Tratamiento electroquímico Tratamiento electroquímico de de colorantes bifuncionales tipo hexl en un colorantes bifuncionales tipo hexl en un reactor fi ltro prensa reactor fi ltro prensa

Abstract

In the present work, the electro chemical 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 125 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 (TOC) and the Chemical Oxygen Demand (COD) were measured. These parameters allowed to know the Average Oxidation 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 decoloration 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.