ELECTROCHEMICAL TREATMENT OF BIFUNCTIONAL DYES IN A FILTER PRESS REACTOR

In the present work, the electrochemical treatment of reactive bifunctional dyes is investigated. The selected dyes correspond to the tricromy HEXL. These dyes present two azo groups as chromophore groups and two monochlorotriazinic groups as reactive groups. This study has been carried out in two parts: in the first part synthetic solutions containing just one of these dyes, Procion HEXL, were studied (Solution (1)). Previous investigations have demonstrated that the best process to carry out this study is the oxido-reduction at 1 25 mA cm-2. Following to this first part, the same study in the same working conditions was performed with solutions containing the three dyes of the tricromy H-EXL (Procion Yellow HEXL, Procion Crimson HEXL and Procion Navy HEXL). In this last case, the concentrations were selected considering the concentrations found in real effluents. In order to evaluate the decoloration/mineralization obtained, Total Organic Carbon (TOO and the Chemical Oxygen Demand (COD) were measured. These parameters allowed to know the Average Ox dation State (AOS) after each electrolysis and the efficiency at which the process takes place by means of calculating the Carbon Oxidation State (COS and The Average Current Efficiency (ACE). The UV-Visible spectroscopy permitted to observe the deceleration differences between the initial and final stage. Moreover, the High Performance Liquid Chromatography (HPLC) gave information about the intermediates generated as well as the decoloration kinetics.