Electrocoagulation of textile wastewater bearing disperse dyes

The paper describes a study on the removal of colour from textile wastewater bearing a mixture of three disperse dyes. The experiments were carried out in a reactor equipped with an Al sacrificial anode (100 cm2) and a stainless steel cathode of the same dimensions. Decolorisation occurred as a result of destabilisation of colloids due to an effect of an electric field generated between the electrodes (polarisation coagulation) and the reactions with coagulating compounds, formed in situ during anode oxidation (volumetric coagulation), followed by a subsequent flotation of agglomerates of the particles. During the study the following parameters were varied: initial pH of the solution, current density (between 100 and 300 A m-2) and an initial concentration of the dyes. The best results of elimination of colour, equal to 99%, were obtained during 5 minutes of treatment under the conditions of pH of 9 and the G factor equal to 41.