In the present work, electrocoagulation was applied for the colour removal of solutions containing Direct red 81. Experiments were performed for synthetic solutions in batch mode. The study focuses on the effect of following operational parameters: electrolysis time, current density, initial pH, inter-electrode distance, initial dye concentration and type of supporting electrolyte. The obtained results showed that decolouration optimal conditions are the following: initial pH of about 6, current density of 1.875 mA/cm(2). inter-electrode distance of 1.5 cm and finally the use of NaCl as supporting electrolyte. In best conditions, high decolouration efficiency was obtained, reaching more than 98% of colour removal. Fourier transform infrared spectroscopy (FTIR) analysis was used to characterize the residual EC by-product with and without the presence of dye. (C) 2010 Elsevier B.V. All rights reserved.