Electrochemical Treatment of C.I. Reactive Black 5 Solutions on Stabilized Doped Ti/SnO2 Electrodes

The electrochemical treatment of wastewaters from the textile industry is a promising technique for substances which are resistant to biodegradation. This paper deals with the electrochemical decolourisation and degradation of synthetic solutions containing a bifunctional reactive dye with a high molecular complexity: C.I. Reactive Black 5. The electrolysis was carried out under galvanostatic conditions employing a filter press reactor with two different configurations. A divided filter press reactor (D-FPR) to study only the oxidation process and an undivided filter press reactor (UD-FPR) to study the oxido-reduction process. All the processes were evaluated using Ti/SnO2–Sb–Pt and stainless steel electrodes as anode and cathode, respectively. The decolourisation and degradation of the dye were tracked by means of total organic carbon (TOC), chemical oxygen demand (COD) measurements, UV-Visible spectroscopy, as well as high performance liquid chromatography (HPLC). The kinetics of decolourisation was of pseudo-first order for both processes. Average Oxidation State (AOS), Carbon Oxidation State (COS) and Average Current Efficiency (ACE) were also determined