Electrochemical Decolorization and Removal of Indigo Carmine Textile Dye from Wastewater

Abstract

<p>The present paper discusses an integrated electrochemical decolorization/degradation treatment procedure of indigo carmine dye, which comprises electrocoagulation, electrooxidation and advanced electrochemical oxidation using the electro-Fenton process.</p> <p>The electrocoagulation process is performed by sacrificial iron electrodes, the indirect electrooxidation process by dimensionally stable Ti/Pt and graphite electrodes in NaCl electrolyte solution, and the electro-Fenton process by iron electrodes and added amounts of H<sub>2</sub>O<sub>2</sub>. All electrochemical experiments are conducted in the same electrochemical cell with the same apparent electrode surface and inter-electrode distance.</p> <div> <p>The three different electrochemical processes are discussed, their efficiencies compared and evaluated. The initial dye concentration of 100 mg l<sup>-1</sup> was fast and efficiently removed in only a few minutes of electroprocessing time. The electro-Fenton treatment is the fastest, most efficient and economical process operated at very low current densities of 0.33 and 0.66 mA cm<sup>-2</sup> and consuming only 4.75x10<sup>-3</sup> and 5.23x10<sup>-3</sup> kWh m<sup>-3</sup> of treated solution respectively. The electrocoagulation treatment with iron electrodes and the electrooxidation process with Ti/Pt electrodes conducted at applied current densities of 5 mA cm<sup>-2</sup> consumed 0.511 and 0.825 kWh m<sup>-3</sup> of treated solution respectively. The proposed procedure is a safe, economical and efficient method for removal of indigo carmine dye from aqueous solutions and dye house effluents.</p> </div> <p> </p>