor fiber fixation.Residual reactive dyes can be removed from textile effluents by electrochemical oxidation, carried out with a small commercial cell in order to avoid the design of a specific cell for each company. In a previous work, a design of experiments, type 27–3, was employed in order to select the optimal work conditions and to establish a general methodology for dyes containing different types of chromophores and reactive groups.In the present work, several textile effluents are studied to obtain the decolorisation efficiency and the cost of this method. This design results are applied to 5 prototypes of colored textile effluents which dyeing electrolyte is NaCl. All the studied reactive dyes behave in a very similar way under the electrochemical process, independently of the chromophore or the reactive group contained in their molecule.In general, a lower cost is obtained when the electrochemical oxidation is carried out only over the most concentrated liquors instead of mixing all of them before the treatment. However, when the liquor ratio is very low, the difference in the cost between both forms of processing is not significant.