Electrocoagulation of indigo carmine dye solution with magnesium and AZ31 alloy anodes

Indigo carmine is one of the most polluting components found in the textile industry effluents. It was carried out an exploratory study about the performance of the high purity magnesium and the alloy AZ31 used as sacrifice electrodes for removing color and dissolved organic carbon (DOC) in indigo carmine solutions treated by the electrocoagulation process. Tests were developed through a two levels fractionate factorial design. Factors and levels were: stirring speed (zero or 840 rpm), temperature (28 or 50 °C), dye concentration (100 or 300 mg/L) and current density (20 or 50 A/m2). It was used a concentration NaCl as support electrolyte, and contrary to other studies all the runs were carried out at the same electric charge (5,000 C/L). Removals around 99% colour and 84% in DOC were obtained. Both materials were competitive for colour and DOC removal.